API: Overhaul ApiResult, make format=xml not throw, and add json formatversion

ApiResult was a mess: some methods could only be used with an array
reference instead of manipulating the stored data, methods that had both
array-ref and internal-data versions had names that didn't at all
correspond, some methods that worked on an array reference were
annoyingly non-static, and then the whole mess with setIndexedTagName.

ApiFormatXml is also entirely annoying to deal with, as it liked to
throw exceptions if certain metadata wasn't provided that no other
formatter required. Its legacy also means we have this silly convention
of using empty-string rather than boolean true, annoying restrictions on
keys (leading to things that should be hashes being arrays of key-value
object instead), '*' used as a key all over the place, and so on.

So, changes here:
* ApiResult is no longer an ApiBase or a ContextSource.
* Wherever sensible, ApiResult provides a static method working on an
  arrayref and a non-static method working on internal data.
* Metadata is now always added to ApiResult's internal data structure.
  Formatters are responsible for stripping it if necessary. "raw mode"
  is deprecated.
* New metadata to replace the '*' key, solve the array() => '[]' vs '{}'
  question, and so on.
* New class for formatting warnings and errors using i18n messages, and
  support for multiple errors and a more machine-readable format for
  warnings. For the moment, though, the actual output will not be changing
  yet (see T47843 for future plans).
* New formatversion parameter for format=json and format=php, to select
  between BC mode and the modern output.
* In BC mode, booleans will be converted to empty-string presence style;
  modules currently returning booleans will need to use
  ApiResult::META_BC_BOOLS to preserve their current output.

Actual changes to the API modules' output (e.g. actually returning
booleans for the new formatversion) beyond the use of
ApiResult::setContentValue() are left for a future change.

Bug: T76728
Bug: T57371
Bug: T33629
Change-Id: I7b37295e8862b188d1f3b0cd07f66ac34629678f

17 files changed, 2432 insertions, 115 deletions

diff --git a/tests/phpunit/includes/api/ApiContinuationManagerTest.php b/tests/phpunit/includes/api/ApiContinuationManagerTest.php
new file mode 100644
index 000000000000..ea08c0284748
--- /dev/null
+++ b/tests/phpunit/includes/api/ApiContinuationManagerTest.php
@@ -0,0 +1,195 @@
+<?php
+
+/**
+ * @covers ApiContinuationManager
+ * @group API
+ */
+class ApiContinuationManagerTest extends MediaWikiTestCase {
+
+	private static function getManager( $continue, $allModules, $generatedModules ) {
+		$context = new DerivativeContext( RequestContext::getMain() );
+		$context->setRequest( new FauxRequest( array( 'continue' => $continue ) ) );
+		$main = new ApiMain( $context );
+		return new ApiContinuationManager( $main, $allModules, $generatedModules );
+	}
+
+	public function testContinuation() {
+		$allModules = array(
+			new MockApiQueryBase( 'mock1' ),
+			new MockApiQueryBase( 'mock2' ),
+			new MockApiQueryBase( 'mocklist' ),
+		);
+		$generator = new MockApiQueryBase( 'generator' );
+
+		$manager = self::getManager( '', $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( 'ApiMain', $manager->getSource() );
+		$this->assertSame( false, $manager->isGeneratorDone() );
+		$this->assertSame( $allModules, $manager->getRunModules() );
+		$manager->addContinueParam( $allModules[0], 'm1continue', array( 1, 2 ) );
+		$manager->addContinueParam( $allModules[2], 'mlcontinue', 2 );
+		$manager->addGeneratorContinueParam( $generator, 'gcontinue', 3 );
+		$this->assertSame( array( array(
+			'mlcontinue' => 2,
+			'm1continue' => '1|2',
+			'continue' => '||mock2',
+		), false ), $manager->getContinuation() );
+		$this->assertSame( array(
+			'mock1' => array( 'm1continue' => '1|2' ),
+			'mocklist' => array( 'mlcontinue' => 2 ),
+			'generator' => array( 'gcontinue' => 3 ),
+		), $manager->getRawContinuation() );
+
+		$result = new ApiResult( 0 );
+		$manager->setContinuationIntoResult( $result );
+		$this->assertSame( array(
+			'mlcontinue' => 2,
+			'm1continue' => '1|2',
+			'continue' => '||mock2',
+		), $result->getResultData( 'continue' ) );
+		$this->assertSame( null, $result->getResultData( 'batchcomplete' ) );
+
+		$manager = self::getManager( '', $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( false, $manager->isGeneratorDone() );
+		$this->assertSame( $allModules, $manager->getRunModules() );
+		$manager->addContinueParam( $allModules[0], 'm1continue', array( 1, 2 ) );
+		$manager->addGeneratorContinueParam( $generator, 'gcontinue', array( 3, 4 ) );
+		$this->assertSame( array( array(
+			'm1continue' => '1|2',
+			'continue' => '||mock2|mocklist',
+		), false ), $manager->getContinuation() );
+		$this->assertSame( array(
+			'mock1' => array( 'm1continue' => '1|2' ),
+			'generator' => array( 'gcontinue' => '3|4' ),
+		), $manager->getRawContinuation() );
+
+		$manager = self::getManager( '', $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( false, $manager->isGeneratorDone() );
+		$this->assertSame( $allModules, $manager->getRunModules() );
+		$manager->addContinueParam( $allModules[2], 'mlcontinue', 2 );
+		$manager->addGeneratorContinueParam( $generator, 'gcontinue', 3 );
+		$this->assertSame( array( array(
+			'mlcontinue' => 2,
+			'gcontinue' => 3,
+			'continue' => 'gcontinue||',
+		), true ), $manager->getContinuation() );
+		$this->assertSame( array(
+			'mocklist' => array( 'mlcontinue' => 2 ),
+			'generator' => array( 'gcontinue' => 3 ),
+		), $manager->getRawContinuation() );
+
+		$result = new ApiResult( 0 );
+		$manager->setContinuationIntoResult( $result );
+		$this->assertSame( array(
+			'mlcontinue' => 2,
+			'gcontinue' => 3,
+			'continue' => 'gcontinue||',
+		), $result->getResultData( 'continue' ) );
+		$this->assertSame( '', $result->getResultData( 'batchcomplete' ) );
+
+		$manager = self::getManager( '', $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( false, $manager->isGeneratorDone() );
+		$this->assertSame( $allModules, $manager->getRunModules() );
+		$manager->addGeneratorContinueParam( $generator, 'gcontinue', 3 );
+		$this->assertSame( array( array(
+			'gcontinue' => 3,
+			'continue' => 'gcontinue||mocklist',
+		), true ), $manager->getContinuation() );
+		$this->assertSame( array(
+			'generator' => array( 'gcontinue' => 3 ),
+		), $manager->getRawContinuation() );
+
+		$manager = self::getManager( '', $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( false, $manager->isGeneratorDone() );
+		$this->assertSame( $allModules, $manager->getRunModules() );
+		$manager->addContinueParam( $allModules[0], 'm1continue', array( 1, 2 ) );
+		$manager->addContinueParam( $allModules[2], 'mlcontinue', 2 );
+		$this->assertSame( array( array(
+			'mlcontinue' => 2,
+			'm1continue' => '1|2',
+			'continue' => '||mock2',
+		), false ), $manager->getContinuation() );
+		$this->assertSame( array(
+			'mock1' => array( 'm1continue' => '1|2' ),
+			'mocklist' => array( 'mlcontinue' => 2 ),
+		), $manager->getRawContinuation() );
+
+		$manager = self::getManager( '', $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( false, $manager->isGeneratorDone() );
+		$this->assertSame( $allModules, $manager->getRunModules() );
+		$manager->addContinueParam( $allModules[0], 'm1continue', array( 1, 2 ) );
+		$this->assertSame( array( array(
+			'm1continue' => '1|2',
+			'continue' => '||mock2|mocklist',
+		), false ), $manager->getContinuation() );
+		$this->assertSame( array(
+			'mock1' => array( 'm1continue' => '1|2' ),
+		), $manager->getRawContinuation() );
+
+		$manager = self::getManager( '', $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( false, $manager->isGeneratorDone() );
+		$this->assertSame( $allModules, $manager->getRunModules() );
+		$manager->addContinueParam( $allModules[2], 'mlcontinue', 2 );
+		$this->assertSame( array( array(
+			'mlcontinue' => 2,
+			'continue' => '-||mock1|mock2',
+		), true ), $manager->getContinuation() );
+		$this->assertSame( array(
+			'mocklist' => array( 'mlcontinue' => 2 ),
+		), $manager->getRawContinuation() );
+
+		$manager = self::getManager( '', $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( false, $manager->isGeneratorDone() );
+		$this->assertSame( $allModules, $manager->getRunModules() );
+		$this->assertSame( array( array(), true ), $manager->getContinuation() );
+		$this->assertSame( array(), $manager->getRawContinuation() );
+
+		$manager = self::getManager( '||mock2', $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( false, $manager->isGeneratorDone() );
+		$this->assertSame(
+			array_values( array_diff_key( $allModules, array( 1 => 1 ) ) ),
+			$manager->getRunModules()
+		);
+
+		$manager = self::getManager( '-||', $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( true, $manager->isGeneratorDone() );
+		$this->assertSame(
+			array_values( array_diff_key( $allModules, array( 0 => 0, 1 => 1 ) ) ),
+			$manager->getRunModules()
+		);
+
+		try {
+			self::getManager( 'foo', $allModules, array( 'mock1', 'mock2' ) );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( UsageException $ex ) {
+			$this->assertSame(
+				'Invalid continue param. You should pass the original value returned by the previous query',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+
+		$manager = self::getManager( '||mock2', array_slice( $allModules, 0, 2 ), array( 'mock1', 'mock2' ) );
+		try {
+			$manager->addContinueParam( $allModules[1], 'm2continue', 1 );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( UnexpectedValueException $ex ) {
+			$this->assertSame(
+				'Module \'mock2\' was not supposed to have been executed, but it was executed anyway',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+		try {
+			$manager->addContinueParam( $allModules[2], 'mlcontinue', 1 );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( UnexpectedValueException $ex ) {
+			$this->assertSame(
+				'Module \'mocklist\' called ApiContinuationManager::addContinueParam but was not passed to ApiContinuationManager::__construct',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+
+	}
+
+}
diff --git a/tests/phpunit/includes/api/ApiErrorFormatterTest.php b/tests/phpunit/includes/api/ApiErrorFormatterTest.php
new file mode 100644
index 000000000000..344af62fddeb
--- /dev/null
+++ b/tests/phpunit/includes/api/ApiErrorFormatterTest.php
@@ -0,0 +1,343 @@
+<?php
+
+/**
+ * @group API
+ */
+class ApiErrorFormatterTest extends MediaWikiTestCase {
+
+	/**
+	 * @covers ApiErrorFormatter
+	 * @dataProvider provideErrorFormatter
+	 */
+	public function testErrorFormatter( $format, $lang, $useDB,
+		$expect1, $expect2, $expect3
+	) {
+		$result = new ApiResult( 8388608 );
+		$formatter = new ApiErrorFormatter( $result, Language::factory( $lang ), $format, $useDB );
+
+		$formatter->addWarning( 'string', 'mainpage' );
+		$formatter->addError( 'err', 'mainpage' );
+		$this->assertSame( $expect1, $result->getResultData(), 'Simple test' );
+
+		$result->reset();
+		$formatter->addWarning( 'foo', 'mainpage' );
+		$formatter->addWarning( 'foo', 'mainpage' );
+		$formatter->addWarning( 'foo', array( 'parentheses', 'foobar' ) );
+		$msg1 = wfMessage( 'mainpage' );
+		$formatter->addWarning( 'message', $msg1 );
+		$msg2 = new ApiMessage( 'mainpage', 'overriddenCode', array( 'overriddenData' => true ) );
+		$formatter->addWarning( 'messageWithData', $msg2 );
+		$formatter->addError( 'errWithData', $msg2 );
+		$this->assertSame( $expect2, $result->getResultData(), 'Complex test' );
+
+		$result->reset();
+		$status = Status::newGood();
+		$status->warning( 'mainpage' );
+		$status->warning( 'parentheses', 'foobar' );
+		$status->warning( $msg1 );
+		$status->warning( $msg2 );
+		$status->error( 'mainpage' );
+		$status->error( 'parentheses', 'foobar' );
+		$formatter->addMessagesFromStatus( 'status', $status );
+		$this->assertSame( $expect3, $result->getResultData(), 'Status test' );
+
+		$this->assertSame(
+			$expect3['errors']['status'],
+			$formatter->arrayFromStatus( $status, 'error' ),
+			'arrayFromStatus test for error'
+		);
+		$this->assertSame(
+			$expect3['warnings']['status'],
+			$formatter->arrayFromStatus( $status, 'warning' ),
+			'arrayFromStatus test for warning'
+		);
+	}
+
+	public static function provideErrorFormatter() {
+		$mainpagePlain = wfMessage( 'mainpage' )->useDatabase( false )->plain();
+		$parensPlain = wfMessage( 'parentheses', 'foobar' )->useDatabase( false )->plain();
+		$mainpageText = wfMessage( 'mainpage' )->inLanguage( 'de' )->text();
+		$parensText = wfMessage( 'parentheses', 'foobar' )->inLanguage( 'de' )->text();
+		$C = ApiResult::META_CONTENT;
+		$I = ApiResult::META_INDEXED_TAG_NAME;
+
+		return array(
+			array( 'wikitext', 'de', true,
+				array(
+					'errors' => array(
+						'err' => array(
+							array( 'code' => 'mainpage', 'text' => $mainpageText, $C => 'text' ),
+							$I => 'error',
+						),
+					),
+					'warnings' => array(
+						'string' => array(
+							array( 'code' => 'mainpage', 'text' => $mainpageText, $C => 'text' ),
+							$I => 'warning',
+						),
+					),
+				),
+				array(
+					'errors' => array(
+						'errWithData' => array(
+							array( 'code' => 'overriddenCode', 'text' => $mainpageText,
+								'overriddenData' => true, $C => 'text' ),
+							$I => 'error',
+						),
+					),
+					'warnings' => array(
+						'messageWithData' => array(
+							array( 'code' => 'overriddenCode', 'text' => $mainpageText,
+								'overriddenData' => true, $C => 'text' ),
+							$I => 'warning',
+						),
+						'message' => array(
+							array( 'code' => 'mainpage', 'text' => $mainpageText, $C => 'text' ),
+							$I => 'warning',
+						),
+						'foo' => array(
+							array( 'code' => 'mainpage', 'text' => $mainpageText, $C => 'text' ),
+							array( 'code' => 'parentheses', 'text' => $parensText, $C => 'text' ),
+							$I => 'warning',
+						),
+					),
+				),
+				array(
+					'errors' => array(
+						'status' => array(
+							array( 'code' => 'mainpage', 'text' => $mainpageText, $C => 'text' ),
+							array( 'code' => 'parentheses', 'text' => $parensText, $C => 'text' ),
+							$I => 'error',
+						),
+					),
+					'warnings' => array(
+						'status' => array(
+							array( 'code' => 'mainpage', 'text' => $mainpageText, $C => 'text' ),
+							array( 'code' => 'parentheses', 'text' => $parensText, $C => 'text' ),
+							array( 'code' => 'overriddenCode', 'text' => $mainpageText,
+								'overriddenData' => true, $C => 'text' ),
+							$I => 'warning',
+						),
+					),
+				),
+			),
+			array( 'raw', 'fr', true,
+				array(
+					'errors' => array(
+						'err' => array(
+							array( 'code' => 'mainpage', 'message' => 'mainpage', 'params' => array( $I => 'param' ) ),
+							$I => 'error',
+						),
+					),
+					'warnings' => array(
+						'string' => array(
+							array( 'code' => 'mainpage', 'message' => 'mainpage', 'params' => array( $I => 'param' ) ),
+							$I => 'warning',
+						),
+					),
+				),
+				array(
+					'errors' => array(
+						'errWithData' => array(
+							array( 'code' => 'overriddenCode', 'message' => 'mainpage', 'params' => array( $I => 'param' ),
+								'overriddenData' => true ),
+							$I => 'error',
+						),
+					),
+					'warnings' => array(
+						'messageWithData' => array(
+							array( 'code' => 'overriddenCode', 'message' => 'mainpage', 'params' => array( $I => 'param' ),
+								'overriddenData' => true ),
+							$I => 'warning',
+						),
+						'message' => array(
+							array( 'code' => 'mainpage', 'message' => 'mainpage', 'params' => array( $I => 'param' ) ),
+							$I => 'warning',
+						),
+						'foo' => array(
+							array( 'code' => 'mainpage', 'message' => 'mainpage', 'params' => array( $I => 'param' ) ),
+							array( 'code' => 'parentheses', 'message' => 'parentheses', 'params' => array( 'foobar', $I => 'param' ) ),
+							$I => 'warning',
+						),
+					),
+				),
+				array(
+					'errors' => array(
+						'status' => array(
+							array( 'code' => 'mainpage', 'message' => 'mainpage', 'params' => array( $I => 'param' ) ),
+							array( 'code' => 'parentheses', 'message' => 'parentheses', 'params' => array( 'foobar', $I => 'param' ) ),
+							$I => 'error',
+						),
+					),
+					'warnings' => array(
+						'status' => array(
+							array( 'code' => 'mainpage', 'message' => 'mainpage', 'params' => array( $I => 'param' ) ),
+							array( 'code' => 'parentheses', 'message' => 'parentheses', 'params' => array( 'foobar', $I => 'param' ) ),
+							array( 'code' => 'overriddenCode', 'message' => 'mainpage', 'params' => array( $I => 'param' ),
+								'overriddenData' => true ),
+							$I => 'warning',
+						),
+					),
+				),
+			),
+			array( 'none', 'fr', true,
+				array(
+					'errors' => array(
+						'err' => array(
+							array( 'code' => 'mainpage' ),
+							$I => 'error',
+						),
+					),
+					'warnings' => array(
+						'string' => array(
+							array( 'code' => 'mainpage' ),
+							$I => 'warning',
+						),
+					),
+				),
+				array(
+					'errors' => array(
+						'errWithData' => array(
+							array( 'code' => 'overriddenCode', 'overriddenData' => true ),
+							$I => 'error',
+						),
+					),
+					'warnings' => array(
+						'messageWithData' => array(
+							array( 'code' => 'overriddenCode', 'overriddenData' => true ),
+							$I => 'warning',
+						),
+						'message' => array(
+							array( 'code' => 'mainpage' ),
+							$I => 'warning',
+						),
+						'foo' => array(
+							array( 'code' => 'mainpage' ),
+							array( 'code' => 'parentheses' ),
+							$I => 'warning',
+						),
+					),
+				),
+				array(
+					'errors' => array(
+						'status' => array(
+							array( 'code' => 'mainpage' ),
+							array( 'code' => 'parentheses' ),
+							$I => 'error',
+						),
+					),
+					'warnings' => array(
+						'status' => array(
+							array( 'code' => 'mainpage' ),
+							array( 'code' => 'parentheses' ),
+							array( 'code' => 'overriddenCode', 'overriddenData' => true ),
+							$I => 'warning',
+						),
+					),
+				),
+			),
+		);
+	}
+
+	/**
+	 * @covers ApiErrorFormatter_BackCompat
+	 */
+	public function testErrorFormatterBC() {
+		$mainpagePlain = wfMessage( 'mainpage' )->useDatabase( false )->plain();
+		$parensPlain = wfMessage( 'parentheses', 'foobar' )->useDatabase( false )->plain();
+
+		$result = new ApiResult( 8388608 );
+		$formatter = new ApiErrorFormatter_BackCompat( $result );
+
+		$formatter->addWarning( 'string', 'mainpage' );
+		$formatter->addError( 'err', 'mainpage' );
+		$this->assertSame( array(
+			'error' => array(
+				'code' => 'mainpage',
+				'info' => $mainpagePlain,
+			),
+			'warnings' => array(
+				'string' => array(
+					'warnings' => $mainpagePlain,
+					ApiResult::META_CONTENT => 'warnings',
+				),
+			),
+		), $result->getResultData(), 'Simple test' );
+
+		$result->reset();
+		$formatter->addWarning( 'foo', 'mainpage' );
+		$formatter->addWarning( 'foo', 'mainpage' );
+		$formatter->addWarning( 'foo', array( 'parentheses', 'foobar' ) );
+		$msg1 = wfMessage( 'mainpage' );
+		$formatter->addWarning( 'message', $msg1 );
+		$msg2 = new ApiMessage( 'mainpage', 'overriddenCode', array( 'overriddenData' => true ) );
+		$formatter->addWarning( 'messageWithData', $msg2 );
+		$formatter->addError( 'errWithData', $msg2 );
+		$this->assertSame( array(
+			'error' => array(
+				'code' => 'overriddenCode',
+				'info' => $mainpagePlain,
+				'overriddenData' => true,
+			),
+			'warnings' => array(
+				'messageWithData' => array(
+					'warnings' => $mainpagePlain,
+					ApiResult::META_CONTENT => 'warnings',
+				),
+				'message' => array(
+					'warnings' => $mainpagePlain,
+					ApiResult::META_CONTENT => 'warnings',
+				),
+				'foo' => array(
+					'warnings' => "$mainpagePlain\n$parensPlain",
+					ApiResult::META_CONTENT => 'warnings',
+				),
+			),
+		), $result->getResultData(), 'Complex test' );
+
+		$result->reset();
+		$status = Status::newGood();
+		$status->warning( 'mainpage' );
+		$status->warning( 'parentheses', 'foobar' );
+		$status->warning( $msg1 );
+		$status->warning( $msg2 );
+		$status->error( 'mainpage' );
+		$status->error( 'parentheses', 'foobar' );
+		$formatter->addMessagesFromStatus( 'status', $status );
+		$this->assertSame( array(
+			'error' => array(
+				'code' => 'parentheses',
+				'info' => $parensPlain,
+			),
+			'warnings' => array(
+				'status' => array(
+					'warnings' => "$mainpagePlain\n$parensPlain",
+					ApiResult::META_CONTENT => 'warnings',
+				),
+			),
+		), $result->getResultData(), 'Status test' );
+
+		$I = ApiResult::META_INDEXED_TAG_NAME;
+		$this->assertSame(
+			array(
+				array( 'type' => 'error', 'message' => 'mainpage', 'params' => array( $I => 'param' ) ),
+				array( 'type' => 'error', 'message' => 'parentheses', 'params' => array( 'foobar', $I => 'param' ) ),
+				$I => 'error',
+			),
+			$formatter->arrayFromStatus( $status, 'error' ),
+			'arrayFromStatus test for error'
+		);
+		$this->assertSame(
+			array(
+				array( 'type' => 'warning', 'message' => 'mainpage', 'params' => array( $I => 'param' ) ),
+				array( 'type' => 'warning', 'message' => 'parentheses', 'params' => array( 'foobar', $I => 'param' ) ),
+				array( 'message' => 'mainpage', 'params' => array( $I => 'param' ), 'type' => 'warning' ),
+				array( 'message' => 'mainpage', 'params' => array( $I => 'param' ), 'type' => 'warning' ),
+				$I => 'warning',
+			),
+			$formatter->arrayFromStatus( $status, 'warning' ),
+			'arrayFromStatus test for warning'
+		);
+	}
+
+}
diff --git a/tests/phpunit/includes/api/ApiMainTest.php b/tests/phpunit/includes/api/ApiMainTest.php
index 7a03f7d27c8a..e8ef18049c85 100644
--- a/tests/phpunit/includes/api/ApiMainTest.php
+++ b/tests/phpunit/includes/api/ApiMainTest.php
@@ -16,7 +16,7 @@ class ApiMainTest extends ApiTestCase {
 			new FauxRequest( array( 'action' => 'query', 'meta' => 'siteinfo' ) )
 		);
 		$api->execute();
-		$data = $api->getResultData();
+		$data = $api->getResult()->getResultData();
 		$this->assertInternalType( 'array', $data );
 		$this->assertArrayHasKey( 'query', $data );
 	}
diff --git a/tests/phpunit/includes/api/ApiMessageTest.php b/tests/phpunit/includes/api/ApiMessageTest.php
new file mode 100644
index 000000000000..6c3ce60d18df
--- /dev/null
+++ b/tests/phpunit/includes/api/ApiMessageTest.php
@@ -0,0 +1,103 @@
+<?php
+
+/**
+ * @group API
+ */
+class ApiMessageTest extends MediaWikiTestCase {
+
+	private function compareMessages( $msg, $msg2 ) {
+		$this->assertSame( $msg->getKey(), $msg2->getKey(), 'getKey' );
+		$this->assertSame( $msg->getKeysToTry(), $msg2->getKeysToTry(), 'getKeysToTry' );
+		$this->assertSame( $msg->getParams(), $msg2->getParams(), 'getParams' );
+		$this->assertSame( $msg->getFormat(), $msg2->getFormat(), 'getFormat' );
+		$this->assertSame( $msg->getLanguage(), $msg2->getLanguage(), 'getLanguage' );
+
+		$msg = TestingAccessWrapper::newFromObject( $msg );
+		$msg2 = TestingAccessWrapper::newFromObject( $msg2 );
+		foreach ( array( 'interface', 'useDatabase', 'title' ) as $key ) {
+			$this->assertSame( $msg->$key, $msg2->$key, $key );
+		}
+	}
+
+	/**
+	 * @covers ApiMessage
+	 */
+	public function testApiMessage() {
+		$msg = new Message( array( 'foo', 'bar' ), array( 'baz' ) );
+		$msg->inLanguage( 'de' )->title( Title::newMainPage() );
+		$msg2 = new ApiMessage( $msg, 'code', array( 'data' ) );
+		$this->compareMessages( $msg, $msg2 );
+		$this->assertEquals( 'code', $msg2->getApiCode() );
+		$this->assertEquals( array( 'data' ), $msg2->getApiData() );
+
+		$msg = new Message( array( 'foo', 'bar' ), array( 'baz' ) );
+		$msg2 = new ApiMessage( array( array( 'foo', 'bar' ), 'baz' ), 'code', array( 'data' ) );
+		$this->compareMessages( $msg, $msg2 );
+		$this->assertEquals( 'code', $msg2->getApiCode() );
+		$this->assertEquals( array( 'data' ), $msg2->getApiData() );
+
+		$msg = new Message( 'foo' );
+		$msg2 = new ApiMessage( 'foo' );
+		$this->compareMessages( $msg, $msg2 );
+		$this->assertEquals( 'foo', $msg2->getApiCode() );
+		$this->assertEquals( array(), $msg2->getApiData() );
+
+		$msg2->setApiCode( 'code', array( 'data' ) );
+		$this->assertEquals( 'code', $msg2->getApiCode() );
+		$this->assertEquals( array( 'data' ), $msg2->getApiData() );
+		$msg2->setApiCode( null );
+		$this->assertEquals( 'foo', $msg2->getApiCode() );
+		$this->assertEquals( array( 'data' ), $msg2->getApiData() );
+		$msg2->setApiData( array( 'data2' ) );
+		$this->assertEquals( array( 'data2' ), $msg2->getApiData() );
+	}
+
+	/**
+	 * @covers ApiRawMessage
+	 */
+	public function testApiRawMessage() {
+		$msg = new RawMessage( 'foo', array( 'baz' ) );
+		$msg->inLanguage( 'de' )->title( Title::newMainPage() );
+		$msg2 = new ApiRawMessage( $msg, 'code', array( 'data' ) );
+		$this->compareMessages( $msg, $msg2 );
+		$this->assertEquals( 'code', $msg2->getApiCode() );
+		$this->assertEquals( array( 'data' ), $msg2->getApiData() );
+
+		$msg = new RawMessage( 'foo', array( 'baz' ) );
+		$msg2 = new ApiRawMessage( array( 'foo', 'baz' ), 'code', array( 'data' ) );
+		$this->compareMessages( $msg, $msg2 );
+		$this->assertEquals( 'code', $msg2->getApiCode() );
+		$this->assertEquals( array( 'data' ), $msg2->getApiData() );
+
+		$msg = new RawMessage( 'foo' );
+		$msg2 = new ApiRawMessage( 'foo', 'code', array( 'data' ) );
+		$this->compareMessages( $msg, $msg2 );
+		$this->assertEquals( 'code', $msg2->getApiCode() );
+		$this->assertEquals( array( 'data' ), $msg2->getApiData() );
+
+		$msg2->setApiCode( 'code', array( 'data' ) );
+		$this->assertEquals( 'code', $msg2->getApiCode() );
+		$this->assertEquals( array( 'data' ), $msg2->getApiData() );
+		$msg2->setApiCode( null );
+		$this->assertEquals( 'foo', $msg2->getApiCode() );
+		$this->assertEquals( array( 'data' ), $msg2->getApiData() );
+		$msg2->setApiData( array( 'data2' ) );
+		$this->assertEquals( array( 'data2' ), $msg2->getApiData() );
+	}
+
+	/**
+	 * @covers ApiMessage::create
+	 */
+	public function testApiMessageCreate() {
+		$this->assertInstanceOf( 'ApiMessage', ApiMessage::create( new Message( 'mainpage' ) ) );
+		$this->assertInstanceOf( 'ApiRawMessage', ApiMessage::create( new RawMessage( 'mainpage' ) ) );
+		$this->assertInstanceOf( 'ApiMessage', ApiMessage::create( 'mainpage' ) );
+
+		$msg = new ApiMessage( 'mainpage' );
+		$this->assertSame( $msg, ApiMessage::create( $msg ) );
+
+		$msg = new ApiRawMessage( 'mainpage' );
+		$this->assertSame( $msg, ApiMessage::create( $msg ) );
+	}
+
+}
diff --git a/tests/phpunit/includes/api/ApiOptionsTest.php b/tests/phpunit/includes/api/ApiOptionsTest.php
index bd34018e3f58..51154ae39821 100644
--- a/tests/phpunit/includes/api/ApiOptionsTest.php
+++ b/tests/phpunit/includes/api/ApiOptionsTest.php
@@ -138,7 +138,7 @@ class ApiOptionsTest extends MediaWikiLangTestCase {
 		$this->mContext->setRequest( new FauxRequest( $request, true, $this->mSession ) );
 		$this->mTested->execute();
 
-		return $this->mTested->getResult()->getData();
+		return $this->mTested->getResult()->getResultData( null, array( 'Strip' => 'all' ) );
 	}
 
 	/**
@@ -396,7 +396,7 @@ class ApiOptionsTest extends MediaWikiLangTestCase {
 			'options' => 'success',
 			'warnings' => array(
 				'options' => array(
-					'*' => "Validation error for 'special': cannot be set by this module"
+					'warnings' => "Validation error for 'special': cannot be set by this module"
 				)
 			)
 		), $response );
@@ -419,7 +419,7 @@ class ApiOptionsTest extends MediaWikiLangTestCase {
 			'options' => 'success',
 			'warnings' => array(
 				'options' => array(
-					'*' => "Validation error for 'unknownOption': not a valid preference"
+					'warnings' => "Validation error for 'unknownOption': not a valid preference"
 				)
 			)
 		), $response );
diff --git a/tests/phpunit/includes/api/ApiResultTest.php b/tests/phpunit/includes/api/ApiResultTest.php
new file mode 100644
index 000000000000..7e43a240a718
--- /dev/null
+++ b/tests/phpunit/includes/api/ApiResultTest.php
@@ -0,0 +1,1446 @@
+<?php
+
+/**
+ * @covers ApiResult
+ * @group API
+ */
+class ApiResultTest extends MediaWikiTestCase {
+
+	/**
+	 * @covers ApiResult
+	 */
+	public function testStaticDataMethods() {
+		$arr = array();
+
+		ApiResult::setValue( $arr, 'setValue', '1' );
+
+		ApiResult::setValue( $arr, null, 'unnamed 1' );
+		ApiResult::setValue( $arr, null, 'unnamed 2' );
+
+		ApiResult::setValue( $arr, 'deleteValue', '2' );
+		ApiResult::unsetValue( $arr, 'deleteValue' );
+
+		ApiResult::setContentValue( $arr, 'setContentValue', '3' );
+
+		$this->assertSame( array(
+			'setValue' => '1',
+			'unnamed 1',
+			'unnamed 2',
+			ApiResult::META_CONTENT => 'setContentValue',
+			'setContentValue' => '3',
+		), $arr );
+
+		try {
+			ApiResult::setValue( $arr, 'setValue', '99' );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( RuntimeException $ex ) {
+			$this->assertSame(
+				'Attempting to add element setValue=99, existing value is 1',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+
+		try {
+			ApiResult::setContentValue( $arr, 'setContentValue2', '99' );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( RuntimeException $ex ) {
+			$this->assertSame(
+				'Attempting to set content element as setContentValue2 when setContentValue ' .
+					'is already set as the content element',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+
+		ApiResult::setValue( $arr, 'setValue', '99', ApiResult::OVERRIDE );
+		$this->assertSame( '99', $arr['setValue'] );
+
+		ApiResult::setContentValue( $arr, 'setContentValue2', '99', ApiResult::OVERRIDE );
+		$this->assertSame( 'setContentValue2', $arr[ApiResult::META_CONTENT] );
+
+		$arr = array( 'foo' => 1, 'bar' => 1 );
+		ApiResult::setValue( $arr, 'top', '2', ApiResult::ADD_ON_TOP );
+		ApiResult::setValue( $arr, null, '2', ApiResult::ADD_ON_TOP );
+		ApiResult::setValue( $arr, 'bottom', '2' );
+		ApiResult::setValue( $arr, 'foo', '2', ApiResult::OVERRIDE );
+		ApiResult::setValue( $arr, 'bar', '2', ApiResult::OVERRIDE | ApiResult::ADD_ON_TOP );
+		$this->assertSame( array( 0, 'top', 'foo', 'bar', 'bottom' ), array_keys( $arr ) );
+
+		$arr = array();
+		ApiResult::setValue( $arr, 'sub', array( 'foo' => 1 ) );
+		ApiResult::setValue( $arr, 'sub', array( 'bar' => 1 ) );
+		$this->assertSame( array( 'sub' => array( 'foo' => 1, 'bar' => 1 ) ), $arr );
+
+		try {
+			ApiResult::setValue( $arr, 'sub', array( 'foo' => 2, 'baz' => 2 ) );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( RuntimeException $ex ) {
+			$this->assertSame(
+				'Conflicting keys (foo) when attempting to merge element sub',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+
+		$arr = array();
+		$title = Title::newFromText( "MediaWiki:Foobar" );
+		$obj = new stdClass;
+		$obj->foo = 1;
+		$obj->bar = 2;
+		ApiResult::setValue( $arr, 'title', $title );
+		ApiResult::setValue( $arr, 'obj', $obj );
+		$this->assertSame( array(
+			'title' => (string)$title,
+			'obj' => array( 'foo' => 1, 'bar' => 2, ApiResult::META_TYPE => 'assoc' ),
+		), $arr );
+
+		$fh = tmpfile();
+		try {
+			ApiResult::setValue( $arr, 'file', $fh );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( InvalidArgumentException $ex ) {
+			$this->assertSame(
+				'Cannot add resource(stream) to ApiResult',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+		try {
+			$obj->file = $fh;
+			ApiResult::setValue( $arr, 'sub', $obj );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( InvalidArgumentException $ex ) {
+			$this->assertSame(
+				'Cannot add resource(stream) to ApiResult',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+		fclose( $fh );
+
+		try {
+			ApiResult::setValue( $arr, 'inf', INF );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( InvalidArgumentException $ex ) {
+			$this->assertSame(
+				'Cannot add non-finite floats to ApiResult',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+		try {
+			ApiResult::setValue( $arr, 'nan', NAN );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( InvalidArgumentException $ex ) {
+			$this->assertSame(
+				'Cannot add non-finite floats to ApiResult',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+
+		$arr = array();
+		$result2 = new ApiResult( 8388608 );
+		$result2->addValue( null, 'foo', 'bar' );
+		ApiResult::setValue( $arr, 'baz', $result2 );
+		$this->assertSame( array( 'baz' => array( 'foo' => 'bar' ) ), $arr );
+
+		$arr = array();
+		ApiResult::setValue( $arr, 'foo', "foo\x80bar" );
+		ApiResult::setValue( $arr, 'bar', "a\xcc\x81" );
+		ApiResult::setValue( $arr, 'baz', 74 );
+		$this->assertSame( array(
+			'foo' => "foo\xef\xbf\xbdbar",
+			'bar' => "\xc3\xa1",
+			'baz' => 74,
+		), $arr );
+	}
+
+	/**
+	 * @covers ApiResult
+	 */
+	public function testInstanceDataMethods() {
+		$result = new ApiResult( 8388608 );
+
+		$result->addValue( null, 'setValue', '1' );
+
+		$result->addValue( null, null, 'unnamed 1' );
+		$result->addValue( null, null, 'unnamed 2' );
+
+		$result->addValue( null, 'deleteValue', '2' );
+		$result->removeValue( null, 'deleteValue' );
+
+		$result->addValue( array( 'a', 'b' ), 'deleteValue', '3' );
+		$result->removeValue( array( 'a', 'b', 'deleteValue' ), null, '3' );
+
+		$result->addContentValue( null, 'setContentValue', '3' );
+
+		$this->assertSame( array(
+			'setValue' => '1',
+			'unnamed 1',
+			'unnamed 2',
+			'a' => array( 'b' => array() ),
+			'setContentValue' => '3',
+			ApiResult::META_CONTENT => 'setContentValue',
+		), $result->getResultData() );
+		$this->assertSame( 20, $result->getSize() );
+
+		try {
+			$result->addValue( null, 'setValue', '99' );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( RuntimeException $ex ) {
+			$this->assertSame(
+				'Attempting to add element setValue=99, existing value is 1',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+
+		try {
+			$result->addContentValue( null, 'setContentValue2', '99' );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( RuntimeException $ex ) {
+			$this->assertSame(
+				'Attempting to set content element as setContentValue2 when setContentValue ' .
+					'is already set as the content element',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+
+		$result->addValue( null, 'setValue', '99', ApiResult::OVERRIDE );
+		$this->assertSame( '99', $result->getResultData( array( 'setValue' ) ) );
+
+		$result->addContentValue( null, 'setContentValue2', '99', ApiResult::OVERRIDE );
+		$this->assertSame( 'setContentValue2',
+			$result->getResultData( array( ApiResult::META_CONTENT ) ) );
+
+		$result->reset();
+		$this->assertSame( array(), $result->getResultData() );
+		$this->assertSame( 0, $result->getSize() );
+
+		$result->addValue( null, 'foo', 1 );
+		$result->addValue( null, 'bar', 1 );
+		$result->addValue( null, 'top', '2', ApiResult::ADD_ON_TOP );
+		$result->addValue( null, null, '2', ApiResult::ADD_ON_TOP );
+		$result->addValue( null, 'bottom', '2' );
+		$result->addValue( null, 'foo', '2', ApiResult::OVERRIDE );
+		$result->addValue( null, 'bar', '2', ApiResult::OVERRIDE | ApiResult::ADD_ON_TOP );
+		$this->assertSame( array( 0, 'top', 'foo', 'bar', 'bottom' ),
+			array_keys( $result->getResultData() ) );
+
+		$result->reset();
+		$result->addValue( null, 'foo', array( 'bar' => 1 ) );
+		$result->addValue( array( 'foo', 'top' ), 'x', 2, ApiResult::ADD_ON_TOP );
+		$result->addValue( array( 'foo', 'bottom' ), 'x', 2 );
+		$this->assertSame( array( 'top', 'bar', 'bottom' ),
+			array_keys( $result->getResultData( array( 'foo' ) ) ) );
+
+		$result->reset();
+		$result->addValue( null, 'sub', array( 'foo' => 1 ) );
+		$result->addValue( null, 'sub', array( 'bar' => 1 ) );
+		$this->assertSame( array( 'sub' => array( 'foo' => 1, 'bar' => 1 ) ),
+			$result->getResultData() );
+
+		try {
+			$result->addValue( null, 'sub', array( 'foo' => 2, 'baz' => 2 ) );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( RuntimeException $ex ) {
+			$this->assertSame(
+				'Conflicting keys (foo) when attempting to merge element sub',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+
+		$result->reset();
+		$title = Title::newFromText( "MediaWiki:Foobar" );
+		$obj = new stdClass;
+		$obj->foo = 1;
+		$obj->bar = 2;
+		$result->addValue( null, 'title', $title );
+		$result->addValue( null, 'obj', $obj );
+		$this->assertSame( array(
+			'title' => (string)$title,
+			'obj' => array( 'foo' => 1, 'bar' => 2, ApiResult::META_TYPE => 'assoc' ),
+		), $result->getResultData() );
+
+		$fh = tmpfile();
+		try {
+			$result->addValue( null, 'file', $fh );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( InvalidArgumentException $ex ) {
+			$this->assertSame(
+				'Cannot add resource(stream) to ApiResult',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+		try {
+			$obj->file = $fh;
+			$result->addValue( null, 'sub', $obj );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( InvalidArgumentException $ex ) {
+			$this->assertSame(
+				'Cannot add resource(stream) to ApiResult',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+		fclose( $fh );
+
+		try {
+			$result->addValue( null, 'inf', INF );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( InvalidArgumentException $ex ) {
+			$this->assertSame(
+				'Cannot add non-finite floats to ApiResult',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+		try {
+			$result->addValue( null, 'nan', NAN );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( InvalidArgumentException $ex ) {
+			$this->assertSame(
+				'Cannot add non-finite floats to ApiResult',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+
+		$result->reset();
+		$result->addParsedLimit( 'foo', 12 );
+		$this->assertSame( array( 'limits' => array( 'foo' => 12 ) ), $result->getResultData() );
+		$result->addParsedLimit( 'foo', 13 );
+		$this->assertSame( array( 'limits' => array( 'foo' => 13 ) ), $result->getResultData() );
+		$this->assertSame( null, $result->getResultData( array( 'foo', 'bar', 'baz' ) ) );
+		$this->assertSame( 13, $result->getResultData( array( 'limits', 'foo' ) ) );
+		try {
+			$result->getResultData( array( 'limits', 'foo', 'bar' ) );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( InvalidArgumentException $ex ) {
+			$this->assertSame(
+				'Path limits.foo is not an array',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+
+		$result = new ApiResult( 10 );
+		$formatter = new ApiErrorFormatter( $result, Language::factory( 'en' ), 'none', false );
+		$result->setErrorFormatter( $formatter );
+		$this->assertFalse( $result->addValue( null, 'foo', '12345678901' ) );
+		$this->assertTrue( $result->addValue( null, 'foo', '12345678901', ApiResult::NO_SIZE_CHECK ) );
+		$this->assertSame( 0, $result->getSize() );
+		$result->reset();
+		$this->assertTrue( $result->addValue( null, 'foo', '1234567890' ) );
+		$this->assertFalse( $result->addValue( null, 'foo', '1' ) );
+		$result->removeValue( null, 'foo' );
+		$this->assertTrue( $result->addValue( null, 'foo', '1' ) );
+
+		$result = new ApiResult( 8388608 );
+		$result2 = new ApiResult( 8388608 );
+		$result2->addValue( null, 'foo', 'bar' );
+		$result->addValue( null, 'baz', $result2 );
+		$this->assertSame( array( 'baz' => array( 'foo' => 'bar' ) ), $result->getResultData() );
+
+		$result = new ApiResult( 8388608 );
+		$result->addValue( null, 'foo', "foo\x80bar" );
+		$result->addValue( null, 'bar', "a\xcc\x81" );
+		$result->addValue( null, 'baz', 74 );
+		$this->assertSame( array(
+			'foo' => "foo\xef\xbf\xbdbar",
+			'bar' => "\xc3\xa1",
+			'baz' => 74,
+		), $result->getResultData() );
+	}
+
+	/**
+	 * @covers ApiResult
+	 */
+	public function testMetadata() {
+		$arr = array( 'foo' => array( 'bar' => array() ) );
+		$result = new ApiResult( 8388608 );
+		$result->addValue( null, 'foo', array( 'bar' => array() ) );
+
+		$expect = array(
+			'foo' => array(
+				'bar' => array(
+					ApiResult::META_INDEXED_TAG_NAME => 'ritn',
+					ApiResult::META_TYPE => 'default',
+				),
+				ApiResult::META_INDEXED_TAG_NAME => 'ritn',
+				ApiResult::META_TYPE => 'default',
+			),
+			ApiResult::META_SUBELEMENTS => array( 'foo', 'bar' ),
+			ApiResult::META_INDEXED_TAG_NAME => 'itn',
+			ApiResult::META_PRESERVE_KEYS => array( 'foo', 'bar' ),
+			ApiResult::META_TYPE => 'array',
+		);
+
+		ApiResult::setSubelementsList( $arr, 'foo' );
+		ApiResult::setSubelementsList( $arr, array( 'bar', 'baz' ) );
+		ApiResult::unsetSubelementsList( $arr, 'baz' );
+		ApiResult::setIndexedTagNameRecursive( $arr, 'ritn' );
+		ApiResult::setIndexedTagName( $arr, 'itn' );
+		ApiResult::setPreserveKeysList( $arr, 'foo' );
+		ApiResult::setPreserveKeysList( $arr, array( 'bar', 'baz' ) );
+		ApiResult::unsetPreserveKeysList( $arr, 'baz' );
+		ApiResult::setArrayTypeRecursive( $arr, 'default' );
+		ApiResult::setArrayType( $arr, 'array' );
+		$this->assertSame( $expect, $arr );
+
+		$result->addSubelementsList( null, 'foo' );
+		$result->addSubelementsList( null, array( 'bar', 'baz' ) );
+		$result->removeSubelementsList( null, 'baz' );
+		$result->addIndexedTagNameRecursive( null, 'ritn' );
+		$result->addIndexedTagName( null, 'itn' );
+		$result->addPreserveKeysList( null, 'foo' );
+		$result->addPreserveKeysList( null, array( 'bar', 'baz' ) );
+		$result->removePreserveKeysList( null, 'baz' );
+		$result->addArrayTypeRecursive( null, 'default' );
+		$result->addArrayType( null, 'array' );
+		$this->assertSame( $expect, $result->getResultData() );
+
+		$arr = array( 'foo' => array( 'bar' => array() ) );
+		$expect = array(
+			'foo' => array(
+				'bar' => array(
+					ApiResult::META_TYPE => 'kvp',
+					ApiResult::META_KVP_KEY_NAME => 'key',
+				),
+				ApiResult::META_TYPE => 'kvp',
+				ApiResult::META_KVP_KEY_NAME => 'key',
+			),
+			ApiResult::META_TYPE => 'BCkvp',
+			ApiResult::META_KVP_KEY_NAME => 'bc',
+		);
+		ApiResult::setArrayTypeRecursive( $arr, 'kvp', 'key' );
+		ApiResult::setArrayType( $arr, 'BCkvp', 'bc' );
+		$this->assertSame( $expect, $arr );
+	}
+
+	/**
+	 * @covers ApiResult
+	 */
+	public function testUtilityFunctions() {
+		$arr = array(
+			'foo' => array(
+				'bar' => array( '_dummy' => 'foobaz' ),
+				'bar2' => (object)array( '_dummy' => 'foobaz' ),
+				'x' => 'ok',
+				'_dummy' => 'foobaz',
+			),
+			'foo2' => (object)array(
+				'bar' => array( '_dummy' => 'foobaz' ),
+				'bar2' => (object)array( '_dummy' => 'foobaz' ),
+				'x' => 'ok',
+				'_dummy' => 'foobaz',
+			),
+			ApiResult::META_SUBELEMENTS => array( 'foo', 'bar' ),
+			ApiResult::META_INDEXED_TAG_NAME => 'itn',
+			ApiResult::META_PRESERVE_KEYS => array( 'foo', 'bar', '_dummy2', 0 ),
+			ApiResult::META_TYPE => 'array',
+			'_dummy' => 'foobaz',
+			'_dummy2' => 'foobaz!',
+		);
+		$this->assertEquals( array(
+			'foo' => array(
+				'bar' => array(),
+				'bar2' => (object)array(),
+				'x' => 'ok',
+			),
+			'foo2' => (object)array(
+				'bar' => array(),
+				'bar2' => (object)array(),
+				'x' => 'ok',
+			),
+			'_dummy2' => 'foobaz!',
+		), ApiResult::stripMetadata( $arr ), 'ApiResult::stripMetadata' );
+
+		$metadata = array();
+		$data = ApiResult::stripMetadataNonRecursive( $arr, $metadata );
+		$this->assertEquals( array(
+			'foo' => array(
+				'bar' => array( '_dummy' => 'foobaz' ),
+				'bar2' => (object)array( '_dummy' => 'foobaz' ),
+				'x' => 'ok',
+				'_dummy' => 'foobaz',
+			),
+			'foo2' => (object)array(
+				'bar' => array( '_dummy' => 'foobaz' ),
+				'bar2' => (object)array( '_dummy' => 'foobaz' ),
+				'x' => 'ok',
+				'_dummy' => 'foobaz',
+			),
+			'_dummy2' => 'foobaz!',
+		), $data, 'ApiResult::stripMetadataNonRecursive ($data)' );
+		$this->assertEquals( array(
+			ApiResult::META_SUBELEMENTS => array( 'foo', 'bar' ),
+			ApiResult::META_INDEXED_TAG_NAME => 'itn',
+			ApiResult::META_PRESERVE_KEYS => array( 'foo', 'bar', '_dummy2', 0 ),
+			ApiResult::META_TYPE => 'array',
+			'_dummy' => 'foobaz',
+		), $metadata, 'ApiResult::stripMetadataNonRecursive ($metadata)' );
+
+		$metadata = null;
+		$data = ApiResult::stripMetadataNonRecursive( (object)$arr, $metadata );
+		$this->assertEquals( (object)array(
+			'foo' => array(
+				'bar' => array( '_dummy' => 'foobaz' ),
+				'bar2' => (object)array( '_dummy' => 'foobaz' ),
+				'x' => 'ok',
+				'_dummy' => 'foobaz',
+			),
+			'foo2' => (object)array(
+				'bar' => array( '_dummy' => 'foobaz' ),
+				'bar2' => (object)array( '_dummy' => 'foobaz' ),
+				'x' => 'ok',
+				'_dummy' => 'foobaz',
+			),
+			'_dummy2' => 'foobaz!',
+		), $data, 'ApiResult::stripMetadataNonRecursive on object ($data)' );
+		$this->assertEquals( array(
+			ApiResult::META_SUBELEMENTS => array( 'foo', 'bar' ),
+			ApiResult::META_INDEXED_TAG_NAME => 'itn',
+			ApiResult::META_PRESERVE_KEYS => array( 'foo', 'bar', '_dummy2', 0 ),
+			ApiResult::META_TYPE => 'array',
+			'_dummy' => 'foobaz',
+		), $metadata, 'ApiResult::stripMetadataNonRecursive on object ($metadata)' );
+	}
+
+	/**
+	 * @covers ApiResult
+	 * @dataProvider provideTransformations
+	 * @param string $label
+	 * @param array $input
+	 * @param array $transforms
+	 * @param array|Exception $expect
+	 */
+	public function testTransformations( $label, $input, $transforms, $expect ) {
+		$result = new ApiResult( false );
+		$result->addValue( null, 'test', $input );
+
+		if ( $expect instanceof Exception ) {
+			try {
+				$output = $result->getResultData( 'test', $transforms );
+				$this->fail( 'Expected exception not thrown', $label );
+			} catch ( Exception $ex ) {
+				$this->assertEquals( $ex, $expect, $label );
+			}
+		} else {
+			$output = $result->getResultData( 'test', $transforms );
+			$this->assertEquals( $expect, $output, $label );
+		}
+	}
+
+	public function provideTransformations() {
+		$kvp = function ( $keyKey, $key, $valKey, $value ) {
+			return array(
+				$keyKey => $key,
+				$valKey => $value,
+				ApiResult::META_PRESERVE_KEYS => array( $keyKey ),
+				ApiResult::META_CONTENT => $valKey,
+				ApiResult::META_TYPE => 'assoc',
+			);
+		};
+		$typeArr = array(
+			'defaultArray' => array( 2 => 'a', 0 => 'b', 1 => 'c' ),
+			'defaultAssoc' => array( 'x' => 'a', 1 => 'b', 0 => 'c' ),
+			'defaultAssoc2' => array( 2 => 'a', 3 => 'b', 0 => 'c' ),
+			'array' => array( 'x' => 'a', 1 => 'b', 0 => 'c', ApiResult::META_TYPE => 'array' ),
+			'BCarray' => array( 'x' => 'a', 1 => 'b', 0 => 'c', ApiResult::META_TYPE => 'BCarray' ),
+			'BCassoc' => array( 'a', 'b', 'c', ApiResult::META_TYPE => 'BCassoc' ),
+			'assoc' => array( 2 => 'a', 0 => 'b', 1 => 'c', ApiResult::META_TYPE => 'assoc' ),
+			'kvp' => array( 'x' => 'a', 'y' => 'b', 'z' => array( 'c' ), ApiResult::META_TYPE => 'kvp' ),
+			'BCkvp' => array( 'x' => 'a', 'y' => 'b',
+				ApiResult::META_TYPE => 'BCkvp',
+				ApiResult::META_KVP_KEY_NAME => 'key',
+			),
+			'emptyDefault' => array( '_dummy' => 1 ),
+			'emptyAssoc' => array( '_dummy' => 1, ApiResult::META_TYPE => 'assoc' ),
+			'_dummy' => 1,
+			ApiResult::META_PRESERVE_KEYS => array( '_dummy' ),
+		);
+		$stripArr = array(
+			'foo' => array(
+				'bar' => array( '_dummy' => 'foobaz' ),
+				'baz' => array(
+					ApiResult::META_SUBELEMENTS => array( 'foo', 'bar' ),
+					ApiResult::META_INDEXED_TAG_NAME => 'itn',
+					ApiResult::META_PRESERVE_KEYS => array( 'foo', 'bar', '_dummy2', 0 ),
+					ApiResult::META_TYPE => 'array',
+				),
+				'x' => 'ok',
+				'_dummy' => 'foobaz',
+			),
+			ApiResult::META_SUBELEMENTS => array( 'foo', 'bar' ),
+			ApiResult::META_INDEXED_TAG_NAME => 'itn',
+			ApiResult::META_PRESERVE_KEYS => array( 'foo', 'bar', '_dummy2', 0 ),
+			ApiResult::META_TYPE => 'array',
+			'_dummy' => 'foobaz',
+			'_dummy2' => 'foobaz!',
+		);
+
+		return array(
+			array(
+				'BC: META_BC_BOOLS',
+				array(
+					'BCtrue' => true,
+					'BCfalse' => false,
+					'true' => true,
+					'false' => false,
+					ApiResult::META_BC_BOOLS => array( 0, 'true', 'false' ),
+				),
+				array( 'BC' => array() ),
+				array(
+					'BCtrue' => '',
+					'true' => true,
+					'false' => false,
+					ApiResult::META_BC_BOOLS => array( 0, 'true', 'false' ),
+				)
+			),
+			array(
+				'BC: META_BC_SUBELEMENTS',
+				array(
+					'bc' => 'foo',
+					'nobc' => 'bar',
+					ApiResult::META_BC_SUBELEMENTS => array( 'bc' ),
+				),
+				array( 'BC' => array() ),
+				array(
+					'bc' => array(
+						'*' => 'foo',
+						ApiResult::META_CONTENT => '*',
+						ApiResult::META_TYPE => 'assoc',
+					),
+					'nobc' => 'bar',
+					ApiResult::META_BC_SUBELEMENTS => array( 'bc' ),
+				),
+			),
+			array(
+				'BC: META_CONTENT',
+				array(
+					'content' => '!!!',
+					ApiResult::META_CONTENT => 'content',
+				),
+				array( 'BC' => array() ),
+				array(
+					'*' => '!!!',
+					ApiResult::META_CONTENT => '*',
+				),
+			),
+			array(
+				'BC: BCkvp type',
+				array(
+					'foo' => 'foo value',
+					'bar' => 'bar value',
+					'_baz' => 'baz value',
+					ApiResult::META_TYPE => 'BCkvp',
+					ApiResult::META_KVP_KEY_NAME => 'key',
+					ApiResult::META_PRESERVE_KEYS => array( '_baz' ),
+				),
+				array( 'BC' => array() ),
+				array(
+					$kvp( 'key', 'foo', '*', 'foo value' ),
+					$kvp( 'key', 'bar', '*', 'bar value' ),
+					$kvp( 'key', '_baz', '*', 'baz value' ),
+					ApiResult::META_TYPE => 'array',
+					ApiResult::META_KVP_KEY_NAME => 'key',
+					ApiResult::META_PRESERVE_KEYS => array( '_baz' ),
+				),
+			),
+			array(
+				'BC: BCarray type',
+				array(
+					ApiResult::META_TYPE => 'BCarray',
+				),
+				array( 'BC' => array() ),
+				array(
+					ApiResult::META_TYPE => 'default',
+				),
+			),
+			array(
+				'BC: BCassoc type',
+				array(
+					ApiResult::META_TYPE => 'BCassoc',
+				),
+				array( 'BC' => array() ),
+				array(
+					ApiResult::META_TYPE => 'default',
+				),
+			),
+			array(
+				'BC: BCkvp exception',
+				array(
+					ApiResult::META_TYPE => 'BCkvp',
+				),
+				array( 'BC' => array() ),
+				new UnexpectedValueException(
+					'Type "BCkvp" used without setting ApiResult::META_KVP_KEY_NAME metadata item'
+				),
+			),
+			array(
+				'BC: nobool, no*, nosub',
+				array(
+					'true' => true,
+					'false' => false,
+					'content' => 'content',
+					ApiResult::META_CONTENT => 'content',
+					'bc' => 'foo',
+					ApiResult::META_BC_SUBELEMENTS => array( 'bc' ),
+					'BCarray' => array( ApiResult::META_TYPE => 'BCarray' ),
+					'BCassoc' => array( ApiResult::META_TYPE => 'BCassoc' ),
+					'BCkvp' => array(
+						'foo' => 'foo value',
+						'bar' => 'bar value',
+						'_baz' => 'baz value',
+						ApiResult::META_TYPE => 'BCkvp',
+						ApiResult::META_KVP_KEY_NAME => 'key',
+						ApiResult::META_PRESERVE_KEYS => array( '_baz' ),
+					),
+				),
+				array( 'BC' => array( 'nobool', 'no*', 'nosub' ) ),
+				array(
+					'true' => true,
+					'false' => false,
+					'content' => 'content',
+					'bc' => 'foo',
+					'BCarray' => array( ApiResult::META_TYPE => 'default' ),
+					'BCassoc' => array( ApiResult::META_TYPE => 'default' ),
+					'BCkvp' => array(
+						$kvp( 'key', 'foo', '*', 'foo value' ),
+						$kvp( 'key', 'bar', '*', 'bar value' ),
+						$kvp( 'key', '_baz', '*', 'baz value' ),
+						ApiResult::META_TYPE => 'array',
+						ApiResult::META_KVP_KEY_NAME => 'key',
+						ApiResult::META_PRESERVE_KEYS => array( '_baz' ),
+					),
+					ApiResult::META_CONTENT => 'content',
+					ApiResult::META_BC_SUBELEMENTS => array( 'bc' ),
+				),
+			),
+
+			array(
+				'Types: Normal transform',
+				$typeArr,
+				array( 'Types' => array() ),
+				array(
+					'defaultArray' => array( 'b', 'c', 'a', ApiResult::META_TYPE => 'array' ),
+					'defaultAssoc' => array( 'x' => 'a', 1 => 'b', 0 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'defaultAssoc2' => array( 2 => 'a', 3 => 'b', 0 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'array' => array( 'a', 'c', 'b', ApiResult::META_TYPE => 'array' ),
+					'BCarray' => array( 'a', 'c', 'b', ApiResult::META_TYPE => 'array' ),
+					'BCassoc' => array( 'a', 'b', 'c', ApiResult::META_TYPE => 'assoc' ),
+					'assoc' => array( 2 => 'a', 0 => 'b', 1 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'kvp' => array( 'x' => 'a', 'y' => 'b',
+						'z' => array( 'c', ApiResult::META_TYPE => 'array' ),
+						ApiResult::META_TYPE => 'assoc'
+					),
+					'BCkvp' => array( 'x' => 'a', 'y' => 'b',
+						ApiResult::META_TYPE => 'assoc',
+						ApiResult::META_KVP_KEY_NAME => 'key',
+					),
+					'emptyDefault' => array( '_dummy' => 1, ApiResult::META_TYPE => 'array' ),
+					'emptyAssoc' => array( '_dummy' => 1, ApiResult::META_TYPE => 'assoc' ),
+					'_dummy' => 1,
+					ApiResult::META_PRESERVE_KEYS => array( '_dummy' ),
+					ApiResult::META_TYPE => 'assoc',
+				),
+			),
+			array(
+				'Types: AssocAsObject',
+				$typeArr,
+				array( 'Types' => array( 'AssocAsObject' => true ) ),
+				(object)array(
+					'defaultArray' => array( 'b', 'c', 'a', ApiResult::META_TYPE => 'array' ),
+					'defaultAssoc' => (object)array( 'x' => 'a', 1 => 'b', 0 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'defaultAssoc2' => (object)array( 2 => 'a', 3 => 'b', 0 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'array' => array( 'a', 'c', 'b', ApiResult::META_TYPE => 'array' ),
+					'BCarray' => array( 'a', 'c', 'b', ApiResult::META_TYPE => 'array' ),
+					'BCassoc' => (object)array( 'a', 'b', 'c', ApiResult::META_TYPE => 'assoc' ),
+					'assoc' => (object)array( 2 => 'a', 0 => 'b', 1 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'kvp' => (object)array( 'x' => 'a', 'y' => 'b',
+						'z' => array( 'c', ApiResult::META_TYPE => 'array' ),
+						ApiResult::META_TYPE => 'assoc'
+					),
+					'BCkvp' => (object)array( 'x' => 'a', 'y' => 'b',
+						ApiResult::META_TYPE => 'assoc',
+						ApiResult::META_KVP_KEY_NAME => 'key',
+					),
+					'emptyDefault' => array( '_dummy' => 1, ApiResult::META_TYPE => 'array' ),
+					'emptyAssoc' => (object)array( '_dummy' => 1, ApiResult::META_TYPE => 'assoc' ),
+					'_dummy' => 1,
+					ApiResult::META_PRESERVE_KEYS => array( '_dummy' ),
+					ApiResult::META_TYPE => 'assoc',
+				),
+			),
+			array(
+				'Types: ArmorKVP',
+				$typeArr,
+				array( 'Types' => array( 'ArmorKVP' => 'name' ) ),
+				array(
+					'defaultArray' => array( 'b', 'c', 'a', ApiResult::META_TYPE => 'array' ),
+					'defaultAssoc' => array( 'x' => 'a', 1 => 'b', 0 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'defaultAssoc2' => array( 2 => 'a', 3 => 'b', 0 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'array' => array( 'a', 'c', 'b', ApiResult::META_TYPE => 'array' ),
+					'BCarray' => array( 'a', 'c', 'b', ApiResult::META_TYPE => 'array' ),
+					'BCassoc' => array( 'a', 'b', 'c', ApiResult::META_TYPE => 'assoc' ),
+					'assoc' => array( 2 => 'a', 0 => 'b', 1 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'kvp' => array(
+						$kvp( 'name', 'x', 'value', 'a' ),
+						$kvp( 'name', 'y', 'value', 'b' ),
+						$kvp( 'name', 'z', 'value', array( 'c', ApiResult::META_TYPE => 'array' ) ),
+						ApiResult::META_TYPE => 'array'
+					),
+					'BCkvp' => array(
+						$kvp( 'key', 'x', 'value', 'a' ),
+						$kvp( 'key', 'y', 'value', 'b' ),
+						ApiResult::META_TYPE => 'array',
+						ApiResult::META_KVP_KEY_NAME => 'key',
+					),
+					'emptyDefault' => array( '_dummy' => 1, ApiResult::META_TYPE => 'array' ),
+					'emptyAssoc' => array( '_dummy' => 1, ApiResult::META_TYPE => 'assoc' ),
+					'_dummy' => 1,
+					ApiResult::META_PRESERVE_KEYS => array( '_dummy' ),
+					ApiResult::META_TYPE => 'assoc',
+				),
+			),
+			array(
+				'Types: ArmorKVP + BC',
+				$typeArr,
+				array( 'BC' => array(), 'Types' => array( 'ArmorKVP' => 'name' ) ),
+				array(
+					'defaultArray' => array( 'b', 'c', 'a', ApiResult::META_TYPE => 'array' ),
+					'defaultAssoc' => array( 'x' => 'a', 1 => 'b', 0 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'defaultAssoc2' => array( 2 => 'a', 3 => 'b', 0 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'array' => array( 'a', 'c', 'b', ApiResult::META_TYPE => 'array' ),
+					'BCarray' => array( 'x' => 'a', 1 => 'b', 0 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'BCassoc' => array( 'a', 'b', 'c', ApiResult::META_TYPE => 'array' ),
+					'assoc' => array( 2 => 'a', 0 => 'b', 1 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'kvp' => array(
+						$kvp( 'name', 'x', '*', 'a' ),
+						$kvp( 'name', 'y', '*', 'b' ),
+						$kvp( 'name', 'z', '*', array( 'c', ApiResult::META_TYPE => 'array' ) ),
+						ApiResult::META_TYPE => 'array'
+					),
+					'BCkvp' => array(
+						$kvp( 'key', 'x', '*', 'a' ),
+						$kvp( 'key', 'y', '*', 'b' ),
+						ApiResult::META_TYPE => 'array',
+						ApiResult::META_KVP_KEY_NAME => 'key',
+					),
+					'emptyDefault' => array( '_dummy' => 1, ApiResult::META_TYPE => 'array' ),
+					'emptyAssoc' => array( '_dummy' => 1, ApiResult::META_TYPE => 'assoc' ),
+					'_dummy' => 1,
+					ApiResult::META_PRESERVE_KEYS => array( '_dummy' ),
+					ApiResult::META_TYPE => 'assoc',
+				),
+			),
+			array(
+				'Types: ArmorKVP + AssocAsObject',
+				$typeArr,
+				array( 'Types' => array( 'ArmorKVP' => 'name', 'AssocAsObject' => true ) ),
+				(object)array(
+					'defaultArray' => array( 'b', 'c', 'a', ApiResult::META_TYPE => 'array' ),
+					'defaultAssoc' => (object)array( 'x' => 'a', 1 => 'b', 0 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'defaultAssoc2' => (object)array( 2 => 'a', 3 => 'b', 0 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'array' => array( 'a', 'c', 'b', ApiResult::META_TYPE => 'array' ),
+					'BCarray' => array( 'a', 'c', 'b', ApiResult::META_TYPE => 'array' ),
+					'BCassoc' => (object)array( 'a', 'b', 'c', ApiResult::META_TYPE => 'assoc' ),
+					'assoc' => (object)array( 2 => 'a', 0 => 'b', 1 => 'c', ApiResult::META_TYPE => 'assoc' ),
+					'kvp' => array(
+						(object)$kvp( 'name', 'x', 'value', 'a' ),
+						(object)$kvp( 'name', 'y', 'value', 'b' ),
+						(object)$kvp( 'name', 'z', 'value', array( 'c', ApiResult::META_TYPE => 'array' ) ),
+						ApiResult::META_TYPE => 'array'
+					),
+					'BCkvp' => array(
+						(object)$kvp( 'key', 'x', 'value', 'a' ),
+						(object)$kvp( 'key', 'y', 'value', 'b' ),
+						ApiResult::META_TYPE => 'array',
+						ApiResult::META_KVP_KEY_NAME => 'key',
+					),
+					'emptyDefault' => array( '_dummy' => 1, ApiResult::META_TYPE => 'array' ),
+					'emptyAssoc' => (object)array( '_dummy' => 1, ApiResult::META_TYPE => 'assoc' ),
+					'_dummy' => 1,
+					ApiResult::META_PRESERVE_KEYS => array( '_dummy' ),
+					ApiResult::META_TYPE => 'assoc',
+				),
+			),
+			array(
+				'Types: BCkvp exception',
+				array(
+					ApiResult::META_TYPE => 'BCkvp',
+				),
+				array( 'Types' => array() ),
+				new UnexpectedValueException(
+					'Type "BCkvp" used without setting ApiResult::META_KVP_KEY_NAME metadata item'
+				),
+			),
+
+			array(
+				'Strip: With ArmorKVP + AssocAsObject transforms',
+				$typeArr,
+				array( 'Types' => array( 'ArmorKVP' => 'name', 'AssocAsObject' => true ), 'Strip' => 'all' ),
+				(object)array(
+					'defaultArray' => array( 'b', 'c', 'a' ),
+					'defaultAssoc' => (object)array( 'x' => 'a', 1 => 'b', 0 => 'c' ),
+					'defaultAssoc2' => (object)array( 2 => 'a', 3 => 'b', 0 => 'c' ),
+					'array' => array( 'a', 'c', 'b' ),
+					'BCarray' => array( 'a', 'c', 'b' ),
+					'BCassoc' => (object)array( 'a', 'b', 'c' ),
+					'assoc' => (object)array( 2 => 'a', 0 => 'b', 1 => 'c' ),
+					'kvp' => array(
+						(object)array( 'name' => 'x', 'value' => 'a' ),
+						(object)array( 'name' => 'y', 'value' => 'b' ),
+						(object)array( 'name' => 'z', 'value' => array( 'c' ) ),
+					),
+					'BCkvp' => array(
+						(object)array( 'key' => 'x', 'value' => 'a' ),
+						(object)array( 'key' => 'y', 'value' => 'b' ),
+					),
+					'emptyDefault' => array(),
+					'emptyAssoc' => (object)array(),
+					'_dummy' => 1,
+				),
+			),
+
+			array(
+				'Strip: all',
+				$stripArr,
+				array( 'Strip' => 'all' ),
+				array(
+					'foo' => array(
+						'bar' => array(),
+						'baz' => array(),
+						'x' => 'ok',
+					),
+					'_dummy2' => 'foobaz!',
+				),
+			),
+			array(
+				'Strip: base',
+				$stripArr,
+				array( 'Strip' => 'base' ),
+				array(
+					'foo' => array(
+						'bar' => array( '_dummy' => 'foobaz' ),
+						'baz' => array(
+							ApiResult::META_SUBELEMENTS => array( 'foo', 'bar' ),
+							ApiResult::META_INDEXED_TAG_NAME => 'itn',
+							ApiResult::META_PRESERVE_KEYS => array( 'foo', 'bar', '_dummy2', 0 ),
+							ApiResult::META_TYPE => 'array',
+						),
+						'x' => 'ok',
+						'_dummy' => 'foobaz',
+					),
+					'_dummy2' => 'foobaz!',
+				),
+			),
+			array(
+				'Strip: bc',
+				$stripArr,
+				array( 'Strip' => 'bc' ),
+				array(
+					'foo' => array(
+						'bar' => array(),
+						'baz' => array(
+							ApiResult::META_SUBELEMENTS => array( 'foo', 'bar' ),
+							ApiResult::META_INDEXED_TAG_NAME => 'itn',
+						),
+						'x' => 'ok',
+					),
+					'_dummy2' => 'foobaz!',
+					ApiResult::META_SUBELEMENTS => array( 'foo', 'bar' ),
+					ApiResult::META_INDEXED_TAG_NAME => 'itn',
+				),
+			),
+
+			array(
+				'Custom transform',
+				array(
+					'foo' => '?',
+					'bar' => '?',
+					'_dummy' => '?',
+					'_dummy2' => '?',
+					'_dummy3' => '?',
+					ApiResult::META_CONTENT => 'foo',
+					ApiResult::META_PRESERVE_KEYS => array( '_dummy2', '_dummy3' ),
+				),
+				array(
+					'Custom' => array( $this, 'customTransform' ),
+					'BC' => array(),
+					'Types' => array(),
+					'Strip' => 'all'
+				),
+				array(
+					'*' => 'FOO',
+					'bar' => 'BAR',
+					'baz' => array( 'a', 'b' ),
+					'_dummy2' => '_DUMMY2',
+					'_dummy3' => '_DUMMY3',
+					ApiResult::META_CONTENT => 'bar',
+				),
+			),
+		);
+
+	}
+
+	/**
+	 * Custom transformer for testTransformations
+	 * @param array &$data
+	 * @param array &$metadata
+	 */
+	public function customTransform( &$data, &$metadata ) {
+		// Prevent recursion
+		if ( isset( $metadata['_added'] ) ) {
+			$metadata[ApiResult::META_TYPE] = 'array';
+			return;
+		}
+
+		foreach ( $data as $k => $v ) {
+			$data[$k] = strtoupper( $k );
+		}
+		$data['baz'] = array( '_added' => 1, 'z' => 'b', 'y' => 'a' );
+		$metadata[ApiResult::META_PRESERVE_KEYS][0] = '_dummy';
+		$data[ApiResult::META_CONTENT] = 'bar';
+	}
+
+	/**
+	 * @covers ApiResult
+	 */
+	public function testDeprecatedFunctions() {
+		// Ignore ApiResult deprecation warnings during this test
+		set_error_handler( function ( $errno, $errstr ) use ( &$warnings ) {
+			if ( preg_match( '/Use of ApiResult::\S+ was deprecated in MediaWiki \d+.\d+\./', $errstr ) ) {
+				return true;
+			}
+			return false;
+		} );
+		$reset = new ScopedCallback( 'restore_error_handler' );
+
+		$context = new DerivativeContext( RequestContext::getMain() );
+		$context->setConfig( new HashConfig( array(
+			'APIModules' => array(),
+			'APIFormatModules' => array(),
+			'APIMaxResultSize' => 42,
+		) ) );
+		$main = new ApiMain( $context );
+		$result = TestingAccessWrapper::newFromObject( new ApiResult( $main ) );
+		$this->assertSame( 42, $result->maxSize );
+		$this->assertSame( $main->getErrorFormatter(), $result->errorFormatter );
+		$this->assertSame( $main, $result->mainForContinuation );
+
+		$result = new ApiResult( 8388608 );
+
+		$result->addContentValue( null, 'test', 'content' );
+		$result->addContentValue( array( 'foo', 'bar' ), 'test', 'content' );
+		$result->addIndexedTagName( null, 'itn' );
+		$result->addSubelementsList( null, array( 'sub' ) );
+		$this->assertSame( array(
+			'foo' => array(
+				'bar' => array(
+					'*' => 'content',
+				),
+			),
+			'*' => 'content',
+		), $result->getData() );
+		$result->setRawMode();
+		$this->assertSame( array(
+			'foo' => array(
+				'bar' => array(
+					'*' => 'content',
+				),
+			),
+			'*' => 'content',
+			'_element' => 'itn',
+			'_subelements' => array( 'sub' ),
+		), $result->getData() );
+
+		$arr = array();
+		ApiResult::setContent( $arr, 'value' );
+		ApiResult::setContent( $arr, 'value2', 'foobar' );
+		$this->assertSame( array(
+			ApiResult::META_CONTENT => 'content',
+			'content' => 'value',
+			'foobar' => array(
+				ApiResult::META_CONTENT => 'content',
+				'content' => 'value2',
+			),
+		), $arr );
+
+		$result = new ApiResult( 3 );
+		$formatter = new ApiErrorFormatter_BackCompat( $result );
+		$result->setErrorFormatter( $formatter );
+		$result->disableSizeCheck();
+		$this->assertTrue( $result->addValue( null, 'foo', '1234567890' ) );
+		$result->enableSizeCheck();
+		$this->assertSame( 0, $result->getSize() );
+		$this->assertFalse( $result->addValue( null, 'foo', '1234567890' ) );
+
+		$arr = array( 'foo' => array( 'bar' => 1 ) );
+		$result->setIndexedTagName_recursive( $arr, 'itn' );
+		$this->assertSame( array(
+			'foo' => array(
+				'bar' => 1,
+				ApiResult::META_INDEXED_TAG_NAME => 'itn'
+			),
+		), $arr );
+
+		$status = Status::newGood();
+		$status->fatal( 'parentheses', '1' );
+		$status->fatal( 'parentheses', '2' );
+		$status->warning( 'parentheses', '3' );
+		$status->warning( 'parentheses', '4' );
+		$this->assertSame( array(
+			array(
+				'type' => 'error',
+				'message' => 'parentheses',
+				'params' => array(
+					0 => '1',
+					ApiResult::META_INDEXED_TAG_NAME => 'param',
+				),
+			),
+			array(
+				'type' => 'error',
+				'message' => 'parentheses',
+				'params' => array(
+					0 => '2',
+					ApiResult::META_INDEXED_TAG_NAME => 'param',
+				),
+			),
+			ApiResult::META_INDEXED_TAG_NAME => 'error',
+		), $result->convertStatusToArray( $status, 'error' ) );
+		$this->assertSame( array(
+			array(
+				'type' => 'warning',
+				'message' => 'parentheses',
+				'params' => array(
+					0 => '3',
+					ApiResult::META_INDEXED_TAG_NAME => 'param',
+				),
+			),
+			array(
+				'type' => 'warning',
+				'message' => 'parentheses',
+				'params' => array(
+					0 => '4',
+					ApiResult::META_INDEXED_TAG_NAME => 'param',
+				),
+			),
+			ApiResult::META_INDEXED_TAG_NAME => 'warning',
+		), $result->convertStatusToArray( $status, 'warning' ) );
+	}
+
+	/**
+	 * @covers ApiResult
+	 */
+	public function testDeprecatedContinuation() {
+		// Ignore ApiResult deprecation warnings during this test
+		set_error_handler( function ( $errno, $errstr ) use ( &$warnings ) {
+			if ( preg_match( '/Use of ApiResult::\S+ was deprecated in MediaWiki \d+.\d+\./', $errstr ) ) {
+				return true;
+			}
+			return false;
+		} );
+
+		$reset = new ScopedCallback( 'restore_error_handler' );
+		$allModules = array(
+			new MockApiQueryBase( 'mock1' ),
+			new MockApiQueryBase( 'mock2' ),
+			new MockApiQueryBase( 'mocklist' ),
+		);
+		$generator = new MockApiQueryBase( 'generator' );
+
+		$main = new ApiMain( RequestContext::getMain() );
+		$result = new ApiResult( 8388608 );
+		$result->setMainForContinuation( $main );
+		$ret = $result->beginContinuation( null, $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( array( false, $allModules ), $ret );
+		$result->setContinueParam( $allModules[0], 'm1continue', array( 1, 2 ) );
+		$result->setContinueParam( $allModules[2], 'mlcontinue', 2 );
+		$result->setGeneratorContinueParam( $generator, 'gcontinue', 3 );
+		$result->endContinuation( 'raw' );
+		$result->endContinuation( 'standard' );
+		$this->assertSame( array(
+			'mlcontinue' => 2,
+			'm1continue' => '1|2',
+			'continue' => '||mock2',
+		), $result->getResultData( 'continue' ) );
+		$this->assertSame( null, $result->getResultData( 'batchcomplete' ) );
+		$this->assertSame( array(
+			'mock1' => array( 'm1continue' => '1|2' ),
+			'mocklist' => array( 'mlcontinue' => 2 ),
+			'generator' => array( 'gcontinue' => 3 ),
+		), $result->getResultData( 'query-continue' ) );
+		$main->setContinuationManager( null );
+
+		$result = new ApiResult( 8388608 );
+		$result->setMainForContinuation( $main );
+		$ret = $result->beginContinuation( null, $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( array( false, $allModules ), $ret );
+		$result->setContinueParam( $allModules[0], 'm1continue', array( 1, 2 ) );
+		$result->setGeneratorContinueParam( $generator, 'gcontinue', array( 3, 4 ) );
+		$result->endContinuation( 'raw' );
+		$result->endContinuation( 'standard' );
+		$this->assertSame( array(
+			'm1continue' => '1|2',
+			'continue' => '||mock2|mocklist',
+		), $result->getResultData( 'continue' ) );
+		$this->assertSame( null, $result->getResultData( 'batchcomplete' ) );
+		$this->assertSame( array(
+			'mock1' => array( 'm1continue' => '1|2' ),
+			'generator' => array( 'gcontinue' => '3|4' ),
+		), $result->getResultData( 'query-continue' ) );
+		$main->setContinuationManager( null );
+
+		$result = new ApiResult( 8388608 );
+		$result->setMainForContinuation( $main );
+		$ret = $result->beginContinuation( null, $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( array( false, $allModules ), $ret );
+		$result->setContinueParam( $allModules[2], 'mlcontinue', 2 );
+		$result->setGeneratorContinueParam( $generator, 'gcontinue', 3 );
+		$result->endContinuation( 'raw' );
+		$result->endContinuation( 'standard' );
+		$this->assertSame( array(
+			'mlcontinue' => 2,
+			'gcontinue' => 3,
+			'continue' => 'gcontinue||',
+		), $result->getResultData( 'continue' ) );
+		$this->assertSame( '', $result->getResultData( 'batchcomplete' ) );
+		$this->assertSame( array(
+			'mocklist' => array( 'mlcontinue' => 2 ),
+			'generator' => array( 'gcontinue' => 3 ),
+		), $result->getResultData( 'query-continue' ) );
+		$main->setContinuationManager( null );
+
+		$result = new ApiResult( 8388608 );
+		$result->setMainForContinuation( $main );
+		$ret = $result->beginContinuation( null, $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( array( false, $allModules ), $ret );
+		$result->setGeneratorContinueParam( $generator, 'gcontinue', 3 );
+		$result->endContinuation( 'raw' );
+		$result->endContinuation( 'standard' );
+		$this->assertSame( array(
+			'gcontinue' => 3,
+			'continue' => 'gcontinue||mocklist',
+		), $result->getResultData( 'continue' ) );
+		$this->assertSame( '', $result->getResultData( 'batchcomplete' ) );
+		$this->assertSame( array(
+			'generator' => array( 'gcontinue' => 3 ),
+		), $result->getResultData( 'query-continue' ) );
+		$main->setContinuationManager( null );
+
+		$result = new ApiResult( 8388608 );
+		$result->setMainForContinuation( $main );
+		$ret = $result->beginContinuation( null, $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( array( false, $allModules ), $ret );
+		$result->setContinueParam( $allModules[0], 'm1continue', array( 1, 2 ) );
+		$result->setContinueParam( $allModules[2], 'mlcontinue', 2 );
+		$result->endContinuation( 'raw' );
+		$result->endContinuation( 'standard' );
+		$this->assertSame( array(
+			'mlcontinue' => 2,
+			'm1continue' => '1|2',
+			'continue' => '||mock2',
+		), $result->getResultData( 'continue' ) );
+		$this->assertSame( null, $result->getResultData( 'batchcomplete' ) );
+		$this->assertSame( array(
+			'mock1' => array( 'm1continue' => '1|2' ),
+			'mocklist' => array( 'mlcontinue' => 2 ),
+		), $result->getResultData( 'query-continue' ) );
+		$main->setContinuationManager( null );
+
+		$result = new ApiResult( 8388608 );
+		$result->setMainForContinuation( $main );
+		$ret = $result->beginContinuation( null, $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( array( false, $allModules ), $ret );
+		$result->setContinueParam( $allModules[0], 'm1continue', array( 1, 2 ) );
+		$result->endContinuation( 'raw' );
+		$result->endContinuation( 'standard' );
+		$this->assertSame( array(
+			'm1continue' => '1|2',
+			'continue' => '||mock2|mocklist',
+		), $result->getResultData( 'continue' ) );
+		$this->assertSame( null, $result->getResultData( 'batchcomplete' ) );
+		$this->assertSame( array(
+			'mock1' => array( 'm1continue' => '1|2' ),
+		), $result->getResultData( 'query-continue' ) );
+		$main->setContinuationManager( null );
+
+		$result = new ApiResult( 8388608 );
+		$result->setMainForContinuation( $main );
+		$ret = $result->beginContinuation( null, $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( array( false, $allModules ), $ret );
+		$result->setContinueParam( $allModules[2], 'mlcontinue', 2 );
+		$result->endContinuation( 'raw' );
+		$result->endContinuation( 'standard' );
+		$this->assertSame( array(
+			'mlcontinue' => 2,
+			'continue' => '-||mock1|mock2',
+		), $result->getResultData( 'continue' ) );
+		$this->assertSame( '', $result->getResultData( 'batchcomplete' ) );
+		$this->assertSame( array(
+			'mocklist' => array( 'mlcontinue' => 2 ),
+		), $result->getResultData( 'query-continue' ) );
+		$main->setContinuationManager( null );
+
+		$result = new ApiResult( 8388608 );
+		$result->setMainForContinuation( $main );
+		$ret = $result->beginContinuation( null, $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame( array( false, $allModules ), $ret );
+		$result->endContinuation( 'raw' );
+		$result->endContinuation( 'standard' );
+		$this->assertSame( null, $result->getResultData( 'continue' ) );
+		$this->assertSame( '', $result->getResultData( 'batchcomplete' ) );
+		$this->assertSame( null, $result->getResultData( 'query-continue' ) );
+		$main->setContinuationManager( null );
+
+		$result = new ApiResult( 8388608 );
+		$result->setMainForContinuation( $main );
+		$ret = $result->beginContinuation( '||mock2', $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame(
+			array( false, array_values( array_diff_key( $allModules, array( 1 => 1 ) ) ) ),
+			$ret
+		);
+		$main->setContinuationManager( null );
+
+		$result = new ApiResult( 8388608 );
+		$result->setMainForContinuation( $main );
+		$ret = $result->beginContinuation( '-||', $allModules, array( 'mock1', 'mock2' ) );
+		$this->assertSame(
+			array( true, array_values( array_diff_key( $allModules, array( 0 => 0, 1 => 1 ) ) ) ),
+			$ret
+		);
+		$main->setContinuationManager( null );
+
+		$result = new ApiResult( 8388608 );
+		$result->setMainForContinuation( $main );
+		try {
+			$result->beginContinuation( 'foo', $allModules, array( 'mock1', 'mock2' ) );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( UsageException $ex ) {
+			$this->assertSame(
+				'Invalid continue param. You should pass the original value returned by the previous query',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+		$main->setContinuationManager( null );
+
+		$result = new ApiResult( 8388608 );
+		$result->setMainForContinuation( $main );
+		$result->beginContinuation( '||mock2', array_slice( $allModules, 0, 2 ), array( 'mock1', 'mock2' ) );
+		try {
+			$result->setContinueParam( $allModules[1], 'm2continue', 1 );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( UnexpectedValueException $ex ) {
+			$this->assertSame(
+				'Module \'mock2\' was not supposed to have been executed, but it was executed anyway',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+		try {
+			$result->setContinueParam( $allModules[2], 'mlcontinue', 1 );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( UnexpectedValueException $ex ) {
+			$this->assertSame(
+				'Module \'mocklist\' called ApiContinuationManager::addContinueParam but was not passed to ApiContinuationManager::__construct',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+		$main->setContinuationManager( null );
+
+	}
+
+	public function testObjectSerialization() {
+		$arr = array();
+		ApiResult::setValue( $arr, 'foo', (object)array( 'a' => 1, 'b' => 2 ) );
+		$this->assertSame( array(
+			'a' => 1,
+			'b' => 2,
+			ApiResult::META_TYPE => 'assoc',
+		), $arr['foo'] );
+
+		$arr = array();
+		ApiResult::setValue( $arr, 'foo', new ApiResultTestStringifiableObject() );
+		$this->assertSame( 'Ok', $arr['foo'] );
+
+		$arr = array();
+		ApiResult::setValue( $arr, 'foo', new ApiResultTestSerializableObject( 'Ok' ) );
+		$this->assertSame( 'Ok', $arr['foo'] );
+
+		try {
+			$arr = array();
+			ApiResult::setValue( $arr, 'foo',  new ApiResultTestSerializableObject(
+				new ApiResultTestStringifiableObject()
+			) );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( UnexpectedValueException $ex ) {
+			$this->assertSame(
+				'ApiResultTestSerializableObject::serializeForApiResult() returned an object of class ApiResultTestStringifiableObject',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+
+		try {
+			$arr = array();
+			ApiResult::setValue( $arr, 'foo',  new ApiResultTestSerializableObject( NAN ) );
+			$this->fail( 'Expected exception not thrown' );
+		} catch ( UnexpectedValueException $ex ) {
+			$this->assertSame(
+				'ApiResultTestSerializableObject::serializeForApiResult() returned an invalid value: Cannot add non-finite floats to ApiResult',
+				$ex->getMessage(),
+				'Expected exception'
+			);
+		}
+
+		$arr = array();
+		ApiResult::setValue( $arr, 'foo',  new ApiResultTestSerializableObject(
+			array(
+				'one' => new ApiResultTestStringifiableObject( '1' ),
+				'two' => new ApiResultTestSerializableObject( 2 ),
+			)
+		) );
+		$this->assertSame( array(
+			'one' => '1',
+			'two' => 2,
+		), $arr['foo'] );
+	}
+
+}
+
+class ApiResultTestStringifiableObject {
+	private $ret;
+
+	public function __construct( $ret = 'Ok' ) {
+		$this->ret = $ret;
+	}
+
+	public function __toString() {
+		return $this->ret;
+	}
+}
+
+class ApiResultTestSerializableObject {
+	private $ret;
+
+	public function __construct( $ret ) {
+		$this->ret = $ret;
+	}
+
+	public function __toString() {
+		return "Fail";
+	}
+
+	public function serializeForApiResult() {
+		return $this->ret;
+	}
+}
diff --git a/tests/phpunit/includes/api/ApiTestCase.php b/tests/phpunit/includes/api/ApiTestCase.php
index 8c27b1018a2c..da62bb0a9797 100644
--- a/tests/phpunit/includes/api/ApiTestCase.php
+++ b/tests/phpunit/includes/api/ApiTestCase.php
@@ -116,7 +116,7 @@ abstract class ApiTestCase extends MediaWikiLangTestCase {
 
 		// construct result
 		$results = array(
-			$module->getResultData(),
+			$module->getResult()->getResultData( null, array( 'Strip' => 'all' ) ),
 			$context->getRequest(),
 			$context->getRequest()->getSessionArray()
 		);
diff --git a/tests/phpunit/includes/api/MockApi.php b/tests/phpunit/includes/api/MockApi.php
index d94aa2cda562..516da0c8ecc3 100644
--- a/tests/phpunit/includes/api/MockApi.php
+++ b/tests/phpunit/includes/api/MockApi.php
@@ -4,9 +4,6 @@ class MockApi extends ApiBase {
 	public function execute() {
 	}
 
-	public function getVersion() {
-	}
-
 	public function __construct() {
 	}
 
diff --git a/tests/phpunit/includes/api/MockApiQueryBase.php b/tests/phpunit/includes/api/MockApiQueryBase.php
index 4bede51915dd..f5b50e5a5919 100644
--- a/tests/phpunit/includes/api/MockApiQueryBase.php
+++ b/tests/phpunit/includes/api/MockApiQueryBase.php
@@ -1,11 +1,15 @@
 <?php
 class MockApiQueryBase extends ApiQueryBase {
+	private $name;
+
 	public function execute() {
 	}
 
-	public function getVersion() {
+	public function __construct( $name = 'mock' ) {
+		$this->name = $name;
 	}
 
-	public function __construct() {
+	public function getModuleName() {
+		return $this->name;
 	}
 }
diff --git a/tests/phpunit/includes/api/format/ApiFormatDbgTest.php b/tests/phpunit/includes/api/format/ApiFormatDbgTest.php
index 1e4ea53ccc4c..3fcfc73fc60d 100644
--- a/tests/phpunit/includes/api/format/ApiFormatDbgTest.php
+++ b/tests/phpunit/includes/api/format/ApiFormatDbgTest.php
@@ -16,8 +16,12 @@ class ApiFormatDbgTest extends ApiFormatTestBase {
 		return array(
 			// Basic types
 			array( array( null ), "array ({$warning}\n  0 => NULL,\n)" ),
-			array( array( true ), "array ({$warning}\n  0 => true,\n)" ),
-			array( array( false ), "array ({$warning}\n  0 => false,\n)" ),
+			array( array( true ), "array ({$warning}\n  0 => '',\n)" ),
+			array( array( false ), "array ({$warning}\n)" ),
+			array( array( true, ApiResult::META_BC_BOOLS => array( 0 ) ),
+				"array ({$warning}\n  0 => true,\n)" ),
+			array( array( false, ApiResult::META_BC_BOOLS => array( 0 ) ),
+				"array ({$warning}\n  0 => false,\n)" ),
 			array( array( 42 ), "array ({$warning}\n  0 => 42,\n)" ),
 			array( array( 42.5 ), "array ({$warning}\n  0 => 42.5,\n)" ),
 			array( array( 1e42 ), "array ({$warning}\n  0 => 1.0E+42,\n)" ),
@@ -29,9 +33,22 @@ class ApiFormatDbgTest extends ApiFormatTestBase {
 			array( array( array( 1 ) ), "array ({$warning}\n  0 => \n  array (\n    0 => 1,\n  ),\n)" ),
 			array( array( array( 'x' => 1 ) ), "array ({$warning}\n  0 => \n  array (\n    'x' => 1,\n  ),\n)" ),
 			array( array( array( 2 => 1 ) ), "array ({$warning}\n  0 => \n  array (\n    2 => 1,\n  ),\n)" ),
+			array( array( (object)array() ), "array ({$warning}\n  0 => \n  array (\n  ),\n)" ),
+			array( array( array( 1, ApiResult::META_TYPE => 'assoc' ) ), "array ({$warning}\n  0 => \n  array (\n    0 => 1,\n  ),\n)" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'array' ) ), "array ({$warning}\n  0 => \n  array (\n    0 => 1,\n  ),\n)" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'kvp' ) ), "array ({$warning}\n  0 => \n  array (\n    'x' => 1,\n  ),\n)" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCkvp', ApiResult::META_KVP_KEY_NAME => 'key' ) ),
+				"array ({$warning}\n  0 => \n  array (\n    0 => \n    array (\n      'key' => 'x',\n      '*' => 1,\n    ),\n  ),\n)" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCarray' ) ), "array ({$warning}\n  0 => \n  array (\n    'x' => 1,\n  ),\n)" ),
+			array( array( array( 'a', 'b', ApiResult::META_TYPE => 'BCassoc' ) ), "array ({$warning}\n  0 => \n  array (\n    0 => 'a',\n    1 => 'b',\n  ),\n)" ),
 
 			// Content
-			array( array( '*' => 'foo' ), "array ({$warning}\n  '*' => 'foo',\n)" ),
+			array( array( 'content' => 'foo', ApiResult::META_CONTENT => 'content' ),
+				"array ({$warning}\n  '*' => 'foo',\n)" ),
+
+			// BC Subelements
+			array( array( 'foo' => 'foo', ApiResult::META_BC_SUBELEMENTS => array( 'foo' ) ),
+				"array ({$warning}\n  'foo' => \n  array (\n    '*' => 'foo',\n  ),\n)" ),
 		);
 	}
 
diff --git a/tests/phpunit/includes/api/format/ApiFormatDumpTest.php b/tests/phpunit/includes/api/format/ApiFormatDumpTest.php
index 2800d2dfb6b8..c0f67f8d82e4 100644
--- a/tests/phpunit/includes/api/format/ApiFormatDumpTest.php
+++ b/tests/phpunit/includes/api/format/ApiFormatDumpTest.php
@@ -24,8 +24,12 @@ class ApiFormatDumpTest extends ApiFormatTestBase {
 		return array(
 			// Basic types
 			array( array( null ), "array(2) {{$warning}\n  [0]=>\n  NULL\n}\n" ),
-			array( array( true ), "array(2) {{$warning}\n  [0]=>\n  bool(true)\n}\n" ),
-			array( array( false ), "array(2) {{$warning}\n  [0]=>\n  bool(false)\n}\n" ),
+			array( array( true ), "array(2) {{$warning}\n  [0]=>\n  string(0) \"\"\n}\n" ),
+			array( array( false ), "array(1) {{$warning}\n}\n" ),
+			array( array( true, ApiResult::META_BC_BOOLS => array( 0 ) ),
+				"array(2) {{$warning}\n  [0]=>\n  bool(true)\n}\n" ),
+			array( array( false, ApiResult::META_BC_BOOLS => array( 0 ) ),
+				"array(2) {{$warning}\n  [0]=>\n  bool(false)\n}\n" ),
 			array( array( 42 ), "array(2) {{$warning}\n  [0]=>\n  int(42)\n}\n" ),
 			array( array( 42.5 ), "array(2) {{$warning}\n  [0]=>\n  float(42.5)\n}\n" ),
 			array( array( 1e42 ), "array(2) {{$warning}\n  [0]=>\n  float(1.0E+42)\n}\n" ),
@@ -37,9 +41,22 @@ class ApiFormatDumpTest extends ApiFormatTestBase {
 			array( array( array( 1 ) ), "array(2) {{$warning}\n  [0]=>\n  array(1) {\n    [0]=>\n    int(1)\n  }\n}\n" ),
 			array( array( array( 'x' => 1 ) ), "array(2) {{$warning}\n  [0]=>\n  array(1) {\n    [\"x\"]=>\n    int(1)\n  }\n}\n" ),
 			array( array( array( 2 => 1 ) ), "array(2) {{$warning}\n  [0]=>\n  array(1) {\n    [2]=>\n    int(1)\n  }\n}\n" ),
+			array( array( (object)array() ), "array(2) {{$warning}\n  [0]=>\n  array(0) {\n  }\n}\n" ),
+			array( array( array( 1, ApiResult::META_TYPE => 'assoc' ) ), "array(2) {{$warning}\n  [0]=>\n  array(1) {\n    [0]=>\n    int(1)\n  }\n}\n" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'array' ) ), "array(2) {{$warning}\n  [0]=>\n  array(1) {\n    [0]=>\n    int(1)\n  }\n}\n" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'kvp' ) ), "array(2) {{$warning}\n  [0]=>\n  array(1) {\n    [\"x\"]=>\n    int(1)\n  }\n}\n" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCkvp', ApiResult::META_KVP_KEY_NAME => 'key' ) ),
+				"array(2) {{$warning}\n  [0]=>\n  array(1) {\n    [0]=>\n    array(2) {\n      [\"key\"]=>\n      string(1) \"x\"\n      [\"*\"]=>\n      int(1)\n    }\n  }\n}\n" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCarray' ) ), "array(2) {{$warning}\n  [0]=>\n  array(1) {\n    [\"x\"]=>\n    int(1)\n  }\n}\n" ),
+			array( array( array( 'a', 'b', ApiResult::META_TYPE => 'BCassoc' ) ), "array(2) {{$warning}\n  [0]=>\n  array(2) {\n    [0]=>\n    string(1) \"a\"\n    [1]=>\n    string(1) \"b\"\n  }\n}\n" ),
 
 			// Content
-			array( array( '*' => 'foo' ), "array(2) {{$warning}\n  [\"*\"]=>\n  string(3) \"foo\"\n}\n" ),
+			array( array( 'content' => 'foo', ApiResult::META_CONTENT => 'content' ),
+				"array(2) {{$warning}\n  [\"*\"]=>\n  string(3) \"foo\"\n}\n" ),
+
+			// BC Subelements
+			array( array( 'foo' => 'foo', ApiResult::META_BC_SUBELEMENTS => array( 'foo' ) ),
+				"array(2) {{$warning}\n  [\"foo\"]=>\n  array(1) {\n    [\"*\"]=>\n    string(3) \"foo\"\n  }\n}\n" ),
 		);
 	}
 
diff --git a/tests/phpunit/includes/api/format/ApiFormatJsonTest.php b/tests/phpunit/includes/api/format/ApiFormatJsonTest.php
index bdf3f139478c..3dfcaf0fd7ec 100644
--- a/tests/phpunit/includes/api/format/ApiFormatJsonTest.php
+++ b/tests/phpunit/includes/api/format/ApiFormatJsonTest.php
@@ -8,34 +8,102 @@ class ApiFormatJsonTest extends ApiFormatTestBase {
 
 	protected $printerName = 'json';
 
+	private static function addFormatVersion( $format, $arr ) {
+		foreach ( $arr as &$p ) {
+			if ( !isset( $p[2] ) ) {
+				$p[2] = array( 'formatversion' => $format );
+			} else {
+				$p[2]['formatversion'] = $format;
+			}
+		}
+		return $arr;
+	}
+
 	public static function provideGeneralEncoding() {
-		return array(
-			// Basic types
-			array( array( null ), '[null]' ),
-			array( array( true ), '[true]' ),
-			array( array( false ), '[false]' ),
-			array( array( 42 ), '[42]' ),
-			array( array( 42.5 ), '[42.5]' ),
-			array( array( 1e42 ), '[1.0e+42]' ),
-			array( array( 'foo' ), '["foo"]' ),
-			array( array( 'fóo' ), '["f\u00f3o"]' ),
-			array( array( 'fóo' ), '["fóo"]', array( 'utf8' => 1 ) ),
-
-			// Arrays and objects
-			array( array( array() ), '[[]]' ),
-			array( array( array( 1 ) ), '[[1]]' ),
-			array( array( array( 'x' => 1 ) ), '[{"x":1}]' ),
-			array( array( array( 2 => 1 ) ), '[{"2":1}]' ),
-			array( array( (object)array() ), '[{}]' ),
-
-			// Content
-			array( array( '*' => 'foo' ), '{"*":"foo"}' ),
-
-			// Callbacks
-			array( array( 1 ), '/**/myCallback([1])', array( 'callback' => 'myCallback' ) ),
-
-			// Cross-domain mangling
-			array( array( '< Cross-Domain-Policy >' ), '["\u003C Cross-Domain-Policy \u003E"]' ),
+		return array_merge(
+			self::addFormatVersion( 1, array(
+				// Basic types
+				array( array( null ), '[null]' ),
+				array( array( true ), '[""]' ),
+				array( array( false ), '[]' ),
+				array( array( true, ApiResult::META_BC_BOOLS => array( 0 ) ), '[true]' ),
+				array( array( false, ApiResult::META_BC_BOOLS => array( 0 ) ), '[false]' ),
+				array( array( 42 ), '[42]' ),
+				array( array( 42.5 ), '[42.5]' ),
+				array( array( 1e42 ), '[1.0e+42]' ),
+				array( array( 'foo' ), '["foo"]' ),
+				array( array( 'fóo' ), '["f\u00f3o"]' ),
+				array( array( 'fóo' ), '["fóo"]', array( 'utf8' => 1 ) ),
+
+				// Arrays and objects
+				array( array( array() ), '[[]]' ),
+				array( array( array( 1 ) ), '[[1]]' ),
+				array( array( array( 'x' => 1 ) ), '[{"x":1}]' ),
+				array( array( array( 2 => 1 ) ), '[{"2":1}]' ),
+				array( array( (object)array() ), '[{}]' ),
+				array( array( array( 1, ApiResult::META_TYPE => 'assoc' ) ), '[{"0":1}]' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'array' ) ), '[[1]]' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'kvp' ) ), '[{"x":1}]' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCkvp', ApiResult::META_KVP_KEY_NAME => 'key' ) ),
+					'[[{"key":"x","*":1}]]' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCarray' ) ), '[{"x":1}]' ),
+				array( array( array( 'a', 'b', ApiResult::META_TYPE => 'BCassoc' ) ), '[["a","b"]]' ),
+
+				// Content
+				array( array( 'content' => 'foo', ApiResult::META_CONTENT => 'content' ),
+					'{"*":"foo"}' ),
+
+				// BC Subelements
+				array( array( 'foo' => 'foo', ApiResult::META_BC_SUBELEMENTS => array( 'foo' ) ),
+					'{"foo":{"*":"foo"}}' ),
+
+				// Callbacks
+				array( array( 1 ), '/**/myCallback([1])', array( 'callback' => 'myCallback' ) ),
+
+				// Cross-domain mangling
+				array( array( '< Cross-Domain-Policy >' ), '["\u003C Cross-Domain-Policy \u003E"]' ),
+			) ),
+			self::addFormatVersion( 2, array(
+				// Basic types
+				array( array( null ), '[null]' ),
+				array( array( true ), '[true]' ),
+				array( array( false ), '[false]' ),
+				array( array( true, ApiResult::META_BC_BOOLS => array( 0 ) ), '[true]' ),
+				array( array( false, ApiResult::META_BC_BOOLS => array( 0 ) ), '[false]' ),
+				array( array( 42 ), '[42]' ),
+				array( array( 42.5 ), '[42.5]' ),
+				array( array( 1e42 ), '[1.0e+42]' ),
+				array( array( 'foo' ), '["foo"]' ),
+				array( array( 'fóo' ), '["fóo"]' ),
+				array( array( 'fóo' ), '["f\u00f3o"]', array( 'ascii' => 1 ) ),
+
+				// Arrays and objects
+				array( array( array() ), '[[]]' ),
+				array( array( array( 'x' => 1 ) ), '[{"x":1}]' ),
+				array( array( array( 2 => 1 ) ), '[{"2":1}]' ),
+				array( array( (object)array() ), '[{}]' ),
+				array( array( array( 1, ApiResult::META_TYPE => 'assoc' ) ), '[{"0":1}]' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'array' ) ), '[[1]]' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'kvp' ) ), '[{"x":1}]' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCkvp', ApiResult::META_KVP_KEY_NAME => 'key' ) ),
+					'[{"x":1}]' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCarray' ) ), '[[1]]' ),
+				array( array( array( 'a', 'b', ApiResult::META_TYPE => 'BCassoc' ) ), '[{"0":"a","1":"b"}]' ),
+
+				// Content
+				array( array( 'content' => 'foo', ApiResult::META_CONTENT => 'content' ),
+					'{"content":"foo"}' ),
+
+				// BC Subelements
+				array( array( 'foo' => 'foo', ApiResult::META_BC_SUBELEMENTS => array( 'foo' ) ),
+					'{"foo":"foo"}' ),
+
+				// Callbacks
+				array( array( 1 ), '/**/myCallback([1])', array( 'callback' => 'myCallback' ) ),
+
+				// Cross-domain mangling
+				array( array( '< Cross-Domain-Policy >' ), '["\u003C Cross-Domain-Policy \u003E"]' ),
+			) )
 		);
 	}
 
diff --git a/tests/phpunit/includes/api/format/ApiFormatNoneTest.php b/tests/phpunit/includes/api/format/ApiFormatNoneTest.php
index 1487ad0ddb28..8f81a411e440 100644
--- a/tests/phpunit/includes/api/format/ApiFormatNoneTest.php
+++ b/tests/phpunit/includes/api/format/ApiFormatNoneTest.php
@@ -25,9 +25,19 @@ class ApiFormatNoneTest extends ApiFormatTestBase {
 			array( array( array( 1 ) ), '' ),
 			array( array( array( 'x' => 1 ) ), '' ),
 			array( array( array( 2 => 1 ) ), '' ),
+			array( array( (object)array() ), '' ),
+			array( array( array( 1, ApiResult::META_TYPE => 'assoc' ) ), '' ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'array' ) ), '' ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'kvp' ) ), '' ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCkvp', ApiResult::META_KVP_KEY_NAME => 'key' ) ), '' ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCarray' ) ), '' ),
+			array( array( array( 'a', 'b', ApiResult::META_TYPE => 'BCassoc' ) ), '' ),
 
 			// Content
 			array( array( '*' => 'foo' ), '' ),
+
+			// BC Subelements
+			array( array( 'foo' => 'foo', ApiResult::META_BC_SUBELEMENTS => array( 'foo' ) ), '' ),
 		);
 	}
 
diff --git a/tests/phpunit/includes/api/format/ApiFormatPhpTest.php b/tests/phpunit/includes/api/format/ApiFormatPhpTest.php
index 469346c8a759..0cb44e921d40 100644
--- a/tests/phpunit/includes/api/format/ApiFormatPhpTest.php
+++ b/tests/phpunit/includes/api/format/ApiFormatPhpTest.php
@@ -8,26 +8,93 @@ class ApiFormatPhpTest extends ApiFormatTestBase {
 
 	protected $printerName = 'php';
 
+	private static function addFormatVersion( $format, $arr ) {
+		foreach ( $arr as &$p ) {
+			if ( !isset( $p[2] ) ) {
+				$p[2] = array( 'formatversion' => $format );
+			} else {
+				$p[2]['formatversion'] = $format;
+			}
+		}
+		return $arr;
+	}
+
 	public static function provideGeneralEncoding() {
-		return array(
-			// Basic types
-			array( array( null ), 'a:1:{i:0;N;}' ),
-			array( array( true ), 'a:1:{i:0;b:1;}' ),
-			array( array( false ), 'a:1:{i:0;b:0;}' ),
-			array( array( 42 ), 'a:1:{i:0;i:42;}' ),
-			array( array( 42.5 ), 'a:1:{i:0;d:42.5;}' ),
-			array( array( 1e42 ), 'a:1:{i:0;d:1.0E+42;}' ),
-			array( array( 'foo' ), 'a:1:{i:0;s:3:"foo";}' ),
-			array( array( 'fóo' ), 'a:1:{i:0;s:4:"fóo";}' ),
+		return array_merge(
+			self::addFormatVersion( 1, array(
+				// Basic types
+				array( array( null ), 'a:1:{i:0;N;}' ),
+				array( array( true ), 'a:1:{i:0;s:0:"";}' ),
+				array( array( false ), 'a:0:{}' ),
+				array( array( true, ApiResult::META_BC_BOOLS => array( 0 ) ),
+					'a:1:{i:0;b:1;}' ),
+				array( array( false, ApiResult::META_BC_BOOLS => array( 0 ) ),
+					'a:1:{i:0;b:0;}' ),
+				array( array( 42 ), 'a:1:{i:0;i:42;}' ),
+				array( array( 42.5 ), 'a:1:{i:0;d:42.5;}' ),
+				array( array( 1e42 ), 'a:1:{i:0;d:1.0E+42;}' ),
+				array( array( 'foo' ), 'a:1:{i:0;s:3:"foo";}' ),
+				array( array( 'fóo' ), 'a:1:{i:0;s:4:"fóo";}' ),
+
+				// Arrays and objects
+				array( array( array() ), 'a:1:{i:0;a:0:{}}' ),
+				array( array( array( 1 ) ), 'a:1:{i:0;a:1:{i:0;i:1;}}' ),
+				array( array( array( 'x' => 1 ) ), 'a:1:{i:0;a:1:{s:1:"x";i:1;}}' ),
+				array( array( array( 2 => 1 ) ), 'a:1:{i:0;a:1:{i:2;i:1;}}' ),
+				array( array( (object)array() ), 'a:1:{i:0;a:0:{}}' ),
+				array( array( array( 1, ApiResult::META_TYPE => 'assoc' ) ), 'a:1:{i:0;a:1:{i:0;i:1;}}' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'array' ) ), 'a:1:{i:0;a:1:{i:0;i:1;}}' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'kvp' ) ), 'a:1:{i:0;a:1:{s:1:"x";i:1;}}' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCkvp', ApiResult::META_KVP_KEY_NAME => 'key' ) ),
+					'a:1:{i:0;a:1:{i:0;a:2:{s:3:"key";s:1:"x";s:1:"*";i:1;}}}' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCarray' ) ), 'a:1:{i:0;a:1:{s:1:"x";i:1;}}' ),
+				array( array( array( 'a', 'b', ApiResult::META_TYPE => 'BCassoc' ) ), 'a:1:{i:0;a:2:{i:0;s:1:"a";i:1;s:1:"b";}}' ),
+
+				// Content
+				array( array( 'content' => 'foo', ApiResult::META_CONTENT => 'content' ),
+					'a:1:{s:1:"*";s:3:"foo";}' ),
+
+				// BC Subelements
+				array( array( 'foo' => 'foo', ApiResult::META_BC_SUBELEMENTS => array( 'foo' ) ),
+					'a:1:{s:3:"foo";a:1:{s:1:"*";s:3:"foo";}}' ),
+			) ),
+			self::addFormatVersion( 2, array(
+				// Basic types
+				array( array( null ), 'a:1:{i:0;N;}' ),
+				array( array( true ), 'a:1:{i:0;b:1;}' ),
+				array( array( false ), 'a:1:{i:0;b:0;}' ),
+				array( array( true, ApiResult::META_BC_BOOLS => array( 0 ) ),
+					'a:1:{i:0;b:1;}' ),
+				array( array( false, ApiResult::META_BC_BOOLS => array( 0 ) ),
+					'a:1:{i:0;b:0;}' ),
+				array( array( 42 ), 'a:1:{i:0;i:42;}' ),
+				array( array( 42.5 ), 'a:1:{i:0;d:42.5;}' ),
+				array( array( 1e42 ), 'a:1:{i:0;d:1.0E+42;}' ),
+				array( array( 'foo' ), 'a:1:{i:0;s:3:"foo";}' ),
+				array( array( 'fóo' ), 'a:1:{i:0;s:4:"fóo";}' ),
+
+				// Arrays and objects
+				array( array( array() ), 'a:1:{i:0;a:0:{}}' ),
+				array( array( array( 1 ) ), 'a:1:{i:0;a:1:{i:0;i:1;}}' ),
+				array( array( array( 'x' => 1 ) ), 'a:1:{i:0;a:1:{s:1:"x";i:1;}}' ),
+				array( array( array( 2 => 1 ) ), 'a:1:{i:0;a:1:{i:2;i:1;}}' ),
+				array( array( (object)array() ), 'a:1:{i:0;a:0:{}}' ),
+				array( array( array( 1, ApiResult::META_TYPE => 'assoc' ) ), 'a:1:{i:0;a:1:{i:0;i:1;}}' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'array' ) ), 'a:1:{i:0;a:1:{i:0;i:1;}}' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'kvp' ) ), 'a:1:{i:0;a:1:{s:1:"x";i:1;}}' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCkvp', ApiResult::META_KVP_KEY_NAME => 'key' ) ),
+					'a:1:{i:0;a:1:{s:1:"x";i:1;}}' ),
+				array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCarray' ) ), 'a:1:{i:0;a:1:{i:0;i:1;}}' ),
+				array( array( array( 'a', 'b', ApiResult::META_TYPE => 'BCassoc' ) ), 'a:1:{i:0;a:2:{i:0;s:1:"a";i:1;s:1:"b";}}' ),
 
-			// Arrays and objects
-			array( array( array() ), 'a:1:{i:0;a:0:{}}' ),
-			array( array( array( 1 ) ), 'a:1:{i:0;a:1:{i:0;i:1;}}' ),
-			array( array( array( 'x' => 1 ) ), 'a:1:{i:0;a:1:{s:1:"x";i:1;}}' ),
-			array( array( array( 2 => 1 ) ), 'a:1:{i:0;a:1:{i:2;i:1;}}' ),
+				// Content
+				array( array( 'content' => 'foo', ApiResult::META_CONTENT => 'content' ),
+					'a:1:{s:7:"content";s:3:"foo";}' ),
 
-			// Content
-			array( array( '*' => 'foo' ), 'a:1:{s:1:"*";s:3:"foo";}' ),
+				// BC Subelements
+				array( array( 'foo' => 'foo', ApiResult::META_BC_SUBELEMENTS => array( 'foo' ) ),
+					'a:1:{s:3:"foo";s:3:"foo";}' ),
+			) )
 		);
 	}
 
diff --git a/tests/phpunit/includes/api/format/ApiFormatTxtTest.php b/tests/phpunit/includes/api/format/ApiFormatTxtTest.php
index 06e9204f5b3a..b0a2a9602a11 100644
--- a/tests/phpunit/includes/api/format/ApiFormatTxtTest.php
+++ b/tests/phpunit/includes/api/format/ApiFormatTxtTest.php
@@ -16,8 +16,12 @@ class ApiFormatTxtTest extends ApiFormatTestBase {
 		return array(
 			// Basic types
 			array( array( null ), "Array\n({$warning}\n    [0] => \n)\n" ),
-			array( array( true ), "Array\n({$warning}\n    [0] => 1\n)\n" ),
-			array( array( false ), "Array\n({$warning}\n    [0] => \n)\n" ),
+			array( array( true ), "Array\n({$warning}\n    [0] => \n)\n" ),
+			array( array( false ), "Array\n({$warning}\n)\n" ),
+			array( array( true, ApiResult::META_BC_BOOLS => array( 0 ) ),
+				"Array\n({$warning}\n    [0] => 1\n)\n" ),
+			array( array( false, ApiResult::META_BC_BOOLS => array( 0 ) ),
+				"Array\n({$warning}\n    [0] => \n)\n" ),
 			array( array( 42 ), "Array\n({$warning}\n    [0] => 42\n)\n" ),
 			array( array( 42.5 ), "Array\n({$warning}\n    [0] => 42.5\n)\n" ),
 			array( array( 1e42 ), "Array\n({$warning}\n    [0] => 1.0E+42\n)\n" ),
@@ -29,9 +33,22 @@ class ApiFormatTxtTest extends ApiFormatTestBase {
 			array( array( array( 1 ) ), "Array\n({$warning}\n    [0] => Array\n        (\n            [0] => 1\n        )\n\n)\n" ),
 			array( array( array( 'x' => 1 ) ), "Array\n({$warning}\n    [0] => Array\n        (\n            [x] => 1\n        )\n\n)\n" ),
 			array( array( array( 2 => 1 ) ), "Array\n({$warning}\n    [0] => Array\n        (\n            [2] => 1\n        )\n\n)\n" ),
+			array( array( (object)array() ), "Array\n({$warning}\n    [0] => Array\n        (\n        )\n\n)\n" ),
+			array( array( array( 1, ApiResult::META_TYPE => 'assoc' ) ), "Array\n({$warning}\n    [0] => Array\n        (\n            [0] => 1\n        )\n\n)\n" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'array' ) ), "Array\n({$warning}\n    [0] => Array\n        (\n            [0] => 1\n        )\n\n)\n" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'kvp' ) ), "Array\n({$warning}\n    [0] => Array\n        (\n            [x] => 1\n        )\n\n)\n" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCkvp', ApiResult::META_KVP_KEY_NAME => 'key' ) ),
+				"Array\n({$warning}\n    [0] => Array\n        (\n            [0] => Array\n                (\n                    [key] => x\n                    [*] => 1\n                )\n\n        )\n\n)\n" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCarray' ) ), "Array\n({$warning}\n    [0] => Array\n        (\n            [x] => 1\n        )\n\n)\n" ),
+			array( array( array( 'a', 'b', ApiResult::META_TYPE => 'BCassoc' ) ), "Array\n({$warning}\n    [0] => Array\n        (\n            [0] => a\n            [1] => b\n        )\n\n)\n" ),
 
 			// Content
-			array( array( '*' => 'foo' ), "Array\n({$warning}\n    [*] => foo\n)\n" ),
+			array( array( 'content' => 'foo', ApiResult::META_CONTENT => 'content' ),
+				"Array\n({$warning}\n    [*] => foo\n)\n" ),
+
+			// BC Subelements
+			array( array( 'foo' => 'foo', ApiResult::META_BC_SUBELEMENTS => array( 'foo' ) ),
+				"Array\n({$warning}\n    [foo] => Array\n        (\n            [*] => foo\n        )\n\n)\n" ),
 		);
 	}
 
diff --git a/tests/phpunit/includes/api/format/ApiFormatWddxTest.php b/tests/phpunit/includes/api/format/ApiFormatWddxTest.php
index 81676e0bf017..07111300aece 100644
--- a/tests/phpunit/includes/api/format/ApiFormatWddxTest.php
+++ b/tests/phpunit/includes/api/format/ApiFormatWddxTest.php
@@ -24,8 +24,12 @@ class ApiFormatWddxTest extends ApiFormatTestBase {
 		return array(
 			// Basic types
 			array( array( null ), "{$p}<var name='0'><null/></var>{$s}" ),
-			array( array( true ), "{$p}<var name='0'><boolean value='true'/></var>{$s}" ),
-			array( array( false ), "{$p}<var name='0'><boolean value='false'/></var>{$s}" ),
+			array( array( true ), "{$p}<var name='0'><string></string></var>{$s}" ),
+			array( array( false ), "{$p}{$s}" ),
+			array( array( true, ApiResult::META_BC_BOOLS => array( 0 ) ),
+				"{$p}<var name='0'><boolean value='true'/></var>{$s}" ),
+			array( array( false, ApiResult::META_BC_BOOLS => array( 0 ) ),
+				"{$p}<var name='0'><boolean value='false'/></var>{$s}" ),
 			array( array( 42 ), "{$p}<var name='0'><number>42</number></var>{$s}" ),
 			array( array( 42.5 ), "{$p}<var name='0'><number>42.5</number></var>{$s}" ),
 			array( array( 1e42 ), "{$p}<var name='0'><number>1.0E+42</number></var>{$s}" ),
@@ -37,9 +41,22 @@ class ApiFormatWddxTest extends ApiFormatTestBase {
 			array( array( array( 1 ) ), "{$p}<var name='0'><array length='1'><number>1</number></array></var>{$s}" ),
 			array( array( array( 'x' => 1 ) ), "{$p}<var name='0'><struct><var name='x'><number>1</number></var></struct></var>{$s}" ),
 			array( array( array( 2 => 1 ) ), "{$p}<var name='0'><struct><var name='2'><number>1</number></var></struct></var>{$s}" ),
+			array( array( (object)array() ), "{$p}<var name='0'><struct></struct></var>{$s}" ),
+			array( array( array( 1, ApiResult::META_TYPE => 'assoc' ) ), "{$p}<var name='0'><struct><var name='0'><number>1</number></var></struct></var>{$s}" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'array' ) ), "{$p}<var name='0'><array length='1'><number>1</number></array></var>{$s}" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'kvp' ) ), "{$p}<var name='0'><struct><var name='x'><number>1</number></var></struct></var>{$s}" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCkvp', ApiResult::META_KVP_KEY_NAME => 'key' ) ),
+				"{$p}<var name='0'><array length='1'><struct><var name='key'><string>x</string></var><var name='*'><number>1</number></var></struct></array></var>{$s}" ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCarray' ) ), "{$p}<var name='0'><struct><var name='x'><number>1</number></var></struct></var>{$s}" ),
+			array( array( array( 'a', 'b', ApiResult::META_TYPE => 'BCassoc' ) ), "{$p}<var name='0'><array length='2'><string>a</string><string>b</string></array></var>{$s}" ),
 
 			// Content
-			array( array( '*' => 'foo' ), "{$p}<var name='*'><string>foo</string></var>{$s}" ),
+			array( array( 'content' => 'foo', ApiResult::META_CONTENT => 'content' ),
+				"{$p}<var name='*'><string>foo</string></var>{$s}" ),
+
+			// BC Subelements
+			array( array( 'foo' => 'foo', ApiResult::META_BC_SUBELEMENTS => array( 'foo' ) ),
+				"{$p}<var name='foo'><struct><var name='*'><string>foo</string></var></struct></var>{$s}" ),
 		);
 	}
 
diff --git a/tests/phpunit/includes/api/format/ApiFormatXmlTest.php b/tests/phpunit/includes/api/format/ApiFormatXmlTest.php
index afb47e7134ef..0c31b95770a4 100644
--- a/tests/phpunit/includes/api/format/ApiFormatXmlTest.php
+++ b/tests/phpunit/includes/api/format/ApiFormatXmlTest.php
@@ -9,8 +9,8 @@ class ApiFormatXmlTest extends ApiFormatTestBase {
 
 	protected $printerName = 'xml';
 
-	protected function setUp() {
-		parent::setUp();
+	public static function setUpBeforeClass() {
+		parent::setUpBeforeClass();
 		$page = WikiPage::factory( Title::newFromText( 'MediaWiki:ApiFormatXmlTest.xsl' ) );
 		$page->doEditContent( new WikitextContent(
 			'<?xml version="1.0"?><xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" />'
@@ -22,29 +22,79 @@ class ApiFormatXmlTest extends ApiFormatTestBase {
 	}
 
 	public static function provideGeneralEncoding() {
-		$tests = array(
+		return array(
 			// Basic types
-			array( array( null ), '<?xml version="1.0"?><api><x /></api>' ),
-			array( array( true, 'a' => true ), '<?xml version="1.0"?><api a=""><x>1</x></api>' ),
-			array( array( false, 'a' => false ), '<?xml version="1.0"?><api><x></x></api>' ),
-			array( array( 42, 'a' => 42 ), '<?xml version="1.0"?><api a="42"><x>42</x></api>' ),
-			array( array( 42.5, 'a' => 42.5 ), '<?xml version="1.0"?><api a="42.5"><x>42.5</x></api>' ),
-			array( array( 1e42, 'a' => 1e42 ), '<?xml version="1.0"?><api a="1.0E+42"><x>1.0E+42</x></api>' ),
-			array( array( 'foo', 'a' => 'foo' ), '<?xml version="1.0"?><api a="foo"><x>foo</x></api>' ),
-			array( array( 'fóo', 'a' => 'fóo' ), '<?xml version="1.0"?><api a="fóo"><x>fóo</x></api>' ),
+			array( array( null, 'a' => null ), '<?xml version="1.0"?><api><_v _idx="0" /></api>' ),
+			array( array( true, 'a' => true ), '<?xml version="1.0"?><api a=""><_v _idx="0">true</_v></api>' ),
+			array( array( false, 'a' => false ), '<?xml version="1.0"?><api><_v _idx="0">false</_v></api>' ),
+			array( array( true, 'a' => true, ApiResult::META_BC_BOOLS => array( 0, 'a' ) ),
+				'<?xml version="1.0"?><api a=""><_v _idx="0">1</_v></api>' ),
+			array( array( false, 'a' => false, ApiResult::META_BC_BOOLS => array( 0, 'a' ) ),
+				'<?xml version="1.0"?><api><_v _idx="0"></_v></api>' ),
+			array( array( 42, 'a' => 42 ), '<?xml version="1.0"?><api a="42"><_v _idx="0">42</_v></api>' ),
+			array( array( 42.5, 'a' => 42.5 ), '<?xml version="1.0"?><api a="42.5"><_v _idx="0">42.5</_v></api>' ),
+			array( array( 1e42, 'a' => 1e42 ), '<?xml version="1.0"?><api a="1.0E+42"><_v _idx="0">1.0E+42</_v></api>' ),
+			array( array( 'foo', 'a' => 'foo' ), '<?xml version="1.0"?><api a="foo"><_v _idx="0">foo</_v></api>' ),
+			array( array( 'fóo', 'a' => 'fóo' ), '<?xml version="1.0"?><api a="fóo"><_v _idx="0">fóo</_v></api>' ),
 
 			// Arrays and objects
-			array( array( array() ), '<?xml version="1.0"?><api><x /></api>' ),
-			array( array( array( 'x' => 1 ) ), '<?xml version="1.0"?><api><x x="1" /></api>' ),
-			array( array( array( 2 => 1, '_element' => 'x' ) ), '<?xml version="1.0"?><api><x><x>1</x></x></api>' ),
+			array( array( array() ), '<?xml version="1.0"?><api><_v /></api>' ),
+			array( array( array( 'x' => 1 ) ), '<?xml version="1.0"?><api><_v x="1" /></api>' ),
+			array( array( array( 2 => 1 ) ), '<?xml version="1.0"?><api><_v><_v _idx="2">1</_v></_v></api>' ),
+			array( array( (object)array() ), '<?xml version="1.0"?><api><_v /></api>' ),
+			array( array( array( 1, ApiResult::META_TYPE => 'assoc' ) ), '<?xml version="1.0"?><api><_v><_v _idx="0">1</_v></_v></api>' ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'array' ) ), '<?xml version="1.0"?><api><_v><_v>1</_v></_v></api>' ),
+			array( array( array( 'x' => 1, 'y' => array( 'z' => 1 ), ApiResult::META_TYPE => 'kvp' ) ),
+				'<?xml version="1.0"?><api><_v><_v _name="x" xml:space="preserve">1</_v><_v _name="y"><z xml:space="preserve">1</z></_v></_v></api>' ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'kvp', ApiResult::META_INDEXED_TAG_NAME => 'i', ApiResult::META_KVP_KEY_NAME => 'key' ) ),
+				'<?xml version="1.0"?><api><_v><i key="x" xml:space="preserve">1</i></_v></api>' ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCkvp', ApiResult::META_KVP_KEY_NAME => 'key' ) ),
+				'<?xml version="1.0"?><api><_v><_v key="x" xml:space="preserve">1</_v></_v></api>' ),
+			array( array( array( 'x' => 1, ApiResult::META_TYPE => 'BCarray' ) ), '<?xml version="1.0"?><api><_v x="1" /></api>' ),
+			array( array( array( 'a', 'b', ApiResult::META_TYPE => 'BCassoc' ) ), '<?xml version="1.0"?><api><_v><_v _idx="0">a</_v><_v _idx="1">b</_v></_v></api>' ),
 
 			// Content
-			array( array( '*' => 'foo' ), '<?xml version="1.0"?><api xml:space="preserve">foo</api>' ),
+			array( array( 'content' => 'foo', ApiResult::META_CONTENT => 'content' ),
+				'<?xml version="1.0"?><api xml:space="preserve">foo</api>' ),
+
+			// Specified element name
+			array( array( 'foo', 'bar', ApiResult::META_INDEXED_TAG_NAME => 'itn' ),
+				'<?xml version="1.0"?><api><itn>foo</itn><itn>bar</itn></api>' ),
 
 			// Subelements
 			array( array( 'a' => 1, 's' => 1, '_subelements' => array( 's' ) ),
 				'<?xml version="1.0"?><api a="1"><s xml:space="preserve">1</s></api>' ),
 
+			// Content and subelement
+			array( array( 'a' => 1, 'content' => 'foo', ApiResult::META_CONTENT => 'content' ),
+				'<?xml version="1.0"?><api a="1" xml:space="preserve">foo</api>' ),
+			array( array( 's' => array(), 'content' => 'foo', ApiResult::META_CONTENT => 'content' ),
+				'<?xml version="1.0"?><api><s /><content xml:space="preserve">foo</content></api>' ),
+			array(
+				array(
+					's' => 1,
+					'content' => 'foo',
+					ApiResult::META_CONTENT => 'content',
+					ApiResult::META_SUBELEMENTS => array( 's' )
+				),
+				'<?xml version="1.0"?><api><s xml:space="preserve">1</s><content xml:space="preserve">foo</content></api>'
+			),
+
+			// BC Subelements
+			array( array( 'foo' => 'foo', ApiResult::META_BC_SUBELEMENTS => array( 'foo' ) ),
+				'<?xml version="1.0"?><api><foo xml:space="preserve">foo</foo></api>' ),
+
+			// Name mangling
+			array( array( 'foo.bar' => 1 ), '<?xml version="1.0"?><api foo.bar="1" />' ),
+			array( array( '' => 1 ), '<?xml version="1.0"?><api _="1" />' ),
+			array( array( 'foo bar' => 1 ), '<?xml version="1.0"?><api _foo.20.bar="1" />' ),
+			array( array( 'foo:bar' => 1 ), '<?xml version="1.0"?><api _foo.3A.bar="1" />' ),
+			array( array( 'foo%.bar' => 1 ), '<?xml version="1.0"?><api _foo.25..2E.bar="1" />' ),
+			array( array( '4foo' => 1, 'foo4' => 1 ), '<?xml version="1.0"?><api _4foo="1" foo4="1" />' ),
+			array( array( "foo\xe3\x80\x80bar" => 1 ), '<?xml version="1.0"?><api _foo.3000.bar="1" />' ),
+			array( array( 'foo:bar' => 1, ApiResult::META_PRESERVE_KEYS => array( 'foo:bar' ) ),
+				'<?xml version="1.0"?><api foo:bar="1" />' ),
+
 			// includenamespace param
 			array( array( 'x' => 'foo' ), '<?xml version="1.0"?><api x="foo" xmlns="http://www.mediawiki.org/xml/api/" />',
 				array( 'includexmlnamespace' => 1 ) ),
@@ -62,40 +112,6 @@ class ApiFormatXmlTest extends ApiFormatTestBase {
 					'" type="text/xsl" ?><api />',
 				array( 'xslt' => 'MediaWiki:ApiFormatXmlTest.xsl' ) ),
 		);
-
-		// Add in the needed "_element" for all indexed arrays
-		$ret = array();
-		foreach ( $tests as $v ) {
-			$v[0] += array( '_element' => 'x' );
-			$ret[] = $v;
-		}
-		return $ret;
-	}
-
-	/**
-	 * @dataProvider provideXmlFail
-	 */
-	public function testXmlFail( array $data, $expect, array $params = array() ) {
-		try {
-			echo $this->encodeData( $params, $data ) . "\n";
-			$this->fail( "Expected exception not thrown" );
-		} catch ( MWException $ex ) {
-			$this->assertSame( $expect, $ex->getMessage(), 'Expected exception' );
-		}
-	}
-
-	public static function provideXmlFail() {
-		return array(
-			// Array without _element
-			array( array( 1 ), 'Internal error in ApiFormatXml::recXmlPrint: (api, ...) has integer keys without _element value. Use ApiResult::setIndexedTagName().' ),
-			// Content and subelement
-			array( array( 1, 's' => array(), '*' => 2, '_element' => 'x' ), 'Internal error in ApiFormatXml::recXmlPrint: (api, ...) has content and subelements' ),
-			array( array( 1, 's' => 1, '*' => 2, '_element' => 'x', '_subelements' => array( 's' ) ), 'Internal error in ApiFormatXml::recXmlPrint: (api, ...) has content and subelements' ),
-			// These should fail but don't because of a long-standing bug (see T57371#639713)
-			//array( array( 1, '*' => 2, '_element' => 'x' ), 'Internal error in ApiFormatXml::recXmlPrint: (api, ...) has content and subelements' ),
-			//array( array( 's' => array(), '*' => 2 ), 'Internal error in ApiFormatXml::recXmlPrint: (api, ...) has content and subelements' ),
-			//array( array( 's' => 1, '*' => 2, '_subelements' => array( 's' ) ), 'Internal error in ApiFormatXml::recXmlPrint: (api, ...) has content and subelements' ),
-		);
 	}
 
 }