language: fix mw.language.convertGrammar with word-specific casing rules

Why:

- mw.language.convertGrammar is responsible for implementing grammatical
  transformations for inflected languages, similar to its backend
  counterpart Language::convertGrammar.
- The default implementation may be overridden by language-specific
  implementations loaded dynamically based on the user language.
- Both the default implementation and all language-specific
  implementations suffer from a bug where requesting a case
  transformation for which word-specific casing rules are defined will
  return "undefined" if the case transformation was requested for a word
  for which no word-specific casing rule exists.
- There are QUnit tests for the logic, but they only run if the user
  language matches the language being tested. This means they never run
  in CI and cannot even be run locally, since Special:JavaScriptTest has
  been forcing the user language to "qqx" for more than five years.

What:

- Place language-specific convertGrammar overrides into a new
  convertGrammarMapping property keyed by language code to allow
  loading more than one simultaneously.
- Introduce and use a new 'mediawiki.language.grammar.testdata'
  test-only RL module that loads every language-specific convertGrammar
  override.
- Introduce and use a new 'mediawiki.language.testdata' test-only RL
  module that loads language-specific rules for languages that we have
  QUnit tests for. Since this only covers less than two dozen languages,
  there'd be no value in loading this data for all 300+ languages
  supported by MediaWiki.
- Update QUnit tests for convertGrammar to override the user language
  and language rules before each case.
- Ensure word-specific casing rules always take precedence over
  language-specific convertGrammar implementations to avoid repeated
  boilerplate in language-specific code.
- Don't attempt to use word-specific casing rules for words that do not
  have one.
- As we're here, add matching PHPUnit tests for Language* subclasses
  that had preexisting QUnit tests but no PHPUnit tests.

Bug: T388370
Change-Id: I3f2432f5f801c2a7e4390c2ff2038363a36e2ed9

1 files changed, 40 insertions, 0 deletions

diff --git a/tests/phpunit/includes/languages/LanguageFiTest.php b/tests/phpunit/includes/languages/LanguageFiTest.php
new file mode 100644
index 000000000000..fb9efd76e493
--- /dev/null
+++ b/tests/phpunit/includes/languages/LanguageFiTest.php
@@ -0,0 +1,40 @@
+<?php
+declare( strict_types=1 );
+
+/**
+ * @group Language
+ * @covers LanguageFi
+ */
+class LanguageFiTest extends LanguageClassesTestCase {
+	/**
+	 * @dataProvider provideConvertGrammar
+	 */
+	public function testConvertGrammar( string $word, string $case, string $expected ): void {
+		$this->assertSame( $expected, $this->getLang()->convertGrammar( $word, $case ) );
+	}
+
+	public static function provideConvertGrammar(): iterable {
+		$wordCaseMappings = [
+			'talo' => [
+				'genitive' => 'talon',
+				'elative' => 'talosta',
+				'partitive' => 'taloa',
+				'illative' => 'taloon',
+				'inessive' => 'talossa',
+			],
+			'pastöroitu' => [
+				'partitive' => 'pastöroitua',
+			],
+			'Wikipedia' => [
+				'elative' => 'Wikipediasta',
+				'partitive' => 'Wikipediaa',
+			],
+		];
+
+		foreach ( $wordCaseMappings as $word => $caseMappings ) {
+			foreach ( $caseMappings as $case => $expected ) {
+				yield "$word $case" => [ (string)$word, $case, $expected ];
+			}
+		}
+	}
+}