Auto merge of #14271 - linclark:13548-bg-parsing-test, r=canaltinova

Add tests for background shorthand parsing

<!-- Please describe your changes on the following line: -->
This PR adds tests for parsing the background shorthand.

Copies & adapts the tests from mask.rs (minus  the mode test), and adds a test for comma separated declarations.

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #13548 (github issue number if applicable).

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- [ ] There are tests for these changes OR
- [X] These changes do not require tests because they are tests

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2 files changed, 126 insertions, 0 deletions

diff --git a/tests/unit/style/parsing/background.rs b/tests/unit/style/parsing/background.rs
new file mode 100644
index 00000000000..278291d70e7
--- /dev/null
+++ b/tests/unit/style/parsing/background.rs
@@ -0,0 +1,125 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use cssparser::Parser;
+use media_queries::CSSErrorReporterTest;
+use servo_url::ServoUrl;
+use style::parser::ParserContext;
+use style::properties::longhands::{background_attachment, background_clip, background_color, background_image};
+use style::properties::longhands::{background_origin, background_position, background_repeat, background_size};
+use style::properties::shorthands::background;
+use style::stylesheets::Origin;
+
+#[test]
+fn background_shorthand_should_parse_all_available_properties_when_specified() {
+    let url = ServoUrl::parse("http://localhost").unwrap();
+    let context = ParserContext::new(Origin::Author, &url, Box::new(CSSErrorReporterTest));
+    let mut parser = Parser::new("url(\"http://servo/test.png\") top center / 200px 200px repeat-x fixed padding-box \
+        content-box red");
+    let result = background::parse_value(&context, &mut parser).unwrap();
+
+    assert_eq!(result.background_image.unwrap(), parse_longhand!(background_image, "url(\"http://servo/test.png\")"));
+    assert_eq!(result.background_position.unwrap(), parse_longhand!(background_position, "top center"));
+    assert_eq!(result.background_size.unwrap(), parse_longhand!(background_size, "200px 200px"));
+    assert_eq!(result.background_repeat.unwrap(), parse_longhand!(background_repeat, "repeat-x"));
+    assert_eq!(result.background_attachment.unwrap(), parse_longhand!(background_attachment, "fixed"));
+    assert_eq!(result.background_origin.unwrap(), parse_longhand!(background_origin, "padding-box"));
+    assert_eq!(result.background_clip.unwrap(), parse_longhand!(background_clip, "content-box"));
+    assert_eq!(result.background_color.unwrap(), parse_longhand!(background_color, "red"));
+}
+
+#[test]
+fn background_shorthand_should_parse_when_some_fields_set() {
+    let url = ServoUrl::parse("http://localhost").unwrap();
+    let context = ParserContext::new(Origin::Author, &url, Box::new(CSSErrorReporterTest));
+    let mut parser = Parser::new("14px 40px repeat-y");
+    let result = background::parse_value(&context, &mut parser).unwrap();
+
+    assert_eq!(result.background_position.unwrap(), parse_longhand!(background_position, "14px 40px"));
+    assert_eq!(result.background_repeat.unwrap(), parse_longhand!(background_repeat, "repeat-y"));
+
+    let mut parser = Parser::new("url(\"http://servo/test.png\") repeat blue");
+    let result = background::parse_value(&context, &mut parser).unwrap();
+
+    assert_eq!(result.background_image.unwrap(), parse_longhand!(background_image, "url(\"http://servo/test.png\")"));
+    assert_eq!(result.background_repeat.unwrap(), parse_longhand!(background_repeat, "repeat"));
+    assert_eq!(result.background_color.unwrap(), parse_longhand!(background_color, "blue"));
+
+    let mut parser = Parser::new("padding-box");
+    let result = background::parse_value(&context, &mut parser).unwrap();
+
+    assert_eq!(result.background_origin.unwrap(), parse_longhand!(background_origin, "padding-box"));
+    assert_eq!(result.background_clip.unwrap(), parse_longhand!(background_clip, "padding-box"));
+
+    let mut parser = Parser::new("url(\"http://servo/test.png\")");
+    let result = background::parse_value(&context, &mut parser).unwrap();
+
+    assert_eq!(result.background_image.unwrap(), parse_longhand!(background_image, "url(\"http://servo/test.png\")"));
+}
+
+#[test]
+fn background_shorthand_should_parse_comma_separated_declarations() {
+    let url = ServoUrl::parse("http://localhost").unwrap();
+    let context = ParserContext::new(Origin::Author, &url, Box::new(CSSErrorReporterTest));
+    let mut parser = Parser::new("url(\"http://servo/test.png\") top left no-repeat, url(\"http://servo/test.png\") \
+        center / 100% 100% no-repeat, white");
+    let result = background::parse_value(&context, &mut parser).unwrap();
+
+    assert_eq!(result.background_image.unwrap(), parse_longhand!(background_image, "url(\"http://servo/test.png\"), \
+        url(\"http://servo/test.png\"), none"));
+    assert_eq!(result.background_position.unwrap(), parse_longhand!(background_position, "left top, center center, \
+        0% 0%"));
+    assert_eq!(result.background_repeat.unwrap(), parse_longhand!(background_repeat, "no-repeat, no-repeat, repeat"));
+    assert_eq!(result.background_clip.unwrap(), parse_longhand!(background_clip, "border-box, border-box, border-box"));
+    assert_eq!(result.background_origin.unwrap(), parse_longhand!(background_origin, "padding-box, padding-box, \
+        padding-box"));
+    assert_eq!(result.background_size.unwrap(), parse_longhand!(background_size, "auto auto, 100% 100%, auto auto"));
+    assert_eq!(result.background_attachment.unwrap(), parse_longhand!(background_attachment, "scroll, scroll, scroll"));
+    assert_eq!(result.background_color.unwrap(), parse_longhand!(background_color, "white"));
+}
+
+#[test]
+fn background_shorthand_should_parse_position_and_size_correctly() {
+    let url = ServoUrl::parse("http://localhost").unwrap();
+    let context = ParserContext::new(Origin::Author, &url, Box::new(CSSErrorReporterTest));
+    let mut parser = Parser::new("7px 4px");
+    let result = background::parse_value(&context, &mut parser).unwrap();
+
+    assert_eq!(result.background_position.unwrap(), parse_longhand!(background_position, "7px 4px"));
+
+    let mut parser = Parser::new("7px 4px / 30px 20px");
+    let result = background::parse_value(&context, &mut parser).unwrap();
+
+    assert_eq!(result.background_position.unwrap(), parse_longhand!(background_position, "7px 4px"));
+    assert_eq!(result.background_size.unwrap(), parse_longhand!(background_size, "30px 20px"));
+
+    let mut parser = Parser::new("/ 30px 20px");
+    assert!(background::parse_value(&context, &mut parser).is_err());
+
+    let mut parser = Parser::new("repeat-x / 30px 20px");
+    assert!(background::parse_value(&context, &mut parser).is_err());
+}
+
+#[test]
+fn background_shorthand_should_parse_origin_and_clip_correctly() {
+    let url = ServoUrl::parse("http://localhost").unwrap();
+    let context = ParserContext::new(Origin::Author, &url, Box::new(CSSErrorReporterTest));
+    let mut parser = Parser::new("padding-box content-box");
+    let result = background::parse_value(&context, &mut parser).unwrap();
+
+    assert_eq!(result.background_origin.unwrap(), parse_longhand!(background_origin, "padding-box"));
+    assert_eq!(result.background_clip.unwrap(), parse_longhand!(background_clip, "content-box"));
+
+    let mut parser = Parser::new("padding-box padding-box");
+    let result = background::parse_value(&context, &mut parser).unwrap();
+
+    assert_eq!(result.background_origin.unwrap(), parse_longhand!(background_origin, "padding-box"));
+    assert_eq!(result.background_clip.unwrap(), parse_longhand!(background_clip, "padding-box"));
+
+    let mut parser = Parser::new("padding-box");
+    let result = background::parse_value(&context, &mut parser).unwrap();
+
+    assert_eq!(result.background_origin.unwrap(), parse_longhand!(background_origin, "padding-box"));
+    assert_eq!(result.background_clip.unwrap(), parse_longhand!(background_clip, "padding-box"));
+}
diff --git a/tests/unit/style/parsing/mod.rs b/tests/unit/style/parsing/mod.rs
index 5f7735e5df2..8e12018a7a3 100644
--- a/tests/unit/style/parsing/mod.rs
+++ b/tests/unit/style/parsing/mod.rs
@@ -61,6 +61,7 @@ macro_rules! parse_longhand {
     }};
 }
 
+mod background;
 mod basic_shape;
 mod border;
 mod font;