Add GUI test for code wrapping

tests/rustdoc-gui/source-code-wrapping.goml

@@ -0,0 +1,44 @@
+// Checks that the interactions with the source code pages are working as expected.
+go-to: "file://" + |DOC_PATH| + "/src/test_docs/lib.rs.html"
+show-text: true
+
+define-function: (
+    "click-code-wrapping",
+    [expected],
+    block {
+        click: "#wrap-source-code"
+        wait-for-local-storage: {"rustdoc-wrap-source-code": |expected|}
+    },
+)
+
+store-size: (".rust code", {"width": width, "height": height})
+click: "#settings-menu"
+wait-for: "#settings"
+call-function: ("click-code-wrapping", {"expected": "true"})
+store-size: (".rust code", {"width": new_width, "height": new_height})
+// The width should now be smaller than the window's and the height
+// should have increased.
+assert: |width| > |new_width| && |height| < |new_height|
+
+// Switching back to the original setting.
+call-function: ("click-code-wrapping", {"expected": "false"})
+assert-size: (".rust code", {"width": |width|, "height": |height|})
+
+// Now let's check in docs code examples.
+go-to: "file://" + |DOC_PATH| + "/test_docs/trait_bounds/index.html"
+click: "#settings-menu"
+wait-for: "#settings"
+
+store-size: (".example-wrap .rust code", {"width": rust_width, "height": rust_height})
+store-size: (".example-wrap .language-text code", {"width": txt_width, "height": txt_height})
+call-function: ("click-code-wrapping", {"expected": "true"})
+
+store-size: (".example-wrap .rust code", {"width": new_rust_width, "height": new_rust_height})
+store-size: (".example-wrap .language-text code", {"width": new_txt_width, "height": new_txt_height})
+
+assert: |rust_width| > |new_rust_width| && |rust_height| < |new_rust_height|
+assert: |txt_width| > |new_txt_width| && |txt_height| < |new_txt_height|
+
+call-function: ("click-code-wrapping", {"expected": "false"})
+assert-size: (".example-wrap .rust code", {"width": |rust_width|, "height": |rust_height|})
+assert-size: (".example-wrap .language-text code", {"width": |txt_width|, "height": |txt_height|})

tests/rustdoc-gui/src/test_docs/lib.rs

@@ -615,6 +615,15 @@ pub enum Enum {
     }
 }
 
+/// ```
+/// fn super_long_function_name_because_i_need_to_hit_the_limit_and_break_beyond_it() {
+/// }
+/// ```
+///
+/// ```text
+/// fn super_long_function_name_because_i_need_to_hit_the_limit_and_break_beyond_it_v2() {
+/// }
+/// ```
 pub mod trait_bounds {
     pub trait OneBound: Sized {}
     pub trait TwoBounds: Sized + Copy {}