Add test to ensure that the element pointed to by the URL hash is "expanded"

Author: GuillaumeGomez

src/test/rustdoc-gui/hash-item-expansion.goml

@@ -0,0 +1,18 @@
+// This test ensures that the element corresponding to the hash is displayed.
+goto: file://|DOC_PATH|/struct.Foo.html#method.borrow
+// In the blanket implementations list, "Borrow" is the second one, hence the ":nth(2)".
+assert: ("#blanket-implementations-list > details:nth-child(2)", "open", "")
+// Please note the "\" below is needed because otherwise ".borrow" would be interpreted as
+// a class selector.
+assert: ("#method\.borrow", {"display": "flex"})
+// We first check that the impl block is open by default.
+assert: ("#implementations + details", "open", "")
+// We collapse it.
+click: "#implementations + details > summary"
+// We check that it was collapsed as expected.
+assert-false: ("#implementations + details", "open", "")
+// To ensure that we will click on the currently hidden method.
+assert: (".sidebar-links > a", "must_use")
+click: ".sidebar-links > a"
+// We check that the impl block was opened as expected so that we can see the method.
+assert: ("#implementations + details", "open", "")