Add test for copy block code

Author: GuillaumeGomez

src/librustdoc/html/highlight/tests.rs

@@ -55,6 +55,7 @@ use self::whatever;
 let x = super::b::foo;
 let y = Self::whatever;";
 
+        let src = once(Line::Shown(Cow::Borrowed(src)));
         let mut html = Buffer::new();
         write_code(&mut html, src, Edition::Edition2018, None);
         expect_file!["fixtures/highlight.html"].assert_eq(&html.into_inner());

src/test/rustdoc-gui/code_block_lines.goml

@@ -0,0 +1,14 @@
+goto: file://|DOC_PATH|/lib2/trait.Trait.html
+// We set the parameter to display line numbers on code blocks.
+local-storage: {"rustdoc-line-numbers": "true"}
+// We reload the page so they're displayed.
+reload:
+wait-for: ".line-number"
+assert: ".top-doc .line-number"
+assert-text: (".top-doc .line-number", "1\n2\n3\n4")
+// We check that the hidden content is present
+assert: ".top-doc .rust-example-rendered span.hidden"
+assert-text: (".top-doc .rust-example-rendered span.hidden", "fn main() {\n")
+assert-text: (".methods .line-number", "1\n2\n3\n4\n5\n6\n7")
+// We unset the parameter to be sure it won't affect other tests.
+local-storage: {"rustdoc-line-numbers": ""}

src/test/rustdoc-gui/src/lib2/lib.rs

@@ -25,10 +25,30 @@ impl Foo {
     pub fn a_method(&self) {}
 }
 
+// This is used to ensure the line numbers are correctly set.
+/// ```
+/// # fn main() {
+/// let x = 12;
+/// let y = 13;
+/// # let z = 14;
+///
+/// println!("hello");
+/// # }
+/// ```
 pub trait Trait {
     type X;
     const Y: u32;
 
+    // This is used to ensure the line numbers are correctly set.
+    /// ```
+    /// fn main() {
+    /// let x = 12;
+    /// let y = 13;
+    /// let z = 14;
+    ///
+    /// println!("hello");
+    /// }
+    /// ```
     fn foo() {}
 }