Rollup merge of #106888 - GuillaumeGomez:tidy-gui-test, r=notriddle

Add tidy check to ensure that rustdoc GUI tests start with a small description

The first commit comes from https://github.com/rust-lang/rust/pull/106865 to prevent CI to fail.

This PR adds a tidy check to enforce having a small description at the top of the GUI test. Although the format is made to be as easy as possible to read, it's not always obvious what a test is actually checking. I think enforcing this will make it easier for us to come back on these tests if needed.

r? `@notriddle`

4 files changed, 37 insertions, 0 deletions

diff --git a/src/tools/tidy/src/lib.rs b/src/tools/tidy/src/lib.rs
index 40375f1306d..97e56720b98 100644
--- a/src/tools/tidy/src/lib.rs
+++ b/src/tools/tidy/src/lib.rs
@@ -62,6 +62,7 @@ pub mod features;
 pub mod mir_opt_tests;
 pub mod pal;
 pub mod primitive_docs;
+pub mod rustdoc_gui_tests;
 pub mod style;
 pub mod target_specific_tests;
 pub mod tests_placement;
diff --git a/src/tools/tidy/src/main.rs b/src/tools/tidy/src/main.rs
index ea2886a3c2f..0b9a1b37e94 100644
--- a/src/tools/tidy/src/main.rs
+++ b/src/tools/tidy/src/main.rs
@@ -80,6 +80,7 @@ fn main() {
         check!(debug_artifacts, &tests_path);
         check!(ui_tests, &tests_path);
         check!(mir_opt_tests, &tests_path, bless);
+        check!(rustdoc_gui_tests, &tests_path);
 
         // Checks that only make sense for the compiler.
         check!(error_codes, &root_path, &[&compiler_path, &librustdoc_path], verbose);
diff --git a/src/tools/tidy/src/rustdoc_gui_tests.rs b/src/tools/tidy/src/rustdoc_gui_tests.rs
new file mode 100644
index 00000000000..feb513df34b
--- /dev/null
+++ b/src/tools/tidy/src/rustdoc_gui_tests.rs
@@ -0,0 +1,33 @@
+//! Tidy check to ensure that rustdoc GUI tests start with a small description.
+
+use std::path::Path;
+
+pub fn check(path: &Path, bad: &mut bool) {
+    crate::walk::walk(
+        &path.join("rustdoc-gui"),
+        &mut |p| {
+            // If there is no extension, it's very likely a folder and we want to go into it.
+            p.extension().map(|e| e != "goml").unwrap_or(false)
+        },
+        &mut |entry, content| {
+            for line in content.lines() {
+                if !line.starts_with("// ") {
+                    tidy_error!(
+                        bad,
+                        "{}: rustdoc-gui tests must start with a small description",
+                        entry.path().display(),
+                    );
+                    return;
+                } else if line.starts_with("// ") {
+                    let parts = line[2..].trim();
+                    // We ignore tidy comments.
+                    if parts.starts_with("// tidy-") {
+                        continue;
+                    }
+                    // All good!
+                    return;
+                }
+            }
+        },
+    );
+}
diff --git a/tests/rustdoc-gui/basic-code.goml b/tests/rustdoc-gui/basic-code.goml
index 108cf8abcb5..971c2f9480e 100644
--- a/tests/rustdoc-gui/basic-code.goml
+++ b/tests/rustdoc-gui/basic-code.goml
@@ -1,3 +1,5 @@
+// Small test to ensure the "src-line-numbers" element is only present once on
+// the page.
 goto: "file://" + |DOC_PATH| + "/test_docs/index.html"
 click: ".srclink"
 wait-for: ".src-line-numbers"