Add CI step for checking redundant test patches (#7126)

.github/workflows/ci.yaml

@@ -456,10 +456,17 @@ jobs:
         run: python -I scripts/whats_left.py --no-default-features --features "$(sed -e 's/--[^ ]*//g' <<< "${{ env.CARGO_ARGS }}" | tr -d '[:space:]'),threading" # no jit on macOS for now
 
   lint:
-    name: Check Rust code with clippy
+    name: Lint Rust & Python code
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v6.0.2
+      - uses: actions/setup-python@v6.2.0
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+
+      - name: Check for redundant test patches
+        run: python scripts/check_redundant_patches.py
+
       - uses: dtolnay/rust-toolchain@stable
         with:
           components: clippy

scripts/check_redundant_patches.py

@@ -0,0 +1,52 @@
+#!/usr/bin/env python
+import ast
+import pathlib
+import sys
+
+ROOT = pathlib.Path(__file__).parents[1]
+TEST_DIR = ROOT / "Lib" / "test"
+
+
+def main():
+    exit_status = 0
+    for file in TEST_DIR.rglob("**/*.py"):
+        try:
+            contents = file.read_text(encoding="utf-8")
+        except UnicodeDecodeError:
+            continue
+
+        try:
+            tree = ast.parse(contents)
+        except SyntaxError:
+            continue
+
+        for node in ast.walk(tree):
+            if not isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef)):
+                continue
+
+            name = node.name
+            if not name.startswith("test"):
+                continue
+
+            if node.decorator_list:
+                continue
+
+            func_code = ast.unparse(node.body)
+            if func_code in (
+                f"await super().{name}()",
+                f"return await super().{name}()",
+                f"return super().{name}()",
+                f"super().{name}()",
+            ):
+                exit_status += 1
+                rel = file.relative_to(ROOT)
+                lineno = node.lineno
+                print(
+                    f"{rel}:{name}:{lineno} is a test patch that can be safely removed",
+                    file=sys.stderr,
+                )
+    return exit_status
+
+
+if __name__ == "__main__":
+    exit(main())