Split checker and codemod tests into individual test cases via metafunc

Few pathlib cleanups

tests/test_torchfix.py

@@ -16,68 +16,76 @@
 LOGGER = logging.getLogger(__name__)
 
 
+def pytest_generate_tests(metafunc):
+    # Dynamically generate test cases from paths
+    if "checker_source_path" in metafunc.fixturenames:
+        files = list(FIXTURES_PATH.glob("**/checker/*.py"))
+        metafunc.parametrize(
+            "checker_source_path", files, ids=[file_name.stem for file_name in files]
+        )
+    if "codemod_source_path" in metafunc.fixturenames:
+        files = list(FIXTURES_PATH.glob("**/codemod/*.py"))
+        metafunc.parametrize(
+            "codemod_source_path", files, ids=[file_name.stem for file_name in files]
+        )
+    if "case" in metafunc.fixturenames:
+        exclude_set = expand_error_codes(tuple(DISABLED_BY_DEFAULT))
+        cases = [
+            ("ALL", GET_ALL_ERROR_CODES()),
+            ("ALL,TOR102", GET_ALL_ERROR_CODES()),
+            ("TOR102", {"TOR102"}),
+            ("TOR102,TOR101", {"TOR102", "TOR101"}),
+            ("TOR1,TOR102", {"TOR102", "TOR101", "TOR103", "TOR104", "TOR105"}),
+            (None, set(GET_ALL_ERROR_CODES()) - exclude_set),
+        ]
+        metafunc.parametrize("case,expected", cases, ids=[case for case, _ in cases])
+
+
 def _checker_results(s):
     checker = TorchChecker(None, s)
     return [f"{line}:{col} {msg}" for line, col, msg, _ in checker.run()]
 
 
-def _codemod_results(source_path):
-    with open(source_path) as source:
-        code = source.read()
+def _codemod_results(source_path: Path):
+    code = source_path.read_text()
     config = TorchCodemodConfig(select=list(GET_ALL_ERROR_CODES()))
-    context = TorchCodemod(codemod.CodemodContext(filename=source_path), config)
+    context = TorchCodemod(codemod.CodemodContext(filename=str(source_path)), config)
     new_module = codemod.transform_module(context, code)
     if isinstance(new_module, codemod.TransformSuccess):
         return new_module.code
-    elif isinstance(new_module, codemod.TransformFailure):
+    if isinstance(new_module, codemod.TransformFailure):
         raise new_module.error
 
 
 def test_empty():
     assert _checker_results([""]) == []
 
 
-def test_checker_fixtures():
-    for source_path in FIXTURES_PATH.glob("**/checker/*.py"):
-        LOGGER.info("Testing %s", source_path.relative_to(Path.cwd()))
-        expected_path = str(source_path)[:-2] + "txt"
-        expected_results = []
-        with open(expected_path) as expected:
-            for line in expected:
-                expected_results.append(line.rstrip())
+def test_checker_fixtures(checker_source_path: Path):
+    expected_path = checker_source_path.with_suffix(".txt")
+    expected_results = expected_path.read_text().splitlines()
 
-        with open(source_path) as source:
-            assert _checker_results(source.readlines()) == expected_results
+    assert (
+        _checker_results(checker_source_path.read_text().splitlines(keepends=True))
+        == expected_results
+    )
 
 
-def test_codemod_fixtures():
-    for source_path in FIXTURES_PATH.glob("**/codemod/*.py"):
-        LOGGER.info("Testing %s", source_path.relative_to(Path.cwd()))
-        expected_path = source_path.with_suffix(".py.out")
-        expected_results = expected_path.read_text()
-        assert _codemod_results(source_path) == expected_results
+def test_codemod_fixtures(codemod_source_path: Path):
+    expected_path = codemod_source_path.with_suffix(".py.out")
+    expected_results = expected_path.read_text()
+    assert _codemod_results(codemod_source_path) == expected_results
 
 
 def test_errorcodes_distinct():
     visitors = GET_ALL_VISITORS()
     seen = set()
     for visitor in visitors:
         LOGGER.info("Checking error code for %s", visitor.__class__.__name__)
-        errors = visitor.ERRORS
-        for e in errors:
+        for e in visitor.ERRORS:
             assert e not in seen
             seen.add(e)
 
 
-def test_parse_error_code_str():
-    exclude_set = expand_error_codes(tuple(DISABLED_BY_DEFAULT))
-    cases = [
-        ("ALL", GET_ALL_ERROR_CODES()),
-        ("ALL,TOR102", GET_ALL_ERROR_CODES()),
-        ("TOR102", {"TOR102"}),
-        ("TOR102,TOR101", {"TOR102", "TOR101"}),
-        ("TOR1,TOR102", {"TOR102", "TOR101", "TOR103", "TOR104", "TOR105"}),
-        (None, set(GET_ALL_ERROR_CODES()) - exclude_set),
-    ]
-    for case, expected in cases:
-        assert expected == process_error_code_str(case)
+def test_parse_error_code_str(case, expected):
+    assert process_error_code_str(case) == expected