Read simple data cases automatically

CHANGES.md

@@ -62,6 +62,12 @@
 
 <!-- Changes that improve Black's performance. -->
 
+### Testing
+
+<!-- Changes that improve Black's testing process. -->
+
+- Simple cases now read automatically from specified subdirectory (#3034)
+
 ## 22.3.0
 
 ### Preview style

tests/test_black.py

@@ -179,8 +179,8 @@ def test_piping_diff(self) -> None:
             r"(STDIN|STDOUT)\t\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d\.\d\d\d\d\d\d "
             r"\+\d\d\d\d"
         )
-        source, _ = read_data("expression.py")
-        expected, _ = read_data("expression.diff")
+        source, _ = read_data("expression.py", cases_dir="simple_cases")
+        expected, _ = read_data("expression.diff", cases_dir="simple_cases")
         args = [
             "-",
             "--fast",
@@ -197,7 +197,7 @@ def test_piping_diff(self) -> None:
         self.assertEqual(expected, actual)
 
     def test_piping_diff_with_color(self) -> None:
-        source, _ = read_data("expression.py")
+        source, _ = read_data("expression.py", cases_dir="simple_cases")
         args = [
             "-",
             "--fast",
@@ -241,7 +241,7 @@ def test_pep_572_version_detection(self) -> None:
         self.assertIn(black.TargetVersion.PY38, versions)
 
     def test_expression_ff(self) -> None:
-        source, expected = read_data("expression")
+        source, expected = read_data("expression", cases_dir="simple_cases")
         tmp_file = Path(black.dump_to_file(source))
         try:
             self.assertTrue(ff(tmp_file, write_back=black.WriteBack.YES))
@@ -255,8 +255,8 @@ def test_expression_ff(self) -> None:
             black.assert_stable(source, actual, DEFAULT_MODE)
 
     def test_expression_diff(self) -> None:
-        source, _ = read_data("expression.py")
-        expected, _ = read_data("expression.diff")
+        source, _ = read_data("expression.py", cases_dir="simple_cases")
+        expected, _ = read_data("expression.diff", cases_dir="simple_cases")
         tmp_file = Path(black.dump_to_file(source))
         diff_header = re.compile(
             rf"{re.escape(str(tmp_file))}\t\d\d\d\d-\d\d-\d\d "
@@ -281,8 +281,8 @@ def test_expression_diff(self) -> None:
             self.assertEqual(expected, actual, msg)
 
     def test_expression_diff_with_color(self) -> None:
-        source, _ = read_data("expression.py")
-        expected, _ = read_data("expression.diff")
+        source, _ = read_data("expression.py", cases_dir="simple_cases")
+        expected, _ = read_data("expression.diff", cases_dir="simple_cases")
         tmp_file = Path(black.dump_to_file(source))
         try:
             result = BlackRunner().invoke(
@@ -320,7 +320,7 @@ def test_string_quotes(self) -> None:
         black.assert_stable(source, not_normalized, mode=mode)
 
     def test_skip_magic_trailing_comma(self) -> None:
-        source, _ = read_data("expression.py")
+        source, _ = read_data("expression.py", cases_dir="simple_cases")
         expected, _ = read_data("expression_skip_magic_trailing_comma.diff")
         tmp_file = Path(black.dump_to_file(source))
         diff_header = re.compile(
@@ -755,7 +755,7 @@ def test_get_features_used(self) -> None:
         self.assertEqual(black.get_features_used(node), {Feature.NUMERIC_UNDERSCORES})
         node = black.lib2to3_parse("123456\n")
         self.assertEqual(black.get_features_used(node), set())
-        source, expected = read_data("function")
+        source, expected = read_data("function", cases_dir="simple_cases")
         node = black.lib2to3_parse(source)
         expected_features = {
             Feature.TRAILING_COMMA_IN_CALL,
@@ -765,7 +765,7 @@ def test_get_features_used(self) -> None:
         self.assertEqual(black.get_features_used(node), expected_features)
         node = black.lib2to3_parse(expected)
         self.assertEqual(black.get_features_used(node), expected_features)
-        source, expected = read_data("expression")
+        source, expected = read_data("expression", cases_dir="simple_cases")
         node = black.lib2to3_parse(source)
         self.assertEqual(black.get_features_used(node), set())
         node = black.lib2to3_parse(expected)
@@ -939,7 +939,7 @@ def test_check_diff_use_together(self) -> None:
             src1 = (THIS_DIR / "data" / "string_quotes.py").resolve()
             self.invokeBlack([str(src1), "--diff", "--check"], exit_code=1)
             # Files which will not be reformatted.
-            src2 = (THIS_DIR / "data" / "composition.py").resolve()
+            src2 = (THIS_DIR / "data" / "simple_cases" / "composition.py").resolve()
             self.invokeBlack([str(src2), "--diff", "--check"])
             # Multi file command.
             self.invokeBlack([str(src1), str(src2), "--diff", "--check"], exit_code=1)
@@ -1168,7 +1168,7 @@ def test_reformat_one_with_stdin_and_existing_path(self) -> None:
             report = MagicMock()
             # Even with an existing file, since we are forcing stdin, black
             # should output to stdout and not modify the file inplace
-            p = Path(str(THIS_DIR / "data/collections.py"))
+            p = Path(str(THIS_DIR / "data" / "simple_cases" / "collections.py"))
             # Make sure is_file actually returns True
             self.assertTrue(p.is_file())
             path = Path(f"__BLACK_STDIN_FILENAME__{p}")

tests/test_format.py

@@ -1,5 +1,5 @@
 from dataclasses import replace
-from typing import Any, Iterator, List
+from typing import Any, Iterator, List, Optional
 from unittest.mock import patch
 
 import pytest
@@ -12,56 +12,9 @@
     assert_format,
     dump_to_stderr,
     read_data,
+    all_data_cases,
 )
 
-SIMPLE_CASES: List[str] = [
-    "attribute_access_on_number_literals",
-    "beginning_backslash",
-    "bracketmatch",
-    "class_blank_parentheses",
-    "class_methods_new_line",
-    "collections",
-    "comments",
-    "comments2",
-    "comments3",
-    "comments4",
-    "comments5",
-    "comments6",
-    "comments_non_breaking_space",
-    "comment_after_escaped_newline",
-    "composition",
-    "composition_no_trailing_comma",
-    "docstring",
-    "empty_lines",
-    "expression",
-    "fmtonoff",
-    "fmtonoff2",
-    "fmtonoff3",
-    "fmtonoff4",
-    "fmtskip",
-    "fmtskip2",
-    "fmtskip3",
-    "fmtskip4",
-    "fmtskip5",
-    "fmtskip6",
-    "fmtskip7",
-    "fstring",
-    "function",
-    "function2",
-    "function_trailing_comma",
-    "import_spacing",
-    "power_op_spacing",
-    "remove_parens",
-    "slices",
-    "string_prefixes",
-    "torture",
-    "trailing_comma_optional_parens1",
-    "trailing_comma_optional_parens2",
-    "trailing_comma_optional_parens3",
-    "tricky_unicode_symbols",
-    "tupleassign",
-]
-
 PY310_CASES: List[str] = [
     "starred_for_target",
     "pattern_matching_simple",
@@ -141,14 +94,20 @@ def patch_dump_to_file(request: Any) -> Iterator[None]:
         yield
 
 
-def check_file(filename: str, mode: black.Mode, *, data: bool = True) -> None:
-    source, expected = read_data(filename, data=data)
+def check_file(
+    filename: str,
+    mode: black.Mode,
+    *,
+    data: bool = True,
+    cases_dir: Optional[str] = None,
+) -> None:
+    source, expected = read_data(filename, data=data, cases_dir=cases_dir)
     assert_format(source, expected, mode, fast=False)
 
 
-@pytest.mark.parametrize("filename", SIMPLE_CASES)
+@pytest.mark.parametrize("filename", all_data_cases("simple_cases"))
 def test_simple_format(filename: str) -> None:
-    check_file(filename, DEFAULT_MODE)
+    check_file(filename, DEFAULT_MODE, cases_dir="simple_cases")
 
 
 @pytest.mark.parametrize("filename", PREVIEW_CASES)

tests/util.py

@@ -90,12 +90,25 @@ def assertFormatEqual(self, expected: str, actual: str) -> None:
         _assert_format_equal(expected, actual)
 
 
-def read_data(name: str, data: bool = True) -> Tuple[str, str]:
+def all_data_cases(dir_name: str, data: bool = True) -> List[str]:
+    base_dir = DATA_DIR if data else PROJECT_ROOT
+    cases_dir = base_dir / dir_name
+    assert cases_dir.is_dir()
+    return [case_path.stem for case_path in cases_dir.iterdir()]
+
+
+def read_data(
+    name: str, data: bool = True, cases_dir: Optional[str] = None
+) -> Tuple[str, str]:
     """read_data('test_name') -> 'input', 'output'"""
     if not name.endswith((".py", ".pyi", ".out", ".diff")):
         name += ".py"
     base_dir = DATA_DIR if data else PROJECT_ROOT
-    return read_data_from_file(base_dir / name)
+    if cases_dir is not None:
+        base_dir /= cases_dir
+    case_path = base_dir / name
+    assert case_path.is_file(), f"{case_path} is not a file."
+    return read_data_from_file(case_path)
 
 
 def read_data_from_file(file_name: Path) -> Tuple[str, str]: