style: Precommit hook for gtest naming (#8026)

Co-authored-by: Bart <bthomee@users.noreply.github.com>

bin/pre-commit/fix_gtest_names.py

@@ -0,0 +1,144 @@
+#!/usr/bin/env python3
+
+"""
+Rewrites gtest names to the required style in this project: the suite name is
+CamelCase, the test-case name is snake_case.
+
+    TEST(SuiteName, test_case_name)
+
+The gtest `DISABLED_` prefix is kept verbatim on either name.
+
+Both conversions fold acronyms the way a reader expects:
+`SetAndResetAccountTxnID` -> `set_and_reset_account_txn_id`, not
+`set_and_reset_account_txn_i_d`.
+
+The first argument of `TEST_F`, `TEST_P`, `TYPED_TEST` and `TYPED_TEST_P` is a
+fixture class rather than a free identifier, so rewriting it here would leave
+the class it names behind. Those are reported for a human to rename (clang-tidy
+checks the class declaration itself, via readability-identifier-naming).
+
+Usage: ./bin/pre-commit/fix_gtest_names.py <file1> <file2> ...
+"""
+
+import re
+import sys
+from collections import Counter
+from pathlib import Path
+
+# A test-case definition, `MACRO(SuiteOrFixture, TestName)`, anchored at the
+# start of a line so that commented-out definitions and project macros that
+# merely look similar (`TEST_EXPECT(...)`) are left alone. The `\s*` between
+# arguments allows for a definition clang-format wrapped over several lines.
+PATTERN = re.compile(
+    r"(?P<head>^[ \t]*(?P<macro>TYPED_TEST_P|TYPED_TEST|TEST_F|TEST_P|TEST)\s*\(\s*)"
+    r"(?P<suite>\w+)(?P<mid>\s*,\s*)(?P<name>\w+)(?P<tail>\s*\))",
+    re.MULTILINE,
+)
+
+# The macros whose first argument names a fixture class, not a free identifier.
+FIXTURE_MACROS = ("TEST_F", "TEST_P", "TYPED_TEST", "TYPED_TEST_P")
+
+DISABLED = "DISABLED_"
+
+ACRONYM_BOUNDARY = re.compile(r"([A-Z]+)([A-Z][a-z])")
+WORD_BOUNDARY = re.compile(r"([a-z\d])([A-Z])")
+
+
+def _split_disabled(name: str) -> tuple[str, str]:
+    """Splits off gtest's `DISABLED_` prefix, which is kept verbatim."""
+    if name.startswith(DISABLED):
+        return DISABLED, name[len(DISABLED) :]
+    return "", name
+
+
+def snake_case(name: str) -> str:
+    """Returns the name in snake_case, leaving acronyms whole.
+
+    `SetAndResetAccountTxnID` -> `set_and_reset_account_txn_id`,
+    `parseStatRSSkB` -> `parse_stat_rs_sk_b`.
+    """
+    prefix, core = _split_disabled(name)
+    core = ACRONYM_BOUNDARY.sub(r"\1_\2", core)
+    return prefix + WORD_BOUNDARY.sub(r"\1_\2", core).lower()
+
+
+def camel_case(name: str) -> str:
+    """Returns the name in CamelCase, capitalizing each underscored word.
+
+    Only the letters that have to change are touched, so acronyms survive: a
+    conversion that went via snake_case would turn `SHAMapTest` into
+    `ShaMapTest`, whereas here it is already CamelCase and stays put.
+    `json_value` -> `JsonValue`, `parseStatRSSkB` -> `ParseStatRSSkB`.
+    """
+    prefix, core = _split_disabled(name)
+    return prefix + "".join(w[:1].upper() + w[1:] for w in core.split("_") if w)
+
+
+def _corrected(match: re.Match) -> tuple[str, str]:
+    """Returns the suite and test-case names this definition should end up with."""
+    suite = match["suite"]
+    return (
+        suite if match["macro"] in FIXTURE_MACROS else camel_case(suite),
+        snake_case(match["name"]),
+    )
+
+
+def fix_source(text: str) -> tuple[str, list[str]]:
+    """Returns the corrected text and one `line: message` report per bad name."""
+    # gtest joins the suite and test names into one class name, so two test
+    # cases whose joined names agree cannot coexist: `TEST(a, b_c)` and
+    # `TEST(a_b, c)` both define `a_b_c_Test`. A rename that would introduce
+    # such a clash is reported for a human instead of applied.
+    joined = Counter("_".join(_corrected(m)) for m in PATTERN.finditer(text))
+    reports = []
+
+    def rewrite(match: re.Match) -> str:
+        suite, name = match["suite"], match["name"]
+        new_suite, new_name = _corrected(match)
+        line = text.count("\n", 0, match.start()) + 1
+
+        if match["macro"] in FIXTURE_MACROS and camel_case(suite) != suite:
+            reports.append(
+                f"{line}: fixture '{suite}' is not CamelCase: rename the class "
+                f"to '{camel_case(suite)}' by hand"
+            )
+        if (new_suite, new_name) == (suite, name):
+            return match[0]
+        if joined[f"{new_suite}_{new_name}"] > 1:
+            reports.append(
+                f"{line}: cannot rename '{suite}, {name}' to '{new_suite}, "
+                f"{new_name}': another test case already generates that name"
+            )
+            return match[0]
+        if new_suite != suite:
+            reports.append(f"{line}: renamed suite '{suite}' to '{new_suite}'")
+        if new_name != name:
+            reports.append(f"{line}: renamed test case '{name}' to '{new_name}'")
+        return match["head"] + new_suite + match["mid"] + new_name + match["tail"]
+
+    return PATTERN.sub(rewrite, text), reports
+
+
+def fix_names(path: Path) -> bool:
+    """Corrects one file's gtest names, reporting each on stdout."""
+    original = path.read_text(encoding="utf-8")
+    fixed, reports = fix_source(original)
+    for report in reports:
+        print(f"{path}:{report}")
+    if fixed != original:
+        path.write_text(fixed, encoding="utf-8")
+    return not reports
+
+
+def main() -> int:
+    files = [Path(f) for f in sys.argv[1:]]
+    success = True
+
+    for path in files:
+        success &= fix_names(path)
+
+    return 0 if success else 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())

bin/pre-commit/test_fix_gtest_names.py

@@ -0,0 +1,259 @@
+#!/usr/bin/env python3
+"""
+Tests for fix_gtest_names.py.
+
+Run directly (no test framework needed):
+    ./bin/pre-commit/test_fix_gtest_names.py
+or under pytest:
+    pytest bin/pre-commit/test_fix_gtest_names.py
+"""
+
+import sys
+import textwrap
+
+from fix_gtest_names import camel_case, fix_source, snake_case
+
+
+def dedent(text: str) -> str:
+    """Removes a fixture's common indentation and its leading newline.
+
+    Lets fixtures be written as indented triple-quoted here-docs while keeping
+    honest 1-based line numbers.
+    """
+    return textwrap.dedent(text).lstrip("\n")
+
+
+def fixed(text: str) -> str:
+    return fix_source(dedent(text))[0]
+
+
+def reports(text: str) -> list[str]:
+    return fix_source(dedent(text))[1]
+
+
+# --- conversion --------------------------------------------------------------
+
+
+def test_snake_case_conversion() -> None:
+    assert snake_case("BadInputs") == "bad_inputs"
+    assert snake_case("mulDiv") == "mul_div"
+    assert snake_case("already_snake") == "already_snake"
+    assert snake_case("base64") == "base64"
+
+
+def test_snake_case_keeps_acronyms_whole() -> None:
+    assert snake_case("SetAndResetAccountTxnID") == "set_and_reset_account_txn_id"
+    assert snake_case("XRPToIOU") == "xrp_to_iou"
+    assert snake_case("STAmountMath") == "st_amount_math"
+
+
+def test_camel_case_conversion() -> None:
+    assert camel_case("json_value") == "JsonValue"
+    assert camel_case("mulDiv") == "MulDiv"
+    assert camel_case("scope") == "Scope"
+    assert camel_case("base64") == "Base64"
+
+
+def test_camel_case_leaves_acronyms_alone() -> None:
+    # A snake_case round-trip would give `ShaMapTest` / `ParseStatmRsSkB` here.
+    assert camel_case("SHAMapTest") == "SHAMapTest"
+    assert camel_case("parseStatmRSSkB") == "ParseStatmRSSkB"
+    assert camel_case("XRPAmount") == "XRPAmount"
+    assert camel_case("CSPRNG") == "CSPRNG"
+
+
+def test_disabled_prefix_preserved() -> None:
+    assert snake_case("DISABLED_FooBar") == "DISABLED_foo_bar"
+    assert snake_case("DISABLED_foo_bar") == "DISABLED_foo_bar"
+    assert snake_case("DISABLED_") == "DISABLED_"
+    assert camel_case("DISABLED_foo_bar") == "DISABLED_FooBar"
+    assert camel_case("DISABLED_") == "DISABLED_"
+
+
+# --- what counts as a test definition ---------------------------------------
+
+
+def test_all_macros_recognized() -> None:
+    code = """
+    TEST(Suite, oneName)
+    TEST_F(Fixture, twoName)
+    TEST_P(Fixture, threeName)
+    TYPED_TEST(Fixture, fourName)
+    TYPED_TEST_P(Fixture, fiveName)
+    """
+    assert fixed(code) == dedent("""
+        TEST(Suite, one_name)
+        TEST_F(Fixture, two_name)
+        TEST_P(Fixture, three_name)
+        TYPED_TEST(Fixture, four_name)
+        TYPED_TEST_P(Fixture, five_name)
+        """)
+
+
+def test_conforming_definitions_untouched() -> None:
+    code = """
+    TEST(AccountSet, bad_inputs)
+    TEST_F(MutexMakeTest, default_constructor)
+    TEST(SHAMap, DISABLED_slow_path)
+    """
+    assert reports(code) == []
+    assert fixed(code) == dedent(code)
+
+
+def test_lookalikes_ignored() -> None:
+    code = """
+    // TEST(Suite, notATest)
+    TEST_EXPECT(someCall())
+    TEST_EXPECTS(amount == value, amount.getText())
+    INSTANTIATE_TEST_SUITE_P(Prefix, Fixture, testValues());
+    auto x = TEST(Suite, notATest);
+    TYPED_TEST_SUITE(Fixture, MyTypes);
+    """
+    assert reports(code) == []
+    assert fixed(code) == dedent(code)
+
+
+def test_indented_and_wrapped_definitions() -> None:
+    code = """
+    namespace ripple {
+        TEST(Suite, indentedName)
+    }
+    TEST_F(
+        SomeVeryLongFixtureName,
+        wrappedName)
+    """
+    assert fixed(code) == dedent("""
+        namespace ripple {
+            TEST(Suite, indented_name)
+        }
+        TEST_F(
+            SomeVeryLongFixtureName,
+            wrapped_name)
+        """)
+
+
+# --- rewriting --------------------------------------------------------------
+
+
+def test_only_the_two_names_are_rewritten() -> None:
+    code = """
+    TEST(mulDiv, mulDiv)
+    {
+        auto const mulDiv = 1;  // mulDiv stays
+    }
+    """
+    assert fixed(code) == dedent("""
+        TEST(MulDiv, mul_div)
+        {
+            auto const mulDiv = 1;  // mulDiv stays
+        }
+        """)
+
+
+def test_suite_name_camel_cased() -> None:
+    code = """
+    TEST(json_value, limits)
+    TEST(scope, ScopeExit)
+    """
+    assert reports(code) == [
+        "1: renamed suite 'json_value' to 'JsonValue'",
+        "2: renamed suite 'scope' to 'Scope'",
+        "2: renamed test case 'ScopeExit' to 'scope_exit'",
+    ]
+    assert fixed(code) == dedent("""
+        TEST(JsonValue, limits)
+        TEST(Scope, scope_exit)
+        """)
+
+
+def test_fixture_reported_but_not_renamed() -> None:
+    # The first argument names a class, so only a human (or clang-tidy) can
+    # rename it; the test-case name is still fixed.
+    code = """
+    TEST_F(my_fixture, someTest)
+    """
+    assert reports(code) == [
+        "1: fixture 'my_fixture' is not CamelCase: rename the class to "
+        "'MyFixture' by hand",
+        "1: renamed test case 'someTest' to 'some_test'",
+    ]
+    assert fixed(code) == dedent("""
+        TEST_F(my_fixture, some_test)
+        """)
+
+
+def test_reports_carry_line_numbers() -> None:
+    code = """
+    #include <foo.h>
+
+    TEST(Suite, firstName)
+
+    TEST(Suite, secondName)
+    """
+    assert reports(code) == [
+        "3: renamed test case 'firstName' to 'first_name'",
+        "5: renamed test case 'secondName' to 'second_name'",
+    ]
+
+
+# --- collisions -------------------------------------------------------------
+
+
+def test_collision_reported_and_not_applied() -> None:
+    # Both would define `Suite_mul_div_Test`.
+    code = """
+    TEST(Suite, mulDiv)
+    TEST(Suite, mul_div)
+    """
+    assert reports(code) == [
+        "1: cannot rename 'Suite, mulDiv' to 'Suite, mul_div': another test "
+        "case already generates that name"
+    ]
+    assert fixed(code) == dedent(code)
+
+
+def test_collision_between_converging_suites() -> None:
+    # Both suites camel-case to `SuiteA`, so both would define
+    # `SuiteA_one_test_Test`.
+    code = """
+    TEST(SuiteA, oneTest)
+    TEST(Suite_a, one_test)
+    """
+    assert [r.split(":")[1].strip() for r in reports(code)] == [
+        "cannot rename 'SuiteA, oneTest' to 'SuiteA, one_test'",
+        "cannot rename 'Suite_a, one_test' to 'SuiteA, one_test'",
+    ]
+    assert fixed(code) == dedent(code)
+
+
+def test_same_name_in_different_suites_is_not_a_collision() -> None:
+    code = """
+    TEST(SuiteOne, mulDiv)
+    TEST(SuiteTwo, mulDiv)
+    """
+    assert fixed(code) == dedent("""
+        TEST(SuiteOne, mul_div)
+        TEST(SuiteTwo, mul_div)
+        """)
+
+
+def main() -> int:
+    tests = sorted(
+        (name, fn)
+        for name, fn in globals().items()
+        if name.startswith("test_") and callable(fn)
+    )
+    failed = 0
+    for name, fn in tests:
+        try:
+            fn()
+            print(f"PASS {name}")
+        except AssertionError as exc:
+            failed += 1
+            print(f"FAIL {name}: {exc!r}")
+    print(f"\n{len(tests) - failed}/{len(tests)} passed")
+    return 1 if failed else 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())