test: add gh-48 regression

Author: tony

tests/regressions/test_gh_issue_48.py

@@ -0,0 +1,165 @@
+"""Regression reproducer for https://github.com/git-pull/gp-libs/issues/48.
+
+Docutils/myst-parser do not know about ``.. doctest::`` (or related) directives
+until :func:`doctest_docutils.setup` registers them.  The Arch Linux packaging
+environment executes ``pytest`` without importing our pytest plugin, so the
+directives are missing and ``DocutilsDocTestFinder`` returns zero doctests.
+
+These tests intentionally exercise that scenario by purging the docutils
+directive registry before running the finder.
+"""
+
+from __future__ import annotations
+
+import doctest
+import textwrap
+import typing as t
+
+import pytest
+from docutils.parsers.rst import directives
+
+import doctest_docutils
+
+if t.TYPE_CHECKING:
+    import pathlib
+
+FixtureFileDict = dict[str, str]
+
+
+class GhIssue48Fixture(t.NamedTuple):
+    """Test fixture for reproducing GH-48."""
+
+    test_id: str
+    files: FixtureFileDict
+    tests_found: int
+
+
+FIXTURES = [
+    GhIssue48Fixture(
+        test_id="reST-doctest_directive",
+        files={
+            "example.rst": textwrap.dedent(
+                """
+.. doctest::
+
+   >>> 4 + 4
+   8
+                """,
+            ),
+        },
+        tests_found=1,
+    ),
+    GhIssue48Fixture(
+        test_id="MyST-doctest_directive-backticks",
+        files={
+            "example.md": textwrap.dedent(
+                """
+```{doctest}
+
+    >>> 4 + 4
+    8
+```
+                """,
+            ),
+        },
+        tests_found=1,
+    ),
+    GhIssue48Fixture(
+        test_id="MyST-doctest_block-python--sphinx-inline-tabs",
+        files={
+            "example.md": textwrap.dedent(
+                """
+````{tab} example tab
+```python
+>>> 4 + 4
+8
+```
+````
+
+````{tab} example second
+```python
+>>> 4 + 2
+6
+```
+````
+                """,
+            ),
+        },
+        tests_found=2,
+    ),
+]
+
+
+def _directive_registry() -> dict[str, t.Any]:
+    """Return the docutils directive registry with typing hints."""
+    # Access via __dict__ keeps Ruff happy and satisfies mypy with cast.
+    return t.cast(dict[str, t.Any], directives.__dict__["_directives"])
+
+
+@pytest.fixture()
+def purge_doctest_directives() -> t.Iterator[None]:
+    """Remove doctest-related directives to mimic Arch packaging env."""
+    saved: dict[str, t.Any] = {}
+    target_directives = ("doctest", "testsetup", "testcleanup", "tab")
+    registry = _directive_registry()
+    for name in target_directives:
+        if name in registry:
+            saved[name] = registry[name]
+            registry.pop(name, None)
+    try:
+        yield
+    finally:
+        registry.update(saved)
+
+
+@pytest.mark.parametrize(
+    GhIssue48Fixture._fields,
+    FIXTURES,
+    ids=[fixture.test_id for fixture in FIXTURES],
+)
+@pytest.mark.parametrize("file_path_mode", ["relative", "absolute"])
+@pytest.mark.xfail(
+    reason="GH-48: directives are not registered unless doctest_docutils.setup() runs",
+    strict=False,
+)
+def test_docutils_doctest_finder_without_registered_directives(
+    purge_doctest_directives: None,
+    tmp_path: pathlib.Path,
+    monkeypatch: pytest.MonkeyPatch,
+    test_id: str,
+    files: FixtureFileDict,
+    tests_found: int,
+    file_path_mode: str,
+) -> None:
+    """Recreate Arch Linux failure by skipping doctest_docutils.setup()."""
+    tests_path = tmp_path / "tests"
+    tests_path.mkdir()
+    first_test_key = next(iter(files.keys()))
+    first_test_filename: str | pathlib.Path = first_test_key
+
+    if file_path_mode == "absolute":
+        first_test_filename = tests_path / first_test_filename
+    elif file_path_mode != "relative":  # pragma: no cover - defensive guard
+        error_message = f"Unsupported file_path_mode: {file_path_mode}"
+        raise ValueError(error_message)
+
+    for file_name, text in files.items():
+        (tests_path / file_name).write_text(text, encoding="utf-8")
+
+    if file_path_mode == "relative":
+        monkeypatch.chdir(tests_path)
+
+    finder = doctest_docutils.DocutilsDocTestFinder()
+    text, _ = doctest._load_testfile(  # type: ignore[attr-defined]
+        str(first_test_filename),
+        package=None,
+        module_relative=False,
+        encoding="utf-8",
+    )
+    tests = finder.find(text, str(first_test_filename))
+    tests.sort(key=lambda doctest_case: doctest_case.name)
+
+    assert len(tests) == tests_found
+
+    for test in tests:
+        doctest.DebugRunner(verbose=False).run(test)