Refactor ``find_default_config_files`` (#6067)

Co-authored-by: Pierre Sassoulas <pierre.sassoulas@gmail.com>

1 files changed, 132 insertions, 0 deletions

diff --git a/tests/config/test_find_default_config_files.py b/tests/config/test_find_default_config_files.py
index 04392781b..ca1461bad 100644
--- a/tests/config/test_find_default_config_files.py
+++ b/tests/config/test_find_default_config_files.py
@@ -1,13 +1,145 @@
 # Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 # For details: https://github.com/PyCQA/pylint/blob/main/LICENSE
 # Copyright (c) https://github.com/PyCQA/pylint/blob/main/CONTRIBUTORS.txt
+
+import contextlib
+import importlib
+import os
+import shutil
+import sys
+import tempfile
 from pathlib import Path
+from typing import Iterator
 
 import pytest
 
+from pylint import config, testutils
 from pylint.config.find_default_config_files import _cfg_has_config, _toml_has_config
 
 
+@pytest.fixture
+def pop_pylintrc() -> None:
+    """Remove the PYLINTRC environment variable"""
+    os.environ.pop("PYLINTRC", None)
+
+
+if os.name == "java":
+    if os.name == "nt":
+        HOME = "USERPROFILE"
+    else:
+        HOME = "HOME"
+elif sys.platform == "win32":
+    HOME = "USERPROFILE"
+else:
+    HOME = "HOME"
+
+
+@contextlib.contextmanager
+def fake_home() -> Iterator[None]:
+    """Fake a home directory."""
+    folder = tempfile.mkdtemp("fake-home")
+    old_home = os.environ.get(HOME)
+    try:
+        os.environ[HOME] = folder
+        yield
+    finally:
+        os.environ.pop("PYLINTRC", "")
+        if old_home is None:
+            del os.environ[HOME]
+        else:
+            os.environ[HOME] = old_home
+        shutil.rmtree(folder, ignore_errors=True)
+
+
+@contextlib.contextmanager
+def tempdir() -> Iterator[str]:
+    """Create a temp directory and change the current location to it.
+
+    This is supposed to be used with a *with* statement.
+    """
+    tmp = tempfile.mkdtemp()
+
+    # Get real path of tempfile, otherwise test fail on mac os x
+    current_dir = os.getcwd()
+    os.chdir(tmp)
+    abs_tmp = os.path.abspath(".")
+
+    try:
+        yield abs_tmp
+    finally:
+        os.chdir(current_dir)
+        shutil.rmtree(abs_tmp)
+
+
+@pytest.mark.usefixtures("pop_pylintrc")
+def test_pylintrc() -> None:
+    """Test that the environment variable is checked for existence."""
+    with fake_home():
+        current_dir = os.getcwd()
+        os.chdir(os.path.dirname(os.path.abspath(sys.executable)))
+        try:
+            assert not list(config.find_default_config_files())
+            os.environ["PYLINTRC"] = os.path.join(tempfile.gettempdir(), ".pylintrc")
+            assert not list(config.find_default_config_files())
+            os.environ["PYLINTRC"] = "."
+            assert not list(config.find_default_config_files())
+        finally:
+            os.chdir(current_dir)
+            importlib.reload(config)
+
+
+@pytest.mark.usefixtures("pop_pylintrc")
+def test_pylintrc_parentdir() -> None:
+    """Test that the first pylintrc we find is the first parent directory."""
+    with tempdir() as chroot:
+        chroot_path = Path(chroot)
+        testutils.create_files(
+            [
+                "a/pylintrc",
+                "a/b/__init__.py",
+                "a/b/pylintrc",
+                "a/b/c/__init__.py",
+                "a/b/c/d/__init__.py",
+                "a/b/c/d/e/.pylintrc",
+            ]
+        )
+
+        with fake_home():
+            assert not list(config.find_default_config_files())
+
+        results = {
+            "a": chroot_path / "a" / "pylintrc",
+            "a/b": chroot_path / "a" / "b" / "pylintrc",
+            "a/b/c": chroot_path / "a" / "b" / "pylintrc",
+            "a/b/c/d": chroot_path / "a" / "b" / "pylintrc",
+            "a/b/c/d/e": chroot_path / "a" / "b" / "c" / "d" / "e" / ".pylintrc",
+        }
+        for basedir, expected in results.items():
+            os.chdir(chroot_path / basedir)
+            assert next(config.find_default_config_files()) == expected
+
+
+@pytest.mark.usefixtures("pop_pylintrc")
+def test_pylintrc_parentdir_no_package() -> None:
+    """Test that we don't find a pylintrc in sub-packages."""
+    with tempdir() as chroot:
+        with fake_home():
+            chroot_path = Path(chroot)
+            testutils.create_files(
+                ["a/pylintrc", "a/b/pylintrc", "a/b/c/d/__init__.py"]
+            )
+            assert config.find_pylintrc() is None
+            results = {
+                "a": chroot_path / "a" / "pylintrc",
+                "a/b": chroot_path / "a" / "b" / "pylintrc",
+                "a/b/c": None,
+                "a/b/c/d": None,
+            }
+            for basedir, expected in results.items():
+                os.chdir(chroot_path / basedir)
+                assert next(config.find_default_config_files(), None) == expected
+
+
 @pytest.mark.parametrize(
     "content,expected",
     [