Fix execution outside git repositories

src/ansiblelint/file_utils.py

@@ -252,7 +252,7 @@ def discover_lintables(options: Namespace) -> Dict[str, Any]:
     return OrderedDict.fromkeys(sorted(out))
 
 
-def guess_project_dir(config_file: str) -> str:
+def guess_project_dir(config_file: Optional[str]) -> str:
     """Return detected project dir or current working directory."""
     path = None
     if config_file is not None:
@@ -267,7 +267,7 @@ def guess_project_dir(config_file: str) -> str:
                 stderr=subprocess.PIPE,
                 stdout=subprocess.PIPE,
                 universal_newlines=True,
-                check=False,
+                check=True,
             )
 
             path = result.stdout.splitlines()[0]

test/TestUtils.py

@@ -43,10 +43,13 @@
     Lintable,
     expand_path_vars,
     expand_paths_vars,
+    guess_project_dir,
     normpath,
 )
 from ansiblelint.testing import run_ansible_lint
 
+from .conftest import cwd
+
 
 @pytest.mark.parametrize(
     ('string', 'expected_cmd', 'expected_args', 'expected_kwargs'),
@@ -510,3 +513,10 @@ def test_nested_items() -> None:
         ("list-item", "orange", "fruits"),
     ]
     assert list(utils.nested_items(data)) == items
+
+
+def test_guess_project_dir(tmp_path: Path) -> None:
+    """Verify guess_project_dir()."""
+    with cwd(str(tmp_path)):
+        result = guess_project_dir(None)
+        assert result == str(tmp_path)

test/conftest.py

@@ -0,0 +1,14 @@
+import os
+from contextlib import contextmanager
+from typing import Iterator
+
+
+@contextmanager
+def cwd(path: str) -> Iterator[None]:
+    """Context manager for chdir."""
+    oldpwd = os.getcwd()
+    os.chdir(path)
+    try:
+        yield
+    finally:
+        os.chdir(oldpwd)