feat: Find Compose files

src/pytest_docker/plugin.py

@@ -149,12 +149,30 @@ def docker_compose_command() -> str:
     return "docker compose"
 
 
+def _find_compose_file(basedir: Path) -> Optional[Path]:
+    # Search for well-known filenames, in the order defined by the compose docs.
+    # https://docs.docker.com/compose/intro/compose-application-model/#the-compose-file
+    names = [
+        "compose.yaml",
+        "compose.yml",
+        "docker-compose.yaml",
+        "docker-compose.yml",
+    ]
+    paths = (basedir / filename for filename in names)
+    exisiting_paths = (path for path in paths if path.is_file())
+
+    return next(exisiting_paths, None)
+
+
 @pytest.fixture(scope=containers_scope)
-def docker_compose_file(pytestconfig: Any) -> Union[List[str], str]:
-    """Get an absolute path to the  `docker-compose.yml` file. Override this
-    fixture in your tests if you need a custom location."""
+def docker_compose_file(pytestconfig: Config) -> Union[List[str], str]:
+    """Get an absolute path to the compose file. Override this fixture in your tests
+    if you need a custom location."""
+
+    tests_dir = Path(pytestconfig.rootpath) / "tests"
+    fallback_path = tests_dir / "docker-compose.yml"
 
-    return os.path.join(str(pytestconfig.rootdir), "tests", "docker-compose.yml")
+    return str(_find_compose_file(tests_dir) or fallback_path)
 
 
 @pytest.fixture(scope=containers_scope)

tests/test_fixtures.py

@@ -1,15 +1,61 @@
-import os.path
+import os
+from pathlib import Path
 from typing import List
 
 import pytest
 from _pytest.fixtures import FixtureRequest
 from _pytest.pytester import Pytester
 
-HERE = os.path.dirname(os.path.abspath(__file__))
 
+@pytest.fixture
+def tests_dir(pytester: Pytester) -> Path:
+    dir = Path(pytester.path) / "tests"
+    dir.mkdir()
+    return dir
+
+
+@pytest.fixture(params=[[]])
+def tests_dir_contents(tests_dir: Path, request: FixtureRequest) -> List[Path]:
+    filenames: List[str] = getattr(request, "param", [])
+    paths = [tests_dir / filename for filename in filenames]
+    for path in paths:
+        path.touch()
+
+    return paths
+
+
+@pytest.mark.parametrize(
+    ("tests_dir_contents", "expected_compose_file"),
+    [
+        (
+            [
+                "compose.yaml",
+                "compose.yml",
+                "docker-compose.yaml",
+                "docker-compose.yml",
+            ],
+            "compose.yaml",
+        ),
+        (["compose.yml", "docker-compose.yaml", "docker-compose.yml"], "compose.yml"),
+        (["docker-compose.yaml", "docker-compose.yml"], "docker-compose.yaml"),
+        (["docker-compose.yml"], "docker-compose.yml"),
+        ([], "docker-compose.yml"),
+    ],
+    indirect=["tests_dir_contents"],
+)
+@pytest.mark.usefixtures("tests_dir_contents")
+def test_docker_compose_file(
+    pytester: Pytester, expected_compose_file: str, tests_dir: Path
+) -> None:
+    pytester.makepyfile(
+        f"""
+        def test_docker_compose_file(docker_compose_file):
+            assert docker_compose_file == "{tests_dir}/{expected_compose_file}"
+    """
+    )
 
-def test_docker_compose_file(docker_compose_file: str) -> None:
-    assert docker_compose_file == os.path.join(HERE, "docker-compose.yml")
+    result = pytester.runpytest()
+    result.assert_outcomes(passed=1)
 
 
 def test_docker_compose_project(docker_compose_project_name: str) -> None: