feat: add unit test fixtures for manifest-only connectors to CDK (#121)

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: ChristoGrab

airbyte_cdk/test/utils/manifest_only_fixtures.py

@@ -0,0 +1,60 @@
+# Copyright (c) 2024 Airbyte, Inc., all rights reserved.
+
+
+import importlib.util
+from pathlib import Path
+from types import ModuleType
+from typing import Optional
+
+import pytest
+
+# The following fixtures are used to load a manifest-only connector's components module and manifest file.
+# They can be accessed from any test file in the connector's unit_tests directory by importing them as follows:
+
+# from airbyte_cdk.test.utils.manifest_only_fixtures import components_module, connector_dir, manifest_path
+
+# individual components can then be referenced as: components_module.<CustomComponentClass>
+
+
+@pytest.fixture(scope="session")
+def connector_dir(request: pytest.FixtureRequest) -> Path:
+    """Return the connector's root directory."""
+
+    current_dir = Path(request.config.invocation_params.dir)
+
+    # If the tests are run locally from the connector's unit_tests directory, return the parent (connector) directory
+    if current_dir.name == "unit_tests":
+        return current_dir.parent
+    # In CI, the tests are run from the connector directory itself
+    return current_dir
+
+
+@pytest.fixture(scope="session")
+def components_module(connector_dir: Path) -> Optional[ModuleType]:
+    """Load and return the components module from the connector directory.
+
+    This assumes the components module is located at <connector_dir>/components.py.
+    """
+    components_path = connector_dir / "components.py"
+    if not components_path.exists():
+        return None
+
+    components_spec = importlib.util.spec_from_file_location("components", components_path)
+    if components_spec is None:
+        return None
+
+    components_module = importlib.util.module_from_spec(components_spec)
+    if components_spec.loader is None:
+        return None
+
+    components_spec.loader.exec_module(components_module)
+    return components_module
+
+
+@pytest.fixture(scope="session")
+def manifest_path(connector_dir: Path) -> Path:
+    """Return the path to the connector's manifest file."""
+    path = connector_dir / "manifest.yaml"
+    if not path.exists():
+        raise FileNotFoundError(f"Manifest file not found at {path}")
+    return path