Add pytest unit testing framework

tests/utils/fixtures.py

@@ -0,0 +1,30 @@
+"""This module provides utility fixtures for testing."""
+from typing import Tuple
+
+from _pytest.fixtures import FixtureRequest
+import pytest
+
+
+@pytest.fixture(params=[True, False])
+def boolean(request: FixtureRequest) -> bool:
+    return request.param
+
+
+@pytest.fixture
+def boolean1(boolean: bool) -> Tuple[bool]:
+    return (boolean,)
+
+
+@pytest.fixture(params=[True, False])
+def boolean2(request: FixtureRequest, boolean: bool) -> Tuple[bool, bool]:
+    return (boolean, request.param)
+
+
+@pytest.fixture(params=[True, False])
+def boolean3(
+    request: FixtureRequest, boolean2: Tuple[bool, bool]
+) -> Tuple[bool, bool, bool]:
+    return (boolean2[0], boolean2[1], request.param)
+
+
+# …