add pytest plugin

Author: patricktnast

setup.py

@@ -49,6 +49,7 @@
         "vivarium_build_utils>=2.0.1,<3.0.0",
         "pyarrow",
         "seaborn",
+        "layered-config-tree",
         # Type stubs
         "types-setuptools",
     ]
@@ -69,6 +70,7 @@
     test_requirements = [
         "vivarium_dependencies[pytest]",
         "pytest-check",
+        "vivarium_testing_utils",
     ]
 
     doc_requirements = [
@@ -124,6 +126,9 @@
             + lint_requirements
             + validation_requirements,
         },
+        entry_points={
+            "pytest11": ["vivarium_testing_utils = vivarium_testing_utils.pytest_plugin"],
+        },
         zip_safe=False,
         use_scm_version={
             "write_to": "src/vivarium_testing_utils/_version.py",

src/vivarium_testing_utils/pytest_plugin.py

@@ -0,0 +1,36 @@
+"""Pytest plugin providing common fixtures for vivarium projects.
+
+This module is automatically loaded by pytest when vivarium_testing_utils is installed,
+via the pytest11 entry point defined in setup.py.
+"""
+
+import pytest
+from layered_config_tree import LayeredConfigTree
+from pytest_mock import MockerFixture
+
+
+@pytest.fixture
+def no_gbd_cache(mocker: MockerFixture) -> None:
+    """Disable vivarium_gbd_access caching for test isolation.
+
+    This fixture mocks ``vivarium_gbd_access.utilities.get_input_config`` to return
+    a configuration with ``cache_data`` set to False, ensuring that tests always
+    pull fresh data rather than using cached results.
+
+    Note that this fixture does NOT use ``autouse=True``. If you want it to apply
+    to all tests in a module or package, create a wrapper fixture in your conftest.py:
+
+    .. code-block:: python
+
+        import pytest
+
+        @pytest.fixture(autouse=True)
+        def no_cache(no_gbd_cache):
+            '''Apply no_gbd_cache to all tests in this module.'''
+            pass
+
+    """
+    mocker.patch(
+        "vivarium_gbd_access.utilities.get_input_config",
+        return_value=LayeredConfigTree({"input_data": {"cache_data": False}}),
+    )