add functions for running scripts to conftest

Author: cadenmyers13

tests/conftest.py

@@ -1,8 +1,12 @@
+import importlib.util
 import json
 from pathlib import Path
 
+import matplotlib
 import pytest
 
+__examples_dir__ = Path(__file__).parent.parent / "docs" / "examples"
+
 
 @pytest.fixture
 def user_filesystem(tmp_path):
@@ -17,3 +21,24 @@ def user_filesystem(tmp_path):
         json.dump(home_config_data, f)
 
     yield tmp_path
+
+
+@pytest.fixture(scope="session", autouse=True)
+def use_headless_matplotlib():
+    """Force matplotlib to use a headless backend during tests."""
+    matplotlib.use("Agg")
+
+
+def load_module_from_path(path: Path):
+    """Load a module given an absolute Path."""
+    spec = importlib.util.spec_from_file_location(path.stem, path)
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+def run_cmi_script(script_path: Path):
+    """General runner for example scripts with a main()."""
+    module = load_module_from_path(script_path)
+    assert hasattr(module, "main"), f"{script_path} has no main() function"
+    module.main()