tests: Run examples as part of test suite

The example code under examples/ also function as valuable tests.
This adds a tests/test_examples.py file that runs each example script
under examples/ as a separate test case.

For the examples, we simply consider a zero exit code to signal that the
examples completed successfully. A non-zero exit causes a test failure.

Author: jherland

tests/test_examples.py

@@ -0,0 +1,10 @@
+from pathlib import Path
+import pytest
+import subprocess
+
+example_scripts = (Path(__file__).parent.parent / "examples").glob("*.py")
+
+
+@pytest.mark.parametrize("script", example_scripts)
+def test_example_script(script):
+    subprocess.run([script], check=True)