Add test of logic for selecting worflow.

tests/conftest.py

@@ -0,0 +1,63 @@
+"""Fixtures for all test suites."""
+
+import logging
+import re
+from collections.abc import Iterable
+from contextlib import contextmanager
+from typing import Optional
+
+import pytest
+
+
+@pytest.fixture
+def check_side_effect(caplog):
+    """Supply a context manager for checking code either logs, raises an error, or doesn't."""
+
+    @contextmanager
+    def _checker(
+        side_effect: Optional[type | int | Iterable[int]],
+        match: Optional[str | Iterable[str]] = None,
+    ) -> None:
+        """Check the code within this context has the expected side effect.
+
+        :param side_effect: The side effect of the code within this context. An int
+            should be a logging level number, or a list of level numbers if multiple
+            logs are expected.
+        :param match: Optionally a match regex for raises or the logger, can be a list
+            if side effect is a list of levels.
+        """
+        # If the side effect is an exception
+        if isinstance(side_effect, type) and issubclass(side_effect, BaseException):
+            with pytest.raises(side_effect, match=match):
+                yield
+            return
+
+        # If the side effect is None or logging
+        caplog.clear()
+
+        with caplog.at_level(logging.INFO):
+            yield
+
+        if side_effect is None:
+            # No side effect
+            assert caplog.records == []
+        elif isinstance(side_effect, Iterable):
+            # Multiple logs
+            if match is not None:
+                assert isinstance(match, Iterable)
+                assert len(match) == len(side_effect)
+            assert len(caplog.records) == len(side_effect)
+            for i, level in enumerate(side_effect):
+                record = caplog.records[i]
+                assert record.levelno == level
+                if match is not None:
+                    assert re.match(match[i], record.message) is not None
+        else:
+            # Single log
+            assert len(caplog.records) == 1
+            record = caplog.records[0]
+            assert record.levelno == side_effect
+            if match is not None:
+                assert re.match(match, record.message) is not None
+
+    return _checker