From 7ed95cdf4825702e14f94e4c8cb42894fc2a8dee Mon Sep 17 00:00:00 2001
From: Toby Jennings <tobyj@slac.stanford.edu>
Date: Mon, 16 Dec 2024 11:15:54 -0600
Subject: [PATCH] chore(test): Add test for coverage

---
 python/lsst/ctrl/mpexec/cli/cmd/commands.py |  3 ++-
 tests/test_cliScript.py                     | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/python/lsst/ctrl/mpexec/cli/cmd/commands.py b/python/lsst/ctrl/mpexec/cli/cmd/commands.py
index bf49f7ad..6ca498a9 100644
--- a/python/lsst/ctrl/mpexec/cli/cmd/commands.py
+++ b/python/lsst/ctrl/mpexec/cli/cmd/commands.py
@@ -29,6 +29,7 @@
 from collections.abc import Iterator, Sequence
 from contextlib import contextmanager
 from functools import partial
+from importlib import import_module
 from tempfile import NamedTemporaryFile
 from typing import Any
 
@@ -146,7 +147,7 @@ def coverage_context(kwargs: dict[str, Any]) -> Iterator[None]:
         return
     # Lazily import coverage only when we might need it
     try:
-        import coverage
+        coverage = import_module("coverage")
     except ModuleNotFoundError:
         raise click.ClickException("coverage was requested but the coverage package is not installed.")
     with NamedTemporaryFile("w") as rcfile:
diff --git a/tests/test_cliScript.py b/tests/test_cliScript.py
index f05c4771..e6c92637 100644
--- a/tests/test_cliScript.py
+++ b/tests/test_cliScript.py
@@ -28,10 +28,12 @@
 import os
 import tempfile
 import unittest
+import unittest.mock
 
 import click
 import lsst.utils.tests
 from lsst.ctrl.mpexec.cli import opt, script
+from lsst.ctrl.mpexec.cli.cmd.commands import coverage_context
 from lsst.ctrl.mpexec.cli.pipetask import cli as pipetaskCli
 from lsst.ctrl.mpexec.showInfo import ShowInfo
 from lsst.daf.butler.cli.utils import LogCliRunner, clickResultMsg
@@ -203,6 +205,25 @@ def cli(**kwargs):
         self.assertNotEqual(result.exit_code, 0)
 
 
+class CoverageTestCase(unittest.TestCase):
+    """Test coverage context manager."""
+
+    @unittest.mock.patch.dict("sys.modules", coverage=unittest.mock.MagicMock())
+    def testWithCoverage(self):
+        """Test that the coverage context manager runs when invoked."""
+        with coverage_context({"coverage": True}):
+            self.assertTrue(True)
+
+    @unittest.mock.patch("lsst.ctrl.mpexec.cli.cmd.commands.import_module", side_effect=ModuleNotFoundError())
+    def testWithMissingCoverage(self, mock_import):
+        """Test that the coverage context manager complains when coverage is
+        not available.
+        """
+        with self.assertRaises(click.exceptions.ClickException):
+            with coverage_context({"coverage": True}):
+                pass
+
+
 if __name__ == "__main__":
     lsst.utils.tests.init()
     unittest.main()