Add tests for coverage function

Signed-off-by: John Pennycook <john.pennycook@intel.com>

Author: Pennycook

tests/metrics/test_coverage.py

@@ -0,0 +1,49 @@
+# Copyright (C) 2019-2024 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause
+
+import logging
+import math
+import unittest
+
+from codebasin.report import coverage
+
+
+class TestCoverage(unittest.TestCase):
+    """
+    Test computation of coverage.
+    """
+
+    def setUp(self):
+        logging.disable()
+
+    def test_coverage(self):
+        """Check coverage computation for simple setmap."""
+        setmap = {
+            frozenset(["A"]): 1,
+            frozenset(["B"]): 2,
+            frozenset(["A", "B"]): 3,
+            frozenset([]): 4,
+        }
+        used_sloc = 1 + 2 + 3
+        total_sloc = 1 + 2 + 3 + 4
+
+        expected_coverage = used_sloc / total_sloc * 100.0
+        self.assertEqual(coverage(setmap), expected_coverage)
+        self.assertEqual(coverage(setmap, ["A", "B"]), expected_coverage)
+
+        expected_a = (1 + 3) / total_sloc * 100.0
+        self.assertEqual(coverage(setmap, ["A"]), expected_a)
+
+        expected_b = (2 + 3) / total_sloc * 100.0
+        self.assertEqual(coverage(setmap, ["B"]), expected_b)
+
+    def test_null_coverage(self):
+        """Check coverage computation for null cases."""
+        setmap = {
+            frozenset(""): 0,
+        }
+        self.assertTrue(math.isnan(coverage(setmap)))
+
+
+if __name__ == "__main__":
+    unittest.main()