Add tests for average_coverage function

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

Author: Pennycook

tests/metrics/test_coverage.py

@@ -5,7 +5,7 @@
 import math
 import unittest
 
-from codebasin.report import coverage
+from codebasin.report import average_coverage, coverage
 
 
 class TestCoverage(unittest.TestCase):
@@ -37,12 +37,38 @@ def test_coverage(self):
         expected_b = (2 + 3) / total_sloc * 100.0
         self.assertEqual(coverage(setmap, ["B"]), expected_b)
 
+    def test_average_coverage(self):
+        """Check average coverage computation for simple setmap."""
+        setmap = {
+            frozenset(["A"]): 1,
+            frozenset(["B"]): 2,
+            frozenset(["A", "B"]): 3,
+            frozenset([]): 4,
+        }
+        total_sloc = 1 + 2 + 3 + 4
+
+        subset = {"A"}
+        used_sloc = 1 + 3
+        coverage_a = used_sloc / total_sloc * 100.0
+        self.assertEqual(average_coverage(setmap, subset), coverage_a)
+
+        subset = {"B"}
+        used_sloc = 2 + 3
+        coverage_b = used_sloc / total_sloc * 100.0
+        self.assertEqual(average_coverage(setmap, subset), coverage_b)
+
+        subset = {"A", "B"}
+        expected_avg = (coverage_a + coverage_b) / 2
+        self.assertEqual(average_coverage(setmap, subset), expected_avg)
+        self.assertEqual(average_coverage(setmap), expected_avg)
+
     def test_null_coverage(self):
         """Check coverage computation for null cases."""
         setmap = {
             frozenset(""): 0,
         }
         self.assertTrue(math.isnan(coverage(setmap)))
+        self.assertTrue(math.isnan(average_coverage(setmap)))
 
 
 if __name__ == "__main__":