#1269: fix a bug in pstats.add_callers() and add a unit test file for pstats.

Lib/test/test_pstats.py

@@ -0,0 +1,26 @@
+import unittest
+from test import test_support
+import pstats
+
+
+
+class AddCallersTestCase(unittest.TestCase):
+    """Tests for pstats.add_callers helper."""
+
+    def test_combine_results(self):
+        """pstats.add_callers should combine the call results of both target
+        and source by adding the call time. See issue1269."""
+        target = {"a": (1, 2, 3, 4)}
+        source = {"a": (1, 2, 3, 4), "b": (5, 6, 7, 8)}
+        new_callers = pstats.add_callers(target, source)
+        self.assertEqual(new_callers, {'a': (2, 4, 6, 8), 'b': (5, 6, 7, 8)})
+
+
+def test_main():
+    test_support.run_unittest(
+        AddCallersTestCase
+    )
+
+
+if __name__ == "__main__":
+    test_main()