fixed test case for cov

Author: jhendricks487

Diff for: pandas/tests/frame/methods/test_cov_corr.py

@@ -500,6 +500,10 @@ def test_corr_within_bounds(self):
 
     def test_cov_with_missing_values(self):
         df = DataFrame({"A": [1, 2, None, 4], "B": [2, 4, None, 9]})
-        expected = DataFrame({"A": [1.0, 1.0], "B": [1.0, 1.0]})
-        result = df.dropna().cov()
-        tm.assert_frame_equal(result, expected)
+        expected = DataFrame(
+            {"A": [2.333333, 5.500000], "B": [5.5, 13.0]}, index=["A", "B"]
+        )
+        result1 = df.cov()
+        result2 = df.dropna().cov()
+        tm.assert_frame_equal(result1, expected)
+        tm.assert_frame_equal(result2, expected)