Additional resample tests

Author: TomAugspurger

pandas/tests/test_resample.py

@@ -3368,6 +3368,34 @@ def test_aggregate_normal(self):
             assert_frame_equal(expected, dt_result)
         """
 
+    @pytest.mark.parametrize('method, unit', [
+        ('sum', 0),
+        ('prod', 1),
+    ])
+    def test_resample_entirly_nat_window(self, method, unit):
+        s = pd.Series([0] * 2 + [np.nan] * 2,
+                      index=pd.date_range('2017', periods=4))
+        # nan by default
+        result = methodcaller(method)(s.resample("2d"))
+        expected = pd.Series([0.0, np.nan],
+                             index=pd.to_datetime(['2017-01-01',
+                                                   '2017-01-03']))
+        tm.assert_series_equal(result, expected)
+
+        # min_count=0
+        result = methodcaller(method, min_count=0)(s.resample("2d"))
+        expected = pd.Series([0.0, unit],
+                             index=pd.to_datetime(['2017-01-01',
+                                                   '2017-01-03']))
+        tm.assert_series_equal(result, expected)
+
+        # min_count=1
+        result = methodcaller(method, min_count=1)(s.resample("2d"))
+        expected = pd.Series([0.0, np.nan],
+                             index=pd.to_datetime(['2017-01-01',
+                                                   '2017-01-03']))
+        tm.assert_series_equal(result, expected)
+
     def test_aggregate_with_nat(self):
         # check TimeGrouper's aggregation is identical as normal groupby