TST: assert no conversion to float when resampling datetime64 values (13119)

Author: jorisvandenbossche

pandas/tseries/tests/test_resample.py

@@ -1952,6 +1952,23 @@ def test_resample_timedelta_values(self):
         res = df['time'].resample('2D').first()
         tm.assert_series_equal(res, exp)
 
+    def test_resample_datetime_values(self):
+        # GH 13119
+        # check that datetime dtype is preserved when NaT values are
+        # introduced by the resampling
+
+        dates = [datetime(2016, 1, 15), datetime(2016, 1, 19)]
+        df = DataFrame({'timestamp': dates}, index=dates)
+
+        exp = Series([datetime(2016, 1, 15), pd.NaT, datetime(2016, 1, 19)],
+                     index=date_range('2016-01-15', periods=3, freq='2D'),
+                     name='timestamp')
+
+        res = df.resample('2D').first()['timestamp']
+        tm.assert_series_equal(res, exp)
+        res = df['timestamp'].resample('2D').first()
+        tm.assert_series_equal(res, exp)
+
 
 class TestPeriodIndex(Base, tm.TestCase):
     _multiprocess_can_split_ = True