add assertion on type of df.values being numpy.ndarray + dtype='O' except for datetime64[ns]

Author: sdementen

pandas/tests/frame/test_dtypes.py

@@ -635,16 +635,19 @@ def test_values_with_tz_dtypes(self):
             ["B", "B"],
         ]:
             df_sub = df[col]
+            arr = df_sub.values
 
+            self.assert(type(arr)==numpy.ndarray)
+            
             # array has the same dtype as dataframe only and only if
-            # - dataframe has a single column
-            # - or all columns are of type datetime64[ns]
+            # - all columns are of type datetime64[ns]
 
             # TODO: replace 2nd condition by 'all columns are of type datetime64[ns,same timezone]'
             # i.e. the test should succeed when replacing the condition be `if len(set(df_sub.dtypes.values))==1:`
-            if len(df_sub.dtypes) == 1 or all(df_sub.dtypes.values=="<M8[ns]"):
-                self.assertTrue(df_sub.values.dtype == df_sub.dtypes.values[0])
+            # too complex before 2.0 as DatetimeTZBlock is single column
+            if all(df_sub.dtypes.values=="<M8[ns]"):
+                self.assertTrue(arr.dtype == df_sub.dtypes.values[0])
 
             # otherwise, dtype is object
             else:
-                self.assertTrue(df_sub.values.dtype == object)
+                self.assertTrue(arr.dtype == object)