Handle timedelta64

Author: Daniel Saxton

pandas/core/dtypes/cast.py

@@ -713,6 +713,8 @@ def astype_nansafe(arr, dtype, copy=True, skipna=False):
         if is_object_dtype(dtype):
             return tslibs.ints_to_pytimedelta(arr.view(np.int64))
         elif dtype == np.int64:
+            if isna(arr).any():
+                raise ValueError("Cannot convert NaT values to integer")
             return arr.view(dtype)
 
         if dtype not in [_INT64_DTYPE, _TD_DTYPE]:

pandas/tests/dtypes/test_common.py

@@ -709,8 +709,8 @@ def test__is_dtype_type(input_param, result):
     assert com._is_dtype_type(input_param, lambda tipo: tipo == result)
 
 
-@pytest.mark.parametrize("val", [np.datetime64("NaT")])
-@pytest.mark.parametrize("typ", [np.int8, np.int16, np.int32, np.int64])
+@pytest.mark.parametrize("val", [np.datetime64("NaT"), np.timedelta64("NaT")])
+@pytest.mark.parametrize("typ", [np.int64])
 def test_astype_nansafe(val, typ):
     arr = np.array([val])