TST/REF: share Series setitem tests

pandas/tests/series/indexing/test_indexing.py

@@ -542,56 +542,6 @@ def test_setitem_td64_non_nano():
     tm.assert_series_equal(ser, expected)
 
 
-@pytest.mark.parametrize(
-    "nat_val",
-    [
-        pd.NaT,
-        np.timedelta64("NaT", "ns"),
-        np.datetime64("NaT", "ns"),
-    ],
-)
-@pytest.mark.parametrize("tz", [None, "UTC"])
-def test_dt64_series_assign_nat(nat_val, tz, indexer_sli):
-    # some nat-like values should be cast to datetime64 when inserting
-    #  into a datetime64 series.  Others should coerce to object
-    #  and retain their dtypes.
-    dti = pd.date_range("2016-01-01", periods=3, tz=tz)
-    base = Series(dti)
-    expected = Series([pd.NaT] + list(dti[1:]), dtype=dti.dtype)
-
-    should_cast = nat_val is pd.NaT or base.dtype == nat_val.dtype
-    if not should_cast:
-        expected = expected.astype(object)
-
-    ser = base.copy(deep=True)
-    indexer_sli(ser)[0] = nat_val
-    tm.assert_series_equal(ser, expected)
-
-
-@pytest.mark.parametrize(
-    "nat_val",
-    [
-        pd.NaT,
-        np.timedelta64("NaT", "ns"),
-        np.datetime64("NaT", "ns"),
-    ],
-)
-def test_td64_series_assign_nat(nat_val, indexer_sli):
-    # some nat-like values should be cast to timedelta64 when inserting
-    #  into a timedelta64 series.  Others should coerce to object
-    #  and retain their dtypes.
-    base = Series([0, 1, 2], dtype="m8[ns]")
-    expected = Series([pd.NaT, 1, 2], dtype="m8[ns]")
-
-    should_cast = nat_val is pd.NaT or base.dtype == nat_val.dtype
-    if not should_cast:
-        expected = expected.astype(object)
-
-    ser = base.copy(deep=True)
-    indexer_sli(ser)[0] = nat_val
-    tm.assert_series_equal(ser, expected)
-
-
 def test_underlying_data_conversion():
     # GH 4080
     df = DataFrame({c: [1, 2, 3] for c in ["a", "b", "c"]})

pandas/tests/series/indexing/test_setitem.py

@@ -167,15 +167,6 @@ def test_setitem_boolean_python_list(self, func):
         expected = Series(["a", "b", "c"])
         tm.assert_series_equal(ser, expected)
 
-    @pytest.mark.parametrize("value", [None, NaT, np.nan])
-    def test_setitem_boolean_td64_values_cast_na(self, value):
-        # GH#18586
-        series = Series([0, 1, 2], dtype="timedelta64[ns]")
-        mask = series == series[0]
-        series[mask] = value
-        expected = Series([NaT, 1, 2], dtype="timedelta64[ns]")
-        tm.assert_series_equal(series, expected)
-
     def test_setitem_boolean_nullable_int_types(self, any_nullable_numeric_dtype):
         # GH: 26468
         ser = Series([5, 6, 7, 8], dtype=any_nullable_numeric_dtype)
@@ -640,62 +631,43 @@ def is_inplace(self):
         return True
 
 
-class TestSetitemNATimedelta64Dtype(SetitemCastingEquivalents):
-    # some nat-like values should be cast to timedelta64 when inserting
-    #  into a timedelta64 series.  Others should coerce to object
-    #  and retain their dtypes.
-
-    @pytest.fixture
-    def obj(self):
-        return Series([0, 1, 2], dtype="m8[ns]")
+class TestSetitemNADatetimeLikeDtype(SetitemCastingEquivalents):
+    # some nat-like values should be cast to datetime64/timedelta64 when
+    #  inserting into a datetime64/timedelta64 series.  Others should coerce
+    #  to object and retain their dtypes.
+    # GH#18586 for td64 and boolean mask case
 
     @pytest.fixture(
-        params=[NaT, np.timedelta64("NaT", "ns"), np.datetime64("NaT", "ns")]
+        params=["m8[ns]", "M8[ns]", "datetime64[ns, UTC]", "datetime64[ns, US/Central]"]
     )
-    def val(self, request):
+    def dtype(self, request):
         return request.param
 
     @pytest.fixture
-    def is_inplace(self, val):
-        # cast to object iff val is datetime64("NaT")
-        return val is NaT or val.dtype.kind == "m"
-
-    @pytest.fixture
-    def expected(self, obj, val, is_inplace):
-        dtype = obj.dtype if is_inplace else object
-        expected = Series([val] + list(obj[1:]), dtype=dtype)
-        return expected
-
-    @pytest.fixture
-    def key(self):
-        return 0
-
-
-class TestSetitemNADatetime64Dtype(SetitemCastingEquivalents):
-    # some nat-like values should be cast to datetime64 when inserting
-    #  into a datetime64 series.  Others should coerce to object
-    #  and retain their dtypes.
-
-    @pytest.fixture(params=[None, "UTC", "US/Central"])
-    def obj(self, request):
-        tz = request.param
-        dti = date_range("2016-01-01", periods=3, tz=tz)
-        return Series(dti)
+    def obj(self, dtype):
+        i8vals = date_range("2016-01-01", periods=3).asi8
+        idx = Index(i8vals, dtype=dtype)
+        assert idx.dtype == dtype
+        return Series(idx)
 
     @pytest.fixture(
-        params=[NaT, np.timedelta64("NaT", "ns"), np.datetime64("NaT", "ns")]
+        params=[
+            None,
+            np.nan,
+            NaT,
+            np.timedelta64("NaT", "ns"),
+            np.datetime64("NaT", "ns"),
+        ]
     )
     def val(self, request):
         return request.param
 
     @pytest.fixture
     def is_inplace(self, val, obj):
-        if obj._values.tz is None:
-            # cast to object iff val is timedelta64("NaT")
-            return val is NaT or val.dtype.kind == "M"
-
-        # otherwise we have to exclude tznaive dt64("NaT")
-        return val is NaT
+        # td64   -> cast to object iff val is datetime64("NaT")
+        # dt64   -> cast to object iff val is timedelta64("NaT")
+        # dt64tz -> cast to object with anything _but_ NaT
+        return val is NaT or val is None or val is np.nan or obj.dtype == val.dtype
 
     @pytest.fixture
     def expected(self, obj, val, is_inplace):