TST: parametrize over dt64 unit

pandas/tests/arithmetic/test_datetime64.py

@@ -905,7 +905,7 @@ def test_dt64arr_add_sub_td64_nat(self, box_with_array, tz_naive_fixture):
 
         dti = date_range("1994-04-01", periods=9, tz=tz, freq="QS")
         other = np.timedelta64("NaT")
-        expected = DatetimeIndex(["NaT"] * 9, tz=tz)
+        expected = DatetimeIndex(["NaT"] * 9, tz=tz).as_unit("ns")
 
         obj = tm.box_expected(dti, box_with_array)
         expected = tm.box_expected(expected, box_with_array)
@@ -1590,13 +1590,13 @@ class TestDatetime64OverflowHandling:
 
     def test_dt64_overflow_masking(self, box_with_array):
         # GH#25317
-        left = Series([Timestamp("1969-12-31")])
+        left = Series([Timestamp("1969-12-31")], dtype="M8[ns]")
         right = Series([NaT])
 
         left = tm.box_expected(left, box_with_array)
         right = tm.box_expected(right, box_with_array)
 
-        expected = TimedeltaIndex([NaT])
+        expected = TimedeltaIndex([NaT], dtype="m8[ns]")
         expected = tm.box_expected(expected, box_with_array)
 
         result = left - right

pandas/tests/frame/indexing/test_setitem.py

@@ -1354,7 +1354,8 @@ def test_setitem_frame_dup_cols_dtype(self):
 
     def test_frame_setitem_empty_dataframe(self):
         # GH#28871
-        df = DataFrame({"date": [datetime(2000, 1, 1)]}).set_index("date")
+        dti = DatetimeIndex(["2000-01-01"], dtype="M8[ns]", name="date")
+        df = DataFrame({"date": dti}).set_index("date")
         df = df[0:0].copy()
 
         df["3010"] = None
@@ -1363,6 +1364,6 @@ def test_frame_setitem_empty_dataframe(self):
         expected = DataFrame(
             [],
             columns=["3010", "2010"],
-            index=Index([], dtype="datetime64[ns]", name="date"),
+            index=dti[:0],
         )
         tm.assert_frame_equal(df, expected)

pandas/tests/frame/methods/test_quantile.py

@@ -623,23 +623,23 @@ def test_quantile_nan(self, interp_method, request, using_array_manager):
         exp = DataFrame({"a": [3.0, 4.0], "b": [np.nan, np.nan]}, index=[0.5, 0.75])
         tm.assert_frame_equal(res, exp)
 
-    def test_quantile_nat(self, interp_method, request, using_array_manager):
+    def test_quantile_nat(self, interp_method, request, using_array_manager, unit):
         interpolation, method = interp_method
         if method == "table" and using_array_manager:
             request.applymarker(pytest.mark.xfail(reason="Axis name incorrectly set."))
         # full NaT column
-        df = DataFrame({"a": [pd.NaT, pd.NaT, pd.NaT]})
+        df = DataFrame({"a": [pd.NaT, pd.NaT, pd.NaT]}, dtype=f"M8[{unit}]")
 
         res = df.quantile(
             0.5, numeric_only=False, interpolation=interpolation, method=method
         )
-        exp = Series([pd.NaT], index=["a"], name=0.5)
+        exp = Series([pd.NaT], index=["a"], name=0.5, dtype=f"M8[{unit}]")
         tm.assert_series_equal(res, exp)
 
         res = df.quantile(
             [0.5], numeric_only=False, interpolation=interpolation, method=method
         )
-        exp = DataFrame({"a": [pd.NaT]}, index=[0.5])
+        exp = DataFrame({"a": [pd.NaT]}, index=[0.5], dtype=f"M8[{unit}]")
         tm.assert_frame_equal(res, exp)
 
         # mixed non-null / full null column
@@ -651,20 +651,29 @@ def test_quantile_nat(self, interp_method, request, using_array_manager):
                     Timestamp("2012-01-03"),
                 ],
                 "b": [pd.NaT, pd.NaT, pd.NaT],
-            }
+            },
+            dtype=f"M8[{unit}]",
         )
 
         res = df.quantile(
             0.5, numeric_only=False, interpolation=interpolation, method=method
         )
-        exp = Series([Timestamp("2012-01-02"), pd.NaT], index=["a", "b"], name=0.5)
+        exp = Series(
+            [Timestamp("2012-01-02"), pd.NaT],
+            index=["a", "b"],
+            name=0.5,
+            dtype=f"M8[{unit}]",
+        )
         tm.assert_series_equal(res, exp)
 
         res = df.quantile(
             [0.5], numeric_only=False, interpolation=interpolation, method=method
         )
         exp = DataFrame(
-            [[Timestamp("2012-01-02"), pd.NaT]], index=[0.5], columns=["a", "b"]
+            [[Timestamp("2012-01-02"), pd.NaT]],
+            index=[0.5],
+            columns=["a", "b"],
+            dtype=f"M8[{unit}]",
         )
         tm.assert_frame_equal(res, exp)
 

pandas/tests/frame/test_reductions.py

@@ -598,7 +598,7 @@ def test_sem(self, datetime_frame):
                     "C": [1.0],
                     "D": ["a"],
                     "E": Categorical(["a"], categories=["a"]),
-                    "F": to_datetime(["2000-1-2"]),
+                    "F": pd.DatetimeIndex(["2000-01-02"], dtype="M8[ns]"),
                     "G": to_timedelta(["1 days"]),
                 },
             ),
@@ -610,7 +610,7 @@ def test_sem(self, datetime_frame):
                     "C": [np.nan],
                     "D": np.array([np.nan], dtype=object),
                     "E": Categorical([np.nan], categories=["a"]),
-                    "F": [pd.NaT],
+                    "F": pd.DatetimeIndex([pd.NaT], dtype="M8[ns]"),
                     "G": to_timedelta([pd.NaT]),
                 },
             ),
@@ -621,7 +621,9 @@ def test_sem(self, datetime_frame):
                     "I": [8, 9, np.nan, np.nan],
                     "J": [1, np.nan, np.nan, np.nan],
                     "K": Categorical(["a", np.nan, np.nan, np.nan], categories=["a"]),
-                    "L": to_datetime(["2000-1-2", "NaT", "NaT", "NaT"]),
+                    "L": pd.DatetimeIndex(
+                        ["2000-01-02", "NaT", "NaT", "NaT"], dtype="M8[ns]"
+                    ),
                     "M": to_timedelta(["1 days", "nan", "nan", "nan"]),
                     "N": [0, 1, 2, 3],
                 },
@@ -633,7 +635,9 @@ def test_sem(self, datetime_frame):
                     "I": [8, 9, np.nan, np.nan],
                     "J": [1, np.nan, np.nan, np.nan],
                     "K": Categorical([np.nan, "a", np.nan, np.nan], categories=["a"]),
-                    "L": to_datetime(["NaT", "2000-1-2", "NaT", "NaT"]),
+                    "L": pd.DatetimeIndex(
+                        ["NaT", "2000-01-02", "NaT", "NaT"], dtype="M8[ns]"
+                    ),
                     "M": to_timedelta(["nan", "1 days", "nan", "nan"]),
                     "N": [0, 1, 2, 3],
                 },
@@ -648,13 +652,17 @@ def test_mode_dropna(self, dropna, expected):
                 "C": [1, np.nan, np.nan, np.nan],
                 "D": [np.nan, np.nan, "a", np.nan],
                 "E": Categorical([np.nan, np.nan, "a", np.nan]),
-                "F": to_datetime(["NaT", "2000-1-2", "NaT", "NaT"]),
+                "F": pd.DatetimeIndex(
+                    ["NaT", "2000-01-02", "NaT", "NaT"], dtype="M8[ns]"
+                ),
                 "G": to_timedelta(["1 days", "nan", "nan", "nan"]),
                 "H": [8, 8, 9, 9],
                 "I": [9, 9, 8, 8],
                 "J": [1, 1, np.nan, np.nan],
                 "K": Categorical(["a", np.nan, "a", np.nan]),
-                "L": to_datetime(["2000-1-2", "2000-1-2", "NaT", "NaT"]),
+                "L": pd.DatetimeIndex(
+                    ["2000-01-02", "2000-01-02", "NaT", "NaT"], dtype="M8[ns]"
+                ),
                 "M": to_timedelta(["1 days", "nan", "1 days", "nan"]),
                 "N": np.arange(4, dtype="int64"),
             }

pandas/tests/groupby/methods/test_groupby_shift_diff.py

@@ -117,10 +117,11 @@ def test_group_diff_real_frame(any_real_numpy_dtype):
         [Timedelta("5 days"), Timedelta("6 days"), Timedelta("7 days")],
     ],
 )
-def test_group_diff_datetimelike(data):
+def test_group_diff_datetimelike(data, unit):
     df = DataFrame({"a": [1, 2, 2], "b": data})
+    df["b"] = df["b"].dt.as_unit(unit)
     result = df.groupby("a")["b"].diff()
-    expected = Series([NaT, NaT, Timedelta("1 days")], name="b")
+    expected = Series([NaT, NaT, Timedelta("1 days")], name="b").dt.as_unit(unit)
     tm.assert_series_equal(result, expected)
 
 

pandas/tests/groupby/test_timegrouper.py

@@ -98,11 +98,17 @@ def test_groupby_with_timegrouper(self):
         for df in [df_original, df_reordered]:
             df = df.set_index(["Date"])
 
+            exp_dti = date_range(
+                "20130901",
+                "20131205",
+                freq="5D",
+                name="Date",
+                inclusive="left",
+                unit=df.index.unit,
+            )
             expected = DataFrame(
                 {"Buyer": 0, "Quantity": 0},
-                index=date_range(
-                    "20130901", "20131205", freq="5D", name="Date", inclusive="left"
-                ),
+                index=exp_dti,
             )
             # Cast to object to avoid implicit cast when setting entry to "CarlCarlCarl"
             expected = expected.astype({"Buyer": object})
@@ -514,6 +520,7 @@ def test_groupby_groups_datetimeindex(self):
         groups = grouped.groups
         assert isinstance(next(iter(groups.keys())), datetime)
 
+    def test_groupby_groups_datetimeindex2(self):
         # GH#11442
         index = date_range("2015/01/01", periods=5, name="date")
         df = DataFrame({"A": [5, 6, 7, 8, 9], "B": [1, 2, 3, 4, 5]}, index=index)
@@ -876,7 +883,9 @@ def test_groupby_apply_timegrouper_with_nat_dict_returns(
 
         res = gb["Quantity"].apply(lambda x: {"foo": len(x)})
 
-        dti = date_range("2013-09-01", "2013-10-01", freq="5D", name="Date")
+        df = gb.obj
+        unit = df["Date"]._values.unit
+        dti = date_range("2013-09-01", "2013-10-01", freq="5D", name="Date", unit=unit)
         mi = MultiIndex.from_arrays([dti, ["foo"] * len(dti)])
         expected = Series([3, 0, 0, 0, 0, 0, 2], index=mi, name="Quantity")
         tm.assert_series_equal(res, expected)
@@ -890,7 +899,9 @@ def test_groupby_apply_timegrouper_with_nat_scalar_returns(
 
         res = gb["Quantity"].apply(lambda x: x.iloc[0] if len(x) else np.nan)
 
-        dti = date_range("2013-09-01", "2013-10-01", freq="5D", name="Date")
+        df = gb.obj
+        unit = df["Date"]._values.unit
+        dti = date_range("2013-09-01", "2013-10-01", freq="5D", name="Date", unit=unit)
         expected = Series(
             [18, np.nan, np.nan, np.nan, np.nan, np.nan, 5],
             index=dti._with_freq(None),
@@ -919,9 +930,10 @@ def test_groupby_apply_timegrouper_with_nat_apply_squeeze(
         with tm.assert_produces_warning(FutureWarning, match=msg):
             res = gb.apply(lambda x: x["Quantity"] * 2)
 
+        dti = Index([Timestamp("2013-12-31")], dtype=df["Date"].dtype, name="Date")
         expected = DataFrame(
             [[36, 6, 6, 10, 2]],
-            index=Index([Timestamp("2013-12-31")], name="Date"),
+            index=dti,
             columns=Index([0, 1, 5, 2, 3], name="Quantity"),
         )
         tm.assert_frame_equal(res, expected)

pandas/tests/groupby/transform/test_transform.py

@@ -115,12 +115,15 @@ def test_transform_fast2():
     )
     result = df.groupby("grouping").transform("first")
 
-    dates = [
-        Timestamp("2014-1-1"),
-        Timestamp("2014-1-2"),
-        Timestamp("2014-1-2"),
-        Timestamp("2014-1-4"),
-    ]
+    dates = pd.Index(
+        [
+            Timestamp("2014-1-1"),
+            Timestamp("2014-1-2"),
+            Timestamp("2014-1-2"),
+            Timestamp("2014-1-4"),
+        ],
+        dtype="M8[ns]",
+    )
     expected = DataFrame(
         {"f": [1.1, 2.1, 2.1, 4.5], "d": dates, "i": [1, 2, 2, 4]},
         columns=["f", "i", "d"],
@@ -532,7 +535,7 @@ def test_series_fast_transform_date():
         Timestamp("2014-1-2"),
         Timestamp("2014-1-4"),
     ]
-    expected = Series(dates, name="d")
+    expected = Series(dates, name="d", dtype="M8[ns]")
     tm.assert_series_equal(result, expected)
 
 
@@ -1204,7 +1207,9 @@ def test_groupby_transform_with_datetimes(func, values):
 
     result = stocks.groupby(stocks["week_id"])["price"].transform(func)
 
-    expected = Series(data=pd.to_datetime(values), index=dates, name="price")
+    expected = Series(
+        data=pd.to_datetime(values).as_unit("ns"), index=dates, name="price"
+    )
 
     tm.assert_series_equal(result, expected)
 

pandas/tests/indexes/datetimes/methods/test_astype.py

@@ -292,7 +292,7 @@ def test_integer_index_astype_datetime(self, tz, dtype):
         # GH 20997, 20964, 24559
         val = [Timestamp("2018-01-01", tz=tz).as_unit("ns")._value]
         result = Index(val, name="idx").astype(dtype)
-        expected = DatetimeIndex(["2018-01-01"], tz=tz, name="idx")
+        expected = DatetimeIndex(["2018-01-01"], tz=tz, name="idx").as_unit("ns")
         tm.assert_index_equal(result, expected)
 
     def test_dti_astype_period(self):
@@ -312,8 +312,9 @@ class TestAstype:
     def test_astype_category(self, tz):
         obj = date_range("2000", periods=2, tz=tz, name="idx")
         result = obj.astype("category")
+        dti = DatetimeIndex(["2000-01-01", "2000-01-02"], tz=tz).as_unit("ns")
         expected = pd.CategoricalIndex(
-            [Timestamp("2000-01-01", tz=tz), Timestamp("2000-01-02", tz=tz)],
+            dti,
             name="idx",
         )
         tm.assert_index_equal(result, expected)