Updated tests according to feedback

Author: arthurlw

pandas/tests/io/parser/dtypes/test_categorical.py

@@ -272,15 +272,46 @@ def test_categorical_coerces_numeric(all_parsers):
     tm.assert_frame_equal(result, expected)
 
 
+def test_categorical_coerces_datetime(all_parsers):
+    parser = all_parsers
+    dti = pd.DatetimeIndex(["2017-01-01", "2018-01-01", "2019-01-01"], freq=None)
+
+    dtype = {"b": CategoricalDtype(dti)}
+
+    data = "b\n2017-01-01\n2018-01-01\n2019-01-01"
+    expected = DataFrame({"b": Categorical(dtype["b"].categories)})
+
+    if parser.engine == "pyarrow":
+        msg = "Constructing a Categorical with a dtype and values containing"
+        with tm.assert_produces_warning(
+            Pandas4Warning, match=msg, check_stacklevel=False
+        ):
+            result = parser.read_csv(StringIO(data), dtype=dtype)
+        tm.assert_series_equal(
+            result["b"].isna(), pd.Series([True, True, True], name="b")
+        )
+    else:
+        result = parser.read_csv(StringIO(data), dtype=dtype)
+        tm.assert_frame_equal(result, expected)
+
+
 def test_categorical_coerces_timestamp(all_parsers):
     parser = all_parsers
-    dtype = {"b": CategoricalDtype([Timestamp("2014-01-01 12:00:00")])}
+    dtype = {"b": CategoricalDtype([Timestamp("2014")])}
 
-    data = "b\n2014-01-01 12:00:00\n2014-01-01 12:00:00"
-    expected = DataFrame({"b": Categorical([Timestamp("2014-01-01 12:00:00")] * 2)})
+    data = "b\n2014-01-01\n2014-01-01"
+    expected = DataFrame({"b": Categorical([Timestamp("2014")] * 2)})
 
-    result = parser.read_csv(StringIO(data), dtype=dtype)
-    tm.assert_frame_equal(result, expected)
+    if parser.engine == "pyarrow":
+        msg = "Constructing a Categorical with a dtype and values containing"
+        with tm.assert_produces_warning(
+            Pandas4Warning, match=msg, check_stacklevel=False
+        ):
+            result = parser.read_csv(StringIO(data), dtype=dtype)
+        tm.assert_series_equal(result["b"].isna(), pd.Series([True, True], name="b"))
+    else:
+        result = parser.read_csv(StringIO(data), dtype=dtype)
+        tm.assert_frame_equal(result, expected)
 
 
 def test_categorical_coerces_timedelta(all_parsers):

pandas/tests/series/test_arithmetic.py

@@ -757,19 +757,22 @@ def test_datetime_understood(self, unit):
         expected = Series(exp_dti)
         tm.assert_series_equal(result, expected)
 
-    def test_align_date_objects_with_datetimeindex_coerced(self):
+    def test_align_date_objects_with_datetimeindex(self):
         # GH#62158: datetime.date objects no longer auto-align with Timestamps
         rng = date_range("1/1/2000", periods=20)
         ts = Series(np.random.default_rng(2).standard_normal(20), index=rng)
 
         ts_slice = ts[5:]
         ts2 = ts_slice.copy()
-        ts2.index = pd.to_datetime([x.date() for x in ts2.index])
+        ts2.index = [x.date() for x in ts2.index]
 
         result = ts + ts2
-        expected = ts + ts[5:]
-        expected.index = expected.index._with_freq(None)
+        result2 = ts2 + ts
+        expected = Series(dtype=float, index=result.index)
+        expected2 = Series(dtype=float, index=result2.index)
+
         tm.assert_series_equal(result, expected)
+        tm.assert_series_equal(result2, expected2)
 
 
 class TestNamePreservation: