COMPAT: tzawareness behavior to be same as datetime

pandas/_libs/tslibs/c_timestamp.pyx

@@ -119,6 +119,10 @@ cdef class _Timestamp(datetime):
             else:
                 return NotImplemented
 
+
+        if op in [Py_EQ, Py_NE]:
+            return op == Py_NE
+
         self._assert_tzawareness_compat(other)
         return cmp_scalar(self.value, ots.value, op)
 
@@ -179,8 +183,7 @@ cdef class _Timestamp(datetime):
     cdef _assert_tzawareness_compat(_Timestamp self, datetime other):
         if self.tzinfo is None:
             if other.tzinfo is not None:
-                raise TypeError('Cannot compare tz-naive and tz-aware '
-                                'timestamps')
+                raise TypeError("Cannot compare tz-naive and tz-aware timestamps")
         elif other.tzinfo is None:
             raise TypeError('Cannot compare tz-naive and tz-aware timestamps')
 

pandas/tests/arithmetic/test_datetime64.py

@@ -526,7 +526,7 @@ def test_dti_cmp_nat_behaves_like_float_cmp_nan(self):
 
     @pytest.mark.parametrize(
         "op",
-        [operator.eq, operator.ne, operator.gt, operator.ge, operator.lt, operator.le],
+        [operator.gt, operator.ge, operator.lt, operator.le],
     )
     def test_comparison_tzawareness_compat(self, op, box_df_fail):
         # GH#18162

pandas/tests/scalar/timestamp/test_comparisons.py

@@ -85,10 +85,6 @@ def test_cant_compare_tz_naive_w_aware(self, utc_fixture):
         a = Timestamp("3/12/2012")
         b = Timestamp("3/12/2012", tz=utc_fixture)
 
-        with pytest.raises(TypeError):
-            a == b
-        with pytest.raises(TypeError):
-            a != b
         with pytest.raises(TypeError):
             a < b
         with pytest.raises(TypeError):
@@ -98,10 +94,6 @@ def test_cant_compare_tz_naive_w_aware(self, utc_fixture):
         with pytest.raises(TypeError):
             a >= b
 
-        with pytest.raises(TypeError):
-            b == a
-        with pytest.raises(TypeError):
-            b != a
         with pytest.raises(TypeError):
             b < a
         with pytest.raises(TypeError):
@@ -161,6 +153,20 @@ def test_compare_zerodim_array(self):
         result = arr > ts
         assert result is False
 
+    def test_timestamp_compare_tz(self):
+        # https://github.com/pandas-dev/pandas/issues/28507
+        ts = Timestamp.now()
+        ts2 = ts.tz_localize("UTC")
+
+        dt = ts.to_pydatetime()
+        dt2 = ts2.to_pydatetime()
+
+        assert ts != ts2
+        assert dt != dt2
+
+        assert not ts == ts2
+        assert not dt == dt2
+
 
 def test_rich_comparison_with_unsupported_type():
     # Comparisons with unsupported objects should return NotImplemented