ExtensionArray.Round method and tests

pandas/core/arrays/base.py

@@ -2342,6 +2342,9 @@ def _add_logical_ops(cls) -> None:
         setattr(cls, "__xor__", cls._create_logical_method(operator.xor))
         setattr(cls, "__rxor__", cls._create_logical_method(roperator.rxor))
 
+    def round(self, decimals: int = 0, *args, **kwargs) -> Self:
+        raise AbstractMethodError(self)
+
 
 class ExtensionScalarOpsMixin(ExtensionOpsMixin):
     """

pandas/tests/extension/base/__init__.py

@@ -53,6 +53,7 @@ class TestMyDtype(BaseDtypeTests):
     BaseArithmeticOpsTests,
     BaseComparisonOpsTests,
     BaseOpsUtil,
+    BaseRoundingTests,
     BaseUnaryOpsTests,
 )
 from pandas.tests.extension.base.printing import BasePrintingTests
@@ -86,6 +87,7 @@ class ExtensionTests(
     BaseArithmeticOpsTests,
     BaseComparisonOpsTests,
     BaseUnaryOpsTests,
+    BaseRoundingTests,
     BasePrintingTests,
     BaseReduceTests,
     BaseReshapingTests,

pandas/tests/extension/base/ops.py

@@ -263,3 +263,10 @@ def test_unary_ufunc_dunder_equivalence(self, data, ufunc):
         else:
             alt = ufunc(data)
             tm.assert_extension_array_equal(result, alt)
+
+
+class BaseRoundingTests:
+    def test_round(self, data):
+        result = pd.Series(data).round()
+        expected = pd.Series(np.round(data), dtype=data.dtype)
+        tm.assert_series_equal(result, expected)

pandas/tests/extension/decimal/test_decimal.py

@@ -226,6 +226,12 @@ def test_invert(self, data):
     @pytest.mark.parametrize("ufunc", [np.positive, np.negative, np.abs])
     def test_unary_ufunc_dunder_equivalence(self, data, ufunc):
         super().test_unary_ufunc_dunder_equivalence(data, ufunc)
+
+    @pytest.mark.xfail(
+        reason="DecimalArray.round is not implemented."
+    )
+    def test_round(self, data):
+        super().test_round(data)
 
 
 def test_take_na_value_other_decimal():

pandas/tests/extension/test_interval.py

@@ -95,6 +95,12 @@ def test_EA_types(self, engine, data):
     def test_invert(self, data):
         super().test_invert(data)
 
+    @pytest.mark.xfail(
+        reason="IntervalArray.round is not implemented."
+    )
+    def test_round(self, data):
+        super().test_round(data)
+
 
 # TODO: either belongs in tests.arrays.interval or move into base tests.
 def test_fillna_non_scalar_raises(data_missing):

pandas/tests/extension/test_masked.py

@@ -362,3 +362,11 @@ def test_invert(self, data, request):
 
 class Test2DCompat(base.Dim2CompatTests):
     pass
+
+
+class TestRounding(base.BaseRoundingTests):
+    def test_round(self, data, request):
+        if data.dtype == "boolean":
+            mark = pytest.mark.xfail(reason="Cannot round boolean dtype")
+            request.node.add_marker(mark)
+        super().test_round(data)