REF: update to use extension test patterns (#54436)

Author: jbrockmendel

pandas/tests/extension/base/reduce.py

@@ -23,7 +23,15 @@ def check_reduce(self, s, op_name, skipna):
         #  that the results match. Override if you need to cast to something
         #  other than float64.
         res_op = getattr(s, op_name)
-        exp_op = getattr(s.astype("float64"), op_name)
+
+        try:
+            alt = s.astype("float64")
+        except TypeError:
+            # e.g. Interval can't cast, so let's cast to object and do
+            #  the reduction pointwise
+            alt = s.astype(object)
+
+        exp_op = getattr(alt, op_name)
         if op_name == "count":
             result = res_op()
             expected = exp_op()

pandas/tests/extension/decimal/test_decimal.py

@@ -152,14 +152,8 @@ def _supports_reduction(self, obj, op_name: str) -> bool:
         return True
 
     def check_reduce(self, s, op_name, skipna):
-        if op_name in ["median", "skew", "kurt", "sem"]:
-            msg = r"decimal does not support the .* operation"
-            with pytest.raises(NotImplementedError, match=msg):
-                getattr(s, op_name)(skipna=skipna)
-        elif op_name == "count":
-            result = getattr(s, op_name)()
-            expected = len(s) - s.isna().sum()
-            tm.assert_almost_equal(result, expected)
+        if op_name == "count":
+            return super().check_reduce(s, op_name, skipna)
         else:
             result = getattr(s, op_name)(skipna=skipna)
             expected = getattr(np.asarray(s), op_name)()
@@ -189,12 +183,17 @@ def _reduce(self, name: str, *, skipna: bool = True, **kwargs):
 
 
 class TestReduce(Reduce, base.BaseReduceTests):
-    @pytest.mark.parametrize("skipna", [True, False])
-    def test_reduce_frame(self, data, all_numeric_reductions, skipna):
+    def test_reduce_series_numeric(self, data, all_numeric_reductions, skipna, request):
+        if all_numeric_reductions in ["kurt", "skew", "sem", "median"]:
+            mark = pytest.mark.xfail(raises=NotImplementedError)
+            request.node.add_marker(mark)
+        super().test_reduce_series_numeric(data, all_numeric_reductions, skipna)
+
+    def test_reduce_frame(self, data, all_numeric_reductions, skipna, request):
         op_name = all_numeric_reductions
         if op_name in ["skew", "median"]:
-            assert not hasattr(data, op_name)
-            pytest.skip(f"{op_name} not an array method")
+            mark = pytest.mark.xfail(raises=NotImplementedError)
+            request.node.add_marker(mark)
 
         return super().test_reduce_frame(data, all_numeric_reductions, skipna)
 

pandas/tests/extension/test_interval.py

@@ -18,10 +18,7 @@
 
 from pandas.core.dtypes.dtypes import IntervalDtype
 
-from pandas import (
-    Interval,
-    Series,
-)
+from pandas import Interval
 from pandas.core.arrays import IntervalArray
 from pandas.tests.extension import base
 
@@ -106,18 +103,8 @@ class TestInterface(BaseInterval, base.BaseInterfaceTests):
 
 
 class TestReduce(base.BaseReduceTests):
-    @pytest.mark.parametrize("skipna", [True, False])
-    def test_reduce_series_numeric(self, data, all_numeric_reductions, skipna):
-        op_name = all_numeric_reductions
-        ser = Series(data)
-
-        if op_name in ["min", "max"]:
-            # IntervalArray *does* implement these
-            assert getattr(ser, op_name)(skipna=skipna) in data
-            assert getattr(data, op_name)(skipna=skipna) in data
-            return
-
-        super().test_reduce_series_numeric(data, all_numeric_reductions, skipna)
+    def _supports_reduction(self, obj, op_name: str) -> bool:
+        return op_name in ["min", "max"]
 
 
 class TestMethods(BaseInterval, base.BaseMethodsTests):
@@ -145,9 +132,7 @@ class TestSetitem(BaseInterval, base.BaseSetitemTests):
 
 
 class TestPrinting(BaseInterval, base.BasePrintingTests):
-    @pytest.mark.xfail(reason="Interval has custom repr")
-    def test_array_repr(self, data, size):
-        super().test_array_repr()
+    pass
 
 
 class TestParsing(BaseInterval, base.BaseParsingTests):