done

lib/python3.11/site-packages/pandas/tests/extension/base/reduce.py

@@ -0,0 +1,153 @@
+from typing import final
+
+import pytest
+
+import pandas as pd
+import pandas._testing as tm
+from pandas.api.types import is_numeric_dtype
+
+
+class BaseReduceTests:
+    """
+    Reduction specific tests. Generally these only
+    make sense for numeric/boolean operations.
+    """
+
+    def _supports_reduction(self, ser: pd.Series, op_name: str) -> bool:
+        # Specify if we expect this reduction to succeed.
+        return False
+
+    def check_reduce(self, ser: pd.Series, op_name: str, skipna: bool):
+        # We perform the same operation on the np.float64 data and check
+        #  that the results match. Override if you need to cast to something
+        #  other than float64.
+        res_op = getattr(ser, op_name)
+
+        try:
+            alt = ser.astype("float64")
+        except (TypeError, ValueError):
+            # e.g. Interval can't cast (TypeError), StringArray can't cast
+            #  (ValueError), so let's cast to object and do
+            #  the reduction pointwise
+            alt = ser.astype(object)
+
+        exp_op = getattr(alt, op_name)
+        if op_name == "count":
+            result = res_op()
+            expected = exp_op()
+        else:
+            result = res_op(skipna=skipna)
+            expected = exp_op(skipna=skipna)
+        tm.assert_almost_equal(result, expected)
+
+    def _get_expected_reduction_dtype(self, arr, op_name: str, skipna: bool):
+        # Find the expected dtype when the given reduction is done on a DataFrame
+        # column with this array.  The default assumes float64-like behavior,
+        # i.e. retains the dtype.
+        return arr.dtype
+
+    # We anticipate that authors should not need to override check_reduce_frame,
+    #  but should be able to do any necessary overriding in
+    #  _get_expected_reduction_dtype. If you have a use case where this
+    #  does not hold, please let us know at github.com/pandas-dev/pandas/issues.
+    @final
+    def check_reduce_frame(self, ser: pd.Series, op_name: str, skipna: bool):
+        # Check that the 2D reduction done in a DataFrame reduction "looks like"
+        # a wrapped version of the 1D reduction done by Series.
+        arr = ser.array
+        df = pd.DataFrame({"a": arr})
+
+        kwargs = {"ddof": 1} if op_name in ["var", "std"] else {}
+
+        cmp_dtype = self._get_expected_reduction_dtype(arr, op_name, skipna)
+
+        # The DataFrame method just calls arr._reduce with keepdims=True,
+        #  so this first check is perfunctory.
+        result1 = arr._reduce(op_name, skipna=skipna, keepdims=True, **kwargs)
+        result2 = getattr(df, op_name)(skipna=skipna, **kwargs).array
+        tm.assert_extension_array_equal(result1, result2)
+
+        # Check that the 2D reduction looks like a wrapped version of the
+        #  1D reduction
+        if not skipna and ser.isna().any():
+            expected = pd.array([pd.NA], dtype=cmp_dtype)
+        else:
+            exp_value = getattr(ser.dropna(), op_name)()
+            expected = pd.array([exp_value], dtype=cmp_dtype)
+
+        tm.assert_extension_array_equal(result1, expected)
+
+    @pytest.mark.parametrize("skipna", [True, False])
+    def test_reduce_series_boolean(self, data, all_boolean_reductions, skipna):
+        op_name = all_boolean_reductions
+        ser = pd.Series(data)
+
+        if not self._supports_reduction(ser, op_name):
+            # TODO: the message being checked here isn't actually checking anything
+            msg = (
+                "[Cc]annot perform|Categorical is not ordered for operation|"
+                "does not support reduction|"
+            )
+
+            with pytest.raises(TypeError, match=msg):
+                getattr(ser, op_name)(skipna=skipna)
+
+        else:
+            self.check_reduce(ser, op_name, skipna)
+
+    @pytest.mark.filterwarnings("ignore::RuntimeWarning")
+    @pytest.mark.parametrize("skipna", [True, False])
+    def test_reduce_series_numeric(self, data, all_numeric_reductions, skipna):
+        op_name = all_numeric_reductions
+        ser = pd.Series(data)
+
+        if not self._supports_reduction(ser, op_name):
+            # TODO: the message being checked here isn't actually checking anything
+            msg = (
+                "[Cc]annot perform|Categorical is not ordered for operation|"
+                "does not support reduction|"
+            )
+
+            with pytest.raises(TypeError, match=msg):
+                getattr(ser, op_name)(skipna=skipna)
+
+        else:
+            # min/max with empty produce numpy warnings
+            self.check_reduce(ser, op_name, skipna)
+
+    @pytest.mark.parametrize("skipna", [True, False])
+    def test_reduce_frame(self, data, all_numeric_reductions, skipna):
+        op_name = all_numeric_reductions
+        ser = pd.Series(data)
+        if not is_numeric_dtype(ser.dtype):
+            pytest.skip(f"{ser.dtype} is not numeric dtype")
+
+        if op_name in ["count", "kurt", "sem"]:
+            pytest.skip(f"{op_name} not an array method")
+
+        if not self._supports_reduction(ser, op_name):
+            pytest.skip(f"Reduction {op_name} not supported for this dtype")
+
+        self.check_reduce_frame(ser, op_name, skipna)
+
+
+# TODO(3.0): remove BaseNoReduceTests, BaseNumericReduceTests,
+#  BaseBooleanReduceTests
+class BaseNoReduceTests(BaseReduceTests):
+    """we don't define any reductions"""
+
+
+class BaseNumericReduceTests(BaseReduceTests):
+    # For backward compatibility only, this only runs the numeric reductions
+    def _supports_reduction(self, ser: pd.Series, op_name: str) -> bool:
+        if op_name in ["any", "all"]:
+            pytest.skip("These are tested in BaseBooleanReduceTests")
+        return True
+
+
+class BaseBooleanReduceTests(BaseReduceTests):
+    # For backward compatibility only, this only runs the numeric reductions
+    def _supports_reduction(self, ser: pd.Series, op_name: str) -> bool:
+        if op_name not in ["any", "all"]:
+            pytest.skip("These are tested in BaseNumericReduceTests")
+        return True