TST: use one-class pattern in test_numpy (#56512)

* TST: use one-class pattern in test_numpy

* revert accidentally-commited

Author: jbrockmendel

pandas/tests/extension/base/interface.py

@@ -1,6 +1,7 @@
 import numpy as np
 import pytest
 
+from pandas.core.dtypes.cast import construct_1d_object_array_from_listlike
 from pandas.core.dtypes.common import is_extension_array_dtype
 from pandas.core.dtypes.dtypes import ExtensionDtype
 
@@ -65,6 +66,9 @@ def test_array_interface(self, data):
 
         result = np.array(data, dtype=object)
         expected = np.array(list(data), dtype=object)
+        if expected.ndim > 1:
+            # nested data, explicitly construct as 1D
+            expected = construct_1d_object_array_from_listlike(list(data))
         tm.assert_numpy_array_equal(result, expected)
 
     def test_is_extension_array_dtype(self, data):

pandas/tests/extension/test_numpy.py

@@ -18,23 +18,14 @@
 import numpy as np
 import pytest
 
-from pandas.core.dtypes.cast import can_hold_element
 from pandas.core.dtypes.dtypes import NumpyEADtype
 
 import pandas as pd
 import pandas._testing as tm
 from pandas.api.types import is_object_dtype
 from pandas.core.arrays.numpy_ import NumpyExtensionArray
-from pandas.core.internals import blocks
 from pandas.tests.extension import base
 
-
-def _can_hold_element_patched(obj, element) -> bool:
-    if isinstance(element, NumpyExtensionArray):
-        element = element.to_numpy()
-    return can_hold_element(obj, element)
-
-
 orig_assert_attr_equal = tm.assert_attr_equal
 
 
@@ -78,7 +69,6 @@ def allow_in_pandas(monkeypatch):
     """
     with monkeypatch.context() as m:
         m.setattr(NumpyExtensionArray, "_typ", "extension")
-        m.setattr(blocks, "can_hold_element", _can_hold_element_patched)
         m.setattr(tm.asserters, "assert_attr_equal", _assert_attr_equal)
         yield
 
@@ -175,15 +165,7 @@ def skip_numpy_object(dtype, request):
 skip_nested = pytest.mark.usefixtures("skip_numpy_object")
 
 
-class BaseNumPyTests:
-    pass
-
-
-class TestCasting(BaseNumPyTests, base.BaseCastingTests):
-    pass
-
-
-class TestConstructors(BaseNumPyTests, base.BaseConstructorsTests):
+class TestNumpyExtensionArray(base.ExtensionTests):
     @pytest.mark.skip(reason="We don't register our dtype")
     # We don't want to register. This test should probably be split in two.
     def test_from_dtype(self, data):
@@ -194,8 +176,6 @@ def test_series_constructor_scalar_with_index(self, data, dtype):
         # ValueError: Length of passed values is 1, index implies 3.
         super().test_series_constructor_scalar_with_index(data, dtype)
 
-
-class TestDtype(BaseNumPyTests, base.BaseDtypeTests):
     def test_check_dtype(self, data, request, using_infer_string):
         if data.dtype.numpy_dtype == "object":
             request.applymarker(
@@ -214,26 +194,11 @@ def test_is_not_object_type(self, dtype, request):
         else:
             super().test_is_not_object_type(dtype)
 
-
-class TestGetitem(BaseNumPyTests, base.BaseGetitemTests):
     @skip_nested
     def test_getitem_scalar(self, data):
         # AssertionError
         super().test_getitem_scalar(data)
 
-
-class TestGroupby(BaseNumPyTests, base.BaseGroupbyTests):
-    pass
-
-
-class TestInterface(BaseNumPyTests, base.BaseInterfaceTests):
-    @skip_nested
-    def test_array_interface(self, data):
-        # NumPy array shape inference
-        super().test_array_interface(data)
-
-
-class TestMethods(BaseNumPyTests, base.BaseMethodsTests):
     @skip_nested
     def test_shift_fill_value(self, data):
         # np.array shape inference. Shift implementation fails.
@@ -251,7 +216,9 @@ def test_fillna_copy_series(self, data_missing):
 
     @skip_nested
     def test_searchsorted(self, data_for_sorting, as_series):
-        # Test setup fails.
+        # TODO: NumpyExtensionArray.searchsorted calls ndarray.searchsorted which
+        #  isn't quite what we want in nested data cases. Instead we need to
+        #  adapt something like libindex._bin_search.
         super().test_searchsorted(data_for_sorting, as_series)
 
     @pytest.mark.xfail(reason="NumpyExtensionArray.diff may fail on dtype")
@@ -270,38 +237,60 @@ def test_insert_invalid(self, data, invalid_scalar):
         # NumpyExtensionArray[object] can hold anything, so skip
         super().test_insert_invalid(data, invalid_scalar)
 
-
-class TestArithmetics(BaseNumPyTests, base.BaseArithmeticOpsTests):
     divmod_exc = None
     series_scalar_exc = None
     frame_scalar_exc = None
     series_array_exc = None
 
-    @skip_nested
     def test_divmod(self, data):
+        divmod_exc = None
+        if data.dtype.kind == "O":
+            divmod_exc = TypeError
+        self.divmod_exc = divmod_exc
         super().test_divmod(data)
 
-    @skip_nested
-    def test_arith_series_with_scalar(self, data, all_arithmetic_operators):
+    def test_divmod_series_array(self, data):
+        ser = pd.Series(data)
+        exc = None
+        if data.dtype.kind == "O":
+            exc = TypeError
+            self.divmod_exc = exc
+        self._check_divmod_op(ser, divmod, data)
+
+    def test_arith_series_with_scalar(self, data, all_arithmetic_operators, request):
+        opname = all_arithmetic_operators
+        series_scalar_exc = None
+        if data.dtype.numpy_dtype == object:
+            if opname in ["__mul__", "__rmul__"]:
+                mark = pytest.mark.xfail(
+                    reason="the Series.combine step raises but not the Series method."
+                )
+                request.node.add_marker(mark)
+            series_scalar_exc = TypeError
+        self.series_scalar_exc = series_scalar_exc
         super().test_arith_series_with_scalar(data, all_arithmetic_operators)
 
-    def test_arith_series_with_array(self, data, all_arithmetic_operators, request):
+    def test_arith_series_with_array(self, data, all_arithmetic_operators):
         opname = all_arithmetic_operators
+        series_array_exc = None
         if data.dtype.numpy_dtype == object and opname not in ["__add__", "__radd__"]:
-            mark = pytest.mark.xfail(reason="Fails for object dtype")
-            request.applymarker(mark)
+            series_array_exc = TypeError
+        self.series_array_exc = series_array_exc
         super().test_arith_series_with_array(data, all_arithmetic_operators)
 
-    @skip_nested
-    def test_arith_frame_with_scalar(self, data, all_arithmetic_operators):
+    def test_arith_frame_with_scalar(self, data, all_arithmetic_operators, request):
+        opname = all_arithmetic_operators
+        frame_scalar_exc = None
+        if data.dtype.numpy_dtype == object:
+            if opname in ["__mul__", "__rmul__"]:
+                mark = pytest.mark.xfail(
+                    reason="the Series.combine step raises but not the Series method."
+                )
+                request.node.add_marker(mark)
+            frame_scalar_exc = TypeError
+        self.frame_scalar_exc = frame_scalar_exc
         super().test_arith_frame_with_scalar(data, all_arithmetic_operators)
 
-
-class TestPrinting(BaseNumPyTests, base.BasePrintingTests):
-    pass
-
-
-class TestReduce(BaseNumPyTests, base.BaseReduceTests):
     def _supports_reduction(self, ser: pd.Series, op_name: str) -> bool:
         if ser.dtype.kind == "O":
             return op_name in ["sum", "min", "max", "any", "all"]
@@ -328,8 +317,6 @@ def check_reduce(self, ser: pd.Series, op_name: str, skipna: bool):
     def test_reduce_frame(self, data, all_numeric_reductions, skipna):
         pass
 
-
-class TestMissing(BaseNumPyTests, base.BaseMissingTests):
     @skip_nested
     def test_fillna_series(self, data_missing):
         # Non-scalar "scalar" values.
@@ -340,12 +327,6 @@ def test_fillna_frame(self, data_missing):
         # Non-scalar "scalar" values.
         super().test_fillna_frame(data_missing)
 
-
-class TestReshaping(BaseNumPyTests, base.BaseReshapingTests):
-    pass
-
-
-class TestSetitem(BaseNumPyTests, base.BaseSetitemTests):
     @skip_nested
     def test_setitem_invalid(self, data, invalid_scalar):
         # object dtype can hold anything, so doesn't raise
@@ -431,11 +412,25 @@ def test_setitem_with_expansion_dataframe_column(self, data, full_indexer):
                 expected = pd.DataFrame({"data": data.to_numpy()})
         tm.assert_frame_equal(result, expected, check_column_type=False)
 
+    @pytest.mark.xfail(reason="NumpyEADtype is unpacked")
+    def test_index_from_listlike_with_dtype(self, data):
+        super().test_index_from_listlike_with_dtype(data)
 
-@skip_nested
-class TestParsing(BaseNumPyTests, base.BaseParsingTests):
-    pass
+    @skip_nested
+    @pytest.mark.parametrize("engine", ["c", "python"])
+    def test_EA_types(self, engine, data, request):
+        super().test_EA_types(engine, data, request)
+
+    @pytest.mark.xfail(reason="Expect NumpyEA, get np.ndarray")
+    def test_compare_array(self, data, comparison_op):
+        super().test_compare_array(data, comparison_op)
+
+    def test_compare_scalar(self, data, comparison_op, request):
+        if data.dtype.kind == "f" or comparison_op.__name__ in ["eq", "ne"]:
+            mark = pytest.mark.xfail(reason="Expect NumpyEA, get np.ndarray")
+            request.applymarker(mark)
+        super().test_compare_scalar(data, comparison_op)
 
 
-class Test2DCompat(BaseNumPyTests, base.NDArrayBacked2DTests):
+class Test2DCompat(base.NDArrayBacked2DTests):
     pass