Initial commit: 首次建仓，建立目录结构

dashboard/venv/lib/python3.12/site-packages/pandas/tests/extension/decimal/__init__.py

@@ -0,0 +1,8 @@
+from pandas.tests.extension.decimal.array import (
+    DecimalArray,
+    DecimalDtype,
+    make_data,
+    to_decimal,
+)
+
+__all__ = ["DecimalArray", "DecimalDtype", "make_data", "to_decimal"]

dashboard/venv/lib/python3.12/site-packages/pandas/tests/extension/decimal/array.py

@@ -0,0 +1,315 @@
+from __future__ import annotations
+
+import decimal
+import numbers
+import sys
+from typing import TYPE_CHECKING
+
+import numpy as np
+
+from pandas.core.dtypes.base import ExtensionDtype
+from pandas.core.dtypes.common import (
+    is_dtype_equal,
+    is_float,
+    is_integer,
+    pandas_dtype,
+)
+
+import pandas as pd
+from pandas.api.extensions import (
+    no_default,
+    register_extension_dtype,
+)
+from pandas.api.types import (
+    is_list_like,
+    is_scalar,
+)
+from pandas.core import arraylike
+from pandas.core.arraylike import OpsMixin
+from pandas.core.arrays import (
+    ExtensionArray,
+    ExtensionScalarOpsMixin,
+)
+from pandas.core.indexers import (
+    check_array_indexer,
+    getitem_returns_view,
+)
+
+if TYPE_CHECKING:
+    from pandas._typing import type_t
+
+
+@register_extension_dtype
+class DecimalDtype(ExtensionDtype):
+    type = decimal.Decimal
+    name = "decimal"
+    na_value = decimal.Decimal("NaN")
+    _metadata = ("context",)
+
+    def __init__(self, context=None) -> None:
+        self.context = context or decimal.getcontext()
+
+    def __repr__(self) -> str:
+        return f"DecimalDtype(context={self.context})"
+
+    def construct_array_type(self) -> type_t[DecimalArray]:
+        """
+        Return the array type associated with this dtype.
+
+        Returns
+        -------
+        type
+        """
+        return DecimalArray
+
+    @property
+    def _is_numeric(self) -> bool:
+        return True
+
+
+class DecimalArray(OpsMixin, ExtensionScalarOpsMixin, ExtensionArray):
+    __array_priority__ = 1000
+
+    def __init__(self, values, dtype=None, copy=False, context=None) -> None:
+        for i, val in enumerate(values):
+            if is_float(val) or is_integer(val):
+                if np.isnan(val):
+                    values[i] = DecimalDtype.na_value
+                else:
+                    # error: Argument 1 has incompatible type "float | int |
+                    # integer[Any]"; expected "Decimal | float | str | tuple[int,
+                    # Sequence[int], int]"
+                    values[i] = DecimalDtype.type(val)  # type: ignore[arg-type]
+            elif not isinstance(val, decimal.Decimal):
+                raise TypeError("All values must be of type " + str(decimal.Decimal))
+        values = np.asarray(values, dtype=object)
+
+        self._data = values
+        # Some aliases for common attribute names to ensure pandas supports
+        # these
+        self._items = self.data = self._data
+        # those aliases are currently not working due to assumptions
+        # in internal code (GH-20735)
+        # self._values = self.values = self.data
+        self._dtype = DecimalDtype(context)
+
+    @property
+    def dtype(self):
+        return self._dtype
+
+    @classmethod
+    def _from_sequence(cls, scalars, *, dtype=None, copy=False):
+        return cls(scalars)
+
+    @classmethod
+    def _from_sequence_of_strings(cls, strings, *, dtype: ExtensionDtype, copy=False):
+        return cls._from_sequence(
+            [decimal.Decimal(x) for x in strings], dtype=dtype, copy=copy
+        )
+
+    @classmethod
+    def _from_factorized(cls, values, original):
+        return cls(values)
+
+    # test to ensure that the base class _cast_pointwise_result works as expected
+    # def _cast_pointwise_result(self, values):
+    #     try:
+    #         # If this were ever made a non-test EA, special-casing could
+    #         #  be avoided by handling Decimal in maybe_convert_objects
+    #         res = type(self)._from_sequence(values, dtype=self.dtype)
+    #     except (ValueError, TypeError):
+    #         return values
+    #     return res
+
+    _HANDLED_TYPES = (decimal.Decimal, numbers.Number, np.ndarray)
+
+    def to_numpy(
+        self,
+        dtype=None,
+        copy: bool = False,
+        na_value: object = no_default,
+        decimals=None,
+    ) -> np.ndarray:
+        result = np.asarray(self, dtype=dtype)
+        if decimals is not None:
+            result = np.asarray([round(x, decimals) for x in result])
+        return result
+
+    def __array_ufunc__(self, ufunc: np.ufunc, method: str, *inputs, **kwargs):
+        if not all(isinstance(t, (*self._HANDLED_TYPES, DecimalArray)) for t in inputs):
+            return NotImplemented
+
+        result = arraylike.maybe_dispatch_ufunc_to_dunder_op(
+            self, ufunc, method, *inputs, **kwargs
+        )
+        if result is not NotImplemented:
+            # e.g. test_array_ufunc_series_scalar_other
+            return result
+
+        if "out" in kwargs:
+            return arraylike.dispatch_ufunc_with_out(
+                self, ufunc, method, *inputs, **kwargs
+            )
+
+        inputs = tuple(x._data if isinstance(x, DecimalArray) else x for x in inputs)
+        result = getattr(ufunc, method)(*inputs, **kwargs)
+
+        if method == "reduce":
+            result = arraylike.dispatch_reduction_ufunc(
+                self, ufunc, method, *inputs, **kwargs
+            )
+            if result is not NotImplemented:
+                return result
+
+        def reconstruct(x):
+            if isinstance(x, (decimal.Decimal, numbers.Number)):
+                return x
+            else:
+                return type(self)._from_sequence(x, dtype=self.dtype)
+
+        if ufunc.nout > 1:
+            return tuple(reconstruct(x) for x in result)
+        else:
+            return reconstruct(result)
+
+    def __getitem__(self, item):
+        if isinstance(item, numbers.Integral):
+            return self._data[item]
+        else:
+            # array, slice.
+            item = pd.api.indexers.check_array_indexer(self, item)
+            result = type(self)(self._data[item], context=self.dtype.context)
+            if getitem_returns_view(self, item):
+                result._readonly = self._readonly
+            return result
+
+    def take(self, indexer, allow_fill=False, fill_value=None):
+        from pandas.api.extensions import take
+
+        data = self._data
+        if allow_fill and fill_value is None:
+            fill_value = self.dtype.na_value
+
+        result = take(data, indexer, fill_value=fill_value, allow_fill=allow_fill)
+        return self._from_sequence(result, dtype=self.dtype)
+
+    def copy(self):
+        return type(self)(self._data.copy(), dtype=self.dtype)
+
+    def astype(self, dtype, copy=True):
+        if is_dtype_equal(dtype, self._dtype):
+            if not copy:
+                return self
+        dtype = pandas_dtype(dtype)
+        if isinstance(dtype, type(self.dtype)):
+            return type(self)(self._data, copy=copy, context=dtype.context)
+
+        return super().astype(dtype, copy=copy)
+
+    def __setitem__(self, key, value) -> None:
+        if self._readonly:
+            raise ValueError("Cannot modify read-only array")
+
+        if is_list_like(value):
+            if is_scalar(key):
+                raise ValueError("setting an array element with a sequence.")
+            value = [decimal.Decimal(v) for v in value]
+        else:
+            value = decimal.Decimal(value)
+
+        key = check_array_indexer(self, key)
+        self._data[key] = value
+
+    def __len__(self) -> int:
+        return len(self._data)
+
+    def __contains__(self, item) -> bool | np.bool_:
+        if not isinstance(item, decimal.Decimal):
+            return False
+        elif item.is_nan():
+            return self.isna().any()
+        else:
+            return super().__contains__(item)
+
+    @property
+    def nbytes(self) -> int:
+        n = len(self)
+        if n:
+            return n * sys.getsizeof(self[0])
+        return 0
+
+    def isna(self):
+        return np.array([x.is_nan() for x in self._data], dtype=bool)
+
+    @property
+    def _na_value(self):
+        return decimal.Decimal("NaN")
+
+    def _formatter(self, boxed=False):
+        if boxed:
+            return "Decimal: {}".format
+        return repr
+
+    @classmethod
+    def _concat_same_type(cls, to_concat):
+        return cls(np.concatenate([x._data for x in to_concat]))
+
+    def _reduce(
+        self, name: str, *, skipna: bool = True, keepdims: bool = False, **kwargs
+    ):
+        if skipna and self.isna().any():
+            # If we don't have any NAs, we can ignore skipna
+            other = self[~self.isna()]
+            result = other._reduce(name, **kwargs)
+        elif name == "sum" and len(self) == 0:
+            # GH#29630 avoid returning int 0 or np.bool_(False) on old numpy
+            result = decimal.Decimal(0)
+        else:
+            try:
+                op = getattr(self.data, name)
+            except AttributeError as err:
+                raise NotImplementedError(
+                    f"decimal does not support the {name} operation"
+                ) from err
+            result = op(axis=0)
+
+        if keepdims:
+            return type(self)([result])
+        else:
+            return result
+
+    def _cmp_method(self, other, op):
+        # For use with OpsMixin
+        def convert_values(param):
+            if isinstance(param, ExtensionArray) or is_list_like(param):
+                ovalues = param
+            else:
+                # Assume it's an object
+                ovalues = [param] * len(self)
+            return ovalues
+
+        lvalues = self
+        rvalues = convert_values(other)
+
+        # If the operator is not defined for the underlying objects,
+        # a TypeError should be raised
+        res = [op(a, b) for (a, b) in zip(lvalues, rvalues, strict=True)]
+
+        return np.asarray(res, dtype=bool)
+
+    # We override fillna here to simulate a 3rd party EA that has done so. This
+    #  lets us test a 3rd-party EA that has not yet updated to include a "copy"
+    #  keyword in its fillna method.
+    def fillna(self, value=None, limit=None):
+        return super().fillna(value=value, limit=limit, copy=True)
+
+
+def to_decimal(values, context=None):
+    return DecimalArray([decimal.Decimal(x) for x in values], context=context)
+
+
+def make_data(n: int):
+    return [decimal.Decimal(val) for val in np.random.default_rng(2).random(n)]
+
+
+DecimalArray._add_arithmetic_ops()

dashboard/venv/lib/python3.12/site-packages/pandas/tests/extension/decimal/test_decimal.py

@@ -0,0 +1,438 @@
+from __future__ import annotations
+
+import decimal
+
+import numpy as np
+import pytest
+
+from pandas.errors import Pandas4Warning
+
+import pandas as pd
+import pandas._testing as tm
+from pandas.tests.extension import base
+from pandas.tests.extension.decimal.array import (
+    DecimalArray,
+    DecimalDtype,
+    make_data,
+    to_decimal,
+)
+
+
+@pytest.fixture
+def dtype():
+    return DecimalDtype()
+
+
+@pytest.fixture
+def data():
+    return DecimalArray(make_data(10))
+
+
+@pytest.fixture
+def data_for_twos():
+    return DecimalArray([decimal.Decimal(2) for _ in range(10)])
+
+
+@pytest.fixture
+def data_missing():
+    return DecimalArray([decimal.Decimal("NaN"), decimal.Decimal(1)])
+
+
+@pytest.fixture
+def data_for_sorting():
+    return DecimalArray(
+        [decimal.Decimal("1"), decimal.Decimal("2"), decimal.Decimal("0")]
+    )
+
+
+@pytest.fixture
+def data_missing_for_sorting():
+    return DecimalArray(
+        [decimal.Decimal("1"), decimal.Decimal("NaN"), decimal.Decimal("0")]
+    )
+
+
+@pytest.fixture
+def na_cmp():
+    return lambda x, y: x.is_nan() and y.is_nan()
+
+
+@pytest.fixture
+def data_for_grouping():
+    b = decimal.Decimal("1.0")
+    a = decimal.Decimal("0.0")
+    c = decimal.Decimal("2.0")
+    na = decimal.Decimal("NaN")
+    return DecimalArray([b, b, na, na, a, a, b, c])
+
+
+class TestDecimalArray(base.ExtensionTests):
+    def _get_expected_exception(
+        self, op_name: str, obj, other
+    ) -> type[Exception] | tuple[type[Exception], ...] | None:
+        return None
+
+    def _supports_reduction(self, ser: pd.Series, op_name: str) -> bool:
+        if op_name in ["kurt", "sem"]:
+            return False
+        return True
+
+    def check_reduce(self, ser: pd.Series, op_name: str, skipna: bool):
+        if op_name == "count":
+            return super().check_reduce(ser, op_name, skipna)
+        else:
+            result = getattr(ser, op_name)(skipna=skipna)
+            expected = getattr(np.asarray(ser), op_name)()
+            tm.assert_almost_equal(result, expected)
+
+    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.applymarker(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"]:
+            mark = pytest.mark.xfail(raises=NotImplementedError)
+            request.applymarker(mark)
+
+        return super().test_reduce_frame(data, all_numeric_reductions, skipna)
+
+    def test_compare_scalar(self, data, comparison_op):
+        ser = pd.Series(data)
+        self._compare_other(ser, data, comparison_op, 0.5)
+
+    def test_compare_array(self, data, comparison_op):
+        ser = pd.Series(data)
+
+        alter = np.random.default_rng(2).choice([-1, 0, 1], len(data))
+        # Randomly double, halve or keep same value
+        other = pd.Series(data) * [decimal.Decimal(pow(2.0, i)) for i in alter]
+        self._compare_other(ser, data, comparison_op, other)
+
+    def test_arith_series_with_array(self, data, all_arithmetic_operators):
+        op_name = all_arithmetic_operators
+        ser = pd.Series(data)
+
+        context = decimal.getcontext()
+        divbyzerotrap = context.traps[decimal.DivisionByZero]
+        invalidoptrap = context.traps[decimal.InvalidOperation]
+        context.traps[decimal.DivisionByZero] = 0
+        context.traps[decimal.InvalidOperation] = 0
+
+        # Decimal supports ops with int, but not float
+        other = pd.Series([int(d * 100) for d in data])
+        self.check_opname(ser, op_name, other)
+
+        if "mod" not in op_name:
+            self.check_opname(ser, op_name, ser * 2)
+
+        self.check_opname(ser, op_name, 0)
+        self.check_opname(ser, op_name, 5)
+        context.traps[decimal.DivisionByZero] = divbyzerotrap
+        context.traps[decimal.InvalidOperation] = invalidoptrap
+
+    def test_fillna_frame(self, data_missing):
+        msg = "ExtensionArray.fillna added a 'copy' keyword"
+        with tm.assert_produces_warning(
+            Pandas4Warning, match=msg, check_stacklevel=False
+        ):
+            super().test_fillna_frame(data_missing)
+
+    def test_fillna_series(self, data_missing):
+        msg = "ExtensionArray.fillna added a 'copy' keyword"
+        with tm.assert_produces_warning(
+            DeprecationWarning, match=msg, check_stacklevel=False
+        ):
+            super().test_fillna_series(data_missing)
+
+    def test_fillna_with_none(self, data_missing):
+        # GH#57723
+        # EAs that don't have special logic for None will raise, unlike pandas'
+        # which interpret None as the NA value for the dtype.
+        msg = "conversion from NoneType to Decimal is not supported"
+        with pytest.raises(TypeError, match=msg):
+            super().test_fillna_with_none(data_missing)
+
+    def test_fillna_limit_frame(self, data_missing):
+        # GH#58001
+        msg = "ExtensionArray.fillna added a 'copy' keyword"
+        with tm.assert_produces_warning(
+            DeprecationWarning, match=msg, check_stacklevel=False
+        ):
+            super().test_fillna_limit_frame(data_missing)
+
+    def test_fillna_limit_series(self, data_missing):
+        # GH#58001
+        msg = "ExtensionArray.fillna added a 'copy' keyword"
+        with tm.assert_produces_warning(
+            DeprecationWarning, match=msg, check_stacklevel=False
+        ):
+            super().test_fillna_limit_series(data_missing)
+
+    @pytest.mark.xfail(reason="copy keyword is missing")
+    def test_fillna_readonly(self, data_missing):
+        super().test_fillna_readonly(data_missing)
+
+    def test_series_repr(self, data):
+        # Overriding this base test to explicitly test that
+        # the custom _formatter is used
+        ser = pd.Series(data)
+        assert data.dtype.name in repr(ser)
+        assert "Decimal: " in repr(ser)
+
+    @pytest.mark.xfail(reason="Inconsistent array-vs-scalar behavior")
+    @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)
+
+
+def test_take_na_value_other_decimal():
+    arr = DecimalArray([decimal.Decimal("1.0"), decimal.Decimal("2.0")])
+    result = arr.take([0, -1], allow_fill=True, fill_value=decimal.Decimal("-1.0"))
+    expected = DecimalArray([decimal.Decimal("1.0"), decimal.Decimal("-1.0")])
+    tm.assert_extension_array_equal(result, expected)
+
+
+def test_series_constructor_coerce_data_to_extension_dtype():
+    dtype = DecimalDtype()
+    ser = pd.Series([0, 1, 2], dtype=dtype)
+
+    arr = DecimalArray(
+        [decimal.Decimal(0), decimal.Decimal(1), decimal.Decimal(2)],
+        dtype=dtype,
+    )
+    exp = pd.Series(arr)
+    tm.assert_series_equal(ser, exp)
+
+
+def test_series_constructor_with_dtype():
+    arr = DecimalArray([decimal.Decimal("10.0")])
+    result = pd.Series(arr, dtype=DecimalDtype())
+    expected = pd.Series(arr)
+    tm.assert_series_equal(result, expected)
+
+    result = pd.Series(arr, dtype="int64")
+    expected = pd.Series([10])
+    tm.assert_series_equal(result, expected)
+
+
+def test_dataframe_constructor_with_dtype():
+    arr = DecimalArray([decimal.Decimal("10.0")])
+
+    result = pd.DataFrame({"A": arr}, dtype=DecimalDtype())
+    expected = pd.DataFrame({"A": arr})
+    tm.assert_frame_equal(result, expected)
+
+    arr = DecimalArray([decimal.Decimal("10.0")])
+    result = pd.DataFrame({"A": arr}, dtype="int64")
+    expected = pd.DataFrame({"A": [10]})
+    tm.assert_frame_equal(result, expected)
+
+
+def test_astype_dispatches(frame_or_series):
+    # This is a dtype-specific test that ensures Series[decimal].astype
+    # gets all the way through to ExtensionArray.astype
+    # Designing a reliable smoke test that works for arbitrary data types
+    # is difficult.
+    data = pd.Series(DecimalArray([decimal.Decimal(2)]), name="a")
+    ctx = decimal.Context()
+    ctx.prec = 5
+
+    data = frame_or_series(data)
+
+    result = data.astype(DecimalDtype(ctx))
+
+    if frame_or_series is pd.DataFrame:
+        result = result["a"]
+
+    assert result.dtype.context.prec == ctx.prec
+
+
+class DecimalArrayWithoutFromSequence(DecimalArray):
+    """Helper class for testing error handling in _from_sequence."""
+
+    @classmethod
+    def _from_sequence(cls, scalars, *, dtype=None, copy=False):
+        raise KeyError("For the test")
+
+
+class DecimalArrayWithoutCoercion(DecimalArrayWithoutFromSequence):
+    @classmethod
+    def _create_arithmetic_method(cls, op):
+        return cls._create_method(op, coerce_to_dtype=False)
+
+
+DecimalArrayWithoutCoercion._add_arithmetic_ops()
+
+
+def test_scalar_ops_from_sequence_raises():
+    # op(EA, EA) should return an EA, or an ndarray if it's not possible
+    # to return an EA with the return values.
+    arr = DecimalArrayWithoutCoercion([decimal.Decimal("1.0"), decimal.Decimal("2.0")])
+    result = arr + arr
+    expected = np.array(
+        [decimal.Decimal("2.0"), decimal.Decimal("4.0")], dtype="object"
+    )
+    tm.assert_numpy_array_equal(result, expected)
+
+
+@pytest.mark.parametrize(
+    "reverse, expected_div, expected_mod",
+    [(False, [0, 1, 1, 2], [1, 0, 1, 0]), (True, [2, 1, 0, 0], [0, 0, 2, 2])],
+)
+def test_divmod_array(reverse, expected_div, expected_mod):
+    # https://github.com/pandas-dev/pandas/issues/22930
+    arr = to_decimal([1, 2, 3, 4])
+    if reverse:
+        div, mod = divmod(2, arr)
+    else:
+        div, mod = divmod(arr, 2)
+    expected_div = to_decimal(expected_div)
+    expected_mod = to_decimal(expected_mod)
+
+    tm.assert_extension_array_equal(div, expected_div)
+    tm.assert_extension_array_equal(mod, expected_mod)
+
+
+def test_ufunc_fallback(data):
+    a = data[:5]
+    s = pd.Series(a, index=range(3, 8))
+    result = np.abs(s)
+    expected = pd.Series(np.abs(a), index=range(3, 8))
+    tm.assert_series_equal(result, expected)
+
+
+def test_array_ufunc():
+    a = to_decimal([1, 2, 3])
+    result = np.exp(a)
+    expected = to_decimal(np.exp(a._data))
+    tm.assert_extension_array_equal(result, expected)
+
+
+def test_array_ufunc_series():
+    a = to_decimal([1, 2, 3])
+    s = pd.Series(a)
+    result = np.exp(s)
+    expected = pd.Series(to_decimal(np.exp(a._data)))
+    tm.assert_series_equal(result, expected)
+
+
+def test_array_ufunc_series_scalar_other():
+    # check _HANDLED_TYPES
+    a = to_decimal([1, 2, 3])
+    s = pd.Series(a)
+    result = np.add(s, decimal.Decimal(1))
+    expected = pd.Series(np.add(a, decimal.Decimal(1)))
+    tm.assert_series_equal(result, expected)
+
+
+def test_array_ufunc_series_defer():
+    a = to_decimal([1, 2, 3])
+    s = pd.Series(a)
+
+    expected = pd.Series(to_decimal([2, 4, 6]))
+    r1 = np.add(s, a)
+    r2 = np.add(a, s)
+
+    tm.assert_series_equal(r1, expected)
+    tm.assert_series_equal(r2, expected)
+
+
+def test_groupby_agg():
+    # Ensure that the result of agg is inferred to be decimal dtype
+    # https://github.com/pandas-dev/pandas/issues/29141
+
+    data = make_data(5)
+    df = pd.DataFrame(
+        {"id1": [0, 0, 0, 1, 1], "id2": [0, 1, 0, 1, 1], "decimals": DecimalArray(data)}
+    )
+
+    # single key, selected column
+    expected = pd.Series(to_decimal([data[0], data[3]]))
+    result = df.groupby("id1")["decimals"].agg(lambda x: x.iloc[0])
+    tm.assert_series_equal(result, expected, check_names=False)
+    result = df["decimals"].groupby(df["id1"]).agg(lambda x: x.iloc[0])
+    tm.assert_series_equal(result, expected, check_names=False)
+
+    # multiple keys, selected column
+    expected = pd.Series(
+        to_decimal([data[0], data[1], data[3]]),
+        index=pd.MultiIndex.from_tuples([(0, 0), (0, 1), (1, 1)]),
+    )
+    result = df.groupby(["id1", "id2"])["decimals"].agg(lambda x: x.iloc[0])
+    tm.assert_series_equal(result, expected, check_names=False)
+    result = df["decimals"].groupby([df["id1"], df["id2"]]).agg(lambda x: x.iloc[0])
+    tm.assert_series_equal(result, expected, check_names=False)
+
+    # multiple columns
+    expected = pd.DataFrame({"id2": [0, 1], "decimals": to_decimal([data[0], data[3]])})
+    result = df.groupby("id1").agg(lambda x: x.iloc[0])
+    tm.assert_frame_equal(result, expected, check_names=False)
+
+
+def test_groupby_agg_ea_method(monkeypatch):
+    # Ensure that the result of agg is inferred to be decimal dtype
+    # https://github.com/pandas-dev/pandas/issues/29141
+
+    def DecimalArray__my_sum(self):
+        return np.sum(np.array(self))
+
+    monkeypatch.setattr(DecimalArray, "my_sum", DecimalArray__my_sum, raising=False)
+
+    data = make_data(5)
+    df = pd.DataFrame({"id": [0, 0, 0, 1, 1], "decimals": DecimalArray(data)})
+    expected = pd.Series(to_decimal([data[0] + data[1] + data[2], data[3] + data[4]]))
+
+    result = df.groupby("id")["decimals"].agg(lambda x: x.values.my_sum())
+    tm.assert_series_equal(result, expected, check_names=False)
+    s = pd.Series(DecimalArray(data))
+    grouper = np.array([0, 0, 0, 1, 1], dtype=np.int64)
+    result = s.groupby(grouper).agg(lambda x: x.values.my_sum())
+    tm.assert_series_equal(result, expected, check_names=False)
+
+
+def test_indexing_no_materialize(monkeypatch):
+    # See https://github.com/pandas-dev/pandas/issues/29708
+    # Ensure that indexing operations do not materialize (convert to a numpy
+    # array) the ExtensionArray unnecessary
+
+    def DecimalArray__array__(self, dtype=None):
+        raise Exception("tried to convert a DecimalArray to a numpy array")
+
+    monkeypatch.setattr(DecimalArray, "__array__", DecimalArray__array__, raising=False)
+
+    data = make_data(10)
+    s = pd.Series(DecimalArray(data))
+    df = pd.DataFrame({"a": s, "b": range(len(s))})
+
+    # ensure the following operations do not raise an error
+    s[s > 0.5]
+    df[s > 0.5]
+    s.at[0]
+    df.at[0, "a"]
+
+
+def test_to_numpy_keyword():
+    # test the extra keyword
+    values = [decimal.Decimal("1.1111"), decimal.Decimal("2.2222")]
+    expected = np.array(
+        [decimal.Decimal("1.11"), decimal.Decimal("2.22")], dtype="object"
+    )
+    a = pd.array(values, dtype="decimal")
+    result = a.to_numpy(decimals=2)
+    tm.assert_numpy_array_equal(result, expected)
+
+    result = pd.Series(a).to_numpy(decimals=2)
+    tm.assert_numpy_array_equal(result, expected)
+
+
+def test_array_copy_on_write():
+    df = pd.DataFrame({"a": [decimal.Decimal(2), decimal.Decimal(3)]}, dtype="object")
+    df2 = df.astype(DecimalDtype())
+    df.iloc[0, 0] = 0
+    expected = pd.DataFrame(
+        {"a": [decimal.Decimal(2), decimal.Decimal(3)]}, dtype=DecimalDtype()
+    )
+    tm.assert_equal(df2.values, expected.values)