# Licensed under a 3-clause BSD style license - see LICENSE.rst
"""Test behavior related to masked tables"""

import numpy as np
import numpy.ma as ma
import pytest

import astropy.units as u
from astropy.table import Column, MaskedColumn, QTable, Table
from astropy.table.column import BaseColumn
from astropy.time import Time
from astropy.utils.masked import Masked


class SetupData:
    def setup_method(self, method):
        self.a = MaskedColumn(name="a", data=[1, 2, 3], fill_value=1)
        self.b = MaskedColumn(name="b", data=[4, 5, 6], mask=True)
        self.c = MaskedColumn(name="c", data=[7, 8, 9], mask=False)
        self.d_mask = np.array([False, True, False])
        self.d = MaskedColumn(name="d", data=[7, 8, 7], mask=self.d_mask)
        self.t = Table([self.a, self.b], masked=True)
        self.ca = Column(name="ca", data=[1, 2, 3])
        self.sc = MaskedColumn(
            name="sc",
            data=[(1, 1.0), (2, 2.0), (3, 3.0)],
            dtype="i8,f8",
            fill_value=(0, -1.0),
        )


class TestPprint(SetupData):
    def test_pformat(self):
        assert self.t.pformat() == [
            " a   b ",
            "--- ---",
            "  1  --",
            "  2  --",
            "  3  --",
        ]


class TestFilled:
    """Test the filled method in MaskedColumn and Table"""

    def setup_method(self, method):
        mask = [True, False, False]
        self.meta = {"a": 1, "b": [2, 3]}
        self.a = MaskedColumn(
            name="a", data=[1, 2, 3], fill_value=10, mask=mask, meta={"a": 1}
        )
        self.b = MaskedColumn(
            name="b", data=[4.0, 5.0, 6.0], fill_value=10.0, mask=mask
        )
        self.c = MaskedColumn(name="c", data=["7", "8", "9"], fill_value="1", mask=mask)

    def test_filled_column(self):
        f = self.a.filled()
        assert np.all(f == [10, 2, 3])
        assert isinstance(f, Column)
        assert not isinstance(f, MaskedColumn)

        # Confirm copy, not ref
        assert f.meta["a"] == 1
        f.meta["a"] = 2
        f[1] = 100
        assert self.a[1] == 2
        assert self.a.meta["a"] == 1

        # Fill with arg fill_value not column fill_value
        f = self.a.filled(20)
        assert np.all(f == [20, 2, 3])

        f = self.b.filled()
        assert np.all(f == [10.0, 5.0, 6.0])
        assert isinstance(f, Column)

        f = self.c.filled()
        assert np.all(f == ["1", "8", "9"])
        assert isinstance(f, Column)

    def test_filled_masked_table(self, tableclass):
        t = tableclass([self.a, self.b, self.c], meta=self.meta)

        f = t.filled()
        assert isinstance(f, Table)
        assert f.masked is False
        assert np.all(f["a"] == [10, 2, 3])
        assert np.allclose(f["b"], [10.0, 5.0, 6.0])
        assert np.all(f["c"] == ["1", "8", "9"])

        # Confirm copy, not ref
        assert f.meta["b"] == [2, 3]
        f.meta["b"][0] = 20
        assert t.meta["b"] == [2, 3]
        f["a"][2] = 100
        assert t["a"][2] == 3

    def test_filled_unmasked_table(self, tableclass):
        t = tableclass([(1, 2), ("3", "4")], names=("a", "b"), meta=self.meta)
        f = t.filled()
        assert isinstance(f, Table)
        assert f.masked is False
        assert np.all(f["a"] == t["a"])
        assert np.all(f["b"] == t["b"])

        # Confirm copy, not ref
        assert f.meta["b"] == [2, 3]
        f.meta["b"][0] = 20
        assert t.meta["b"] == [2, 3]
        f["a"][1] = 100
        assert t["a"][1] == 2


class TestFillValue(SetupData):
    """Test setting and getting fill value in MaskedColumn and Table"""

    def test_init_set_fill_value(self):
        """Check that setting fill_value in the MaskedColumn init works"""
        assert self.a.fill_value == 1
        c = MaskedColumn(name="c", data=["xxxx", "yyyy"], fill_value="none")
        assert c.fill_value == "none"

    def test_set_get_fill_value_for_bare_column(self):
        """Check set and get of fill value works for bare Column"""
        self.d.fill_value = -999
        assert self.d.fill_value == -999
        assert np.all(self.d.filled() == [7, -999, 7])

    def test_set_get_fill_value_for_str_column(self):
        c = MaskedColumn(name="c", data=["xxxx", "yyyy"], mask=[True, False])
        # assert np.all(c.filled() == ['N/A', 'yyyy'])
        c.fill_value = "ABCDEF"
        assert c.fill_value == "ABCD"  # string truncated to dtype length
        assert np.all(c.filled() == ["ABCD", "yyyy"])
        assert np.all(c.filled("XY") == ["XY", "yyyy"])

    def test_set_get_fill_value_for_structured_column(self):
        assert self.sc.fill_value == np.array((0, -1.0), self.sc.dtype)
        sc = self.sc.copy()
        assert sc.fill_value.item() == (0, -1.0)
        sc.fill_value = (-1, np.inf)
        assert sc.fill_value == np.array((-1, np.inf), self.sc.dtype)
        sc2 = MaskedColumn(sc, fill_value=(-2, -np.inf))
        assert sc2.fill_value == np.array((-2, -np.inf), sc2.dtype)

    def test_table_column_mask_not_ref(self):
        """Table column mask is not ref of original column mask"""
        self.b.fill_value = -999
        assert self.t["b"].fill_value != -999

    def test_set_get_fill_value_for_table_column(self):
        """Check set and get of fill value works for Column in a Table"""
        self.t["b"].fill_value = 1
        assert self.t["b"].fill_value == 1
        assert np.all(self.t["b"].filled() == [1, 1, 1])

    def test_data_attribute_fill_and_mask(self):
        """Check that .data attribute preserves fill_value and mask"""
        self.t["b"].fill_value = 1
        self.t["b"].mask = [True, False, True]
        assert self.t["b"].data.fill_value == 1
        assert np.all(self.t["b"].data.mask == [True, False, True])


class TestMaskedColumnInit(SetupData):
    """Initialization of a masked column"""

    def test_set_mask_and_not_ref(self):
        """Check that mask gets set properly and that it is a copy, not ref"""
        assert np.all(~self.a.mask)
        assert np.all(self.b.mask)
        assert np.all(~self.c.mask)
        assert np.all(self.d.mask == self.d_mask)
        self.d.mask[0] = True
        assert not np.all(self.d.mask == self.d_mask)

    def test_set_mask_from_list(self):
        """Set mask from a list"""
        mask_list = [False, True, False]
        a = MaskedColumn(name="a", data=[1, 2, 3], mask=mask_list)
        assert np.all(a.mask == mask_list)

    def test_override_existing_mask(self):
        """Override existing mask values"""
        mask_list = [False, True, False]
        b = MaskedColumn(name="b", data=self.b, mask=mask_list)
        assert np.all(b.mask == mask_list)

    def test_incomplete_mask_spec(self):
        """Incomplete mask specification raises MaskError"""
        mask_list = [False, True]
        with pytest.raises(ma.MaskError):
            MaskedColumn(name="b", length=4, mask=mask_list)


class TestTableInit(SetupData):
    """Initializing a table"""

    @pytest.mark.parametrize("type_str", ("?", "b", "i2", "f4", "c8", "S", "U", "O"))
    @pytest.mark.parametrize("shape", ((8,), (4, 2), (2, 2, 2)))
    def test_init_from_sequence_data_numeric_typed(self, type_str, shape):
        """Test init from list or list of lists with dtype specified, optionally
        including an np.ma.masked element.
        """
        # Make data of correct dtype and shape, then turn into a list,
        # then use that to init Table with spec'd type_str.
        data = list(range(8))
        np_data = np.array(data, dtype=type_str).reshape(shape)
        np_data_list = np_data.tolist()
        t = Table([np_data_list], dtype=[type_str])
        col = t["col0"]
        assert col.dtype == np_data.dtype
        assert np.all(col == np_data)
        assert type(col) is Column

        # Introduce np.ma.masked in the list input and confirm dtype still OK.
        if len(shape) == 1:
            np_data_list[-1] = np.ma.masked
        elif len(shape) == 2:
            np_data_list[-1][-1] = np.ma.masked
        else:
            np_data_list[-1][-1][-1] = np.ma.masked
        last_idx = tuple(-1 for _ in shape)
        t = Table([np_data_list], dtype=[type_str])
        col = t["col0"]
        assert col.dtype == np_data.dtype
        assert np.all(col == np_data)
        assert col.mask[last_idx]
        assert type(col) is MaskedColumn

    @pytest.mark.parametrize("type_str", ("?", "b", "i2", "f4", "c8", "S", "U", "O"))
    @pytest.mark.parametrize("shape", ((8,), (4, 2), (2, 2, 2)))
    def test_init_from_sequence_data_numeric_untyped(self, type_str, shape):
        """Test init from list or list of lists with dtype NOT specified,
        optionally including an np.ma.masked element.
        """
        data = list(range(8))
        np_data = np.array(data, dtype=type_str).reshape(shape)
        np_data_list = np_data.tolist()
        t = Table([np_data_list])
        # Grab the dtype that numpy assigns for the Python list inputs
        dtype_expected = t["col0"].dtype

        # Introduce np.ma.masked in the list input and confirm dtype still OK.
        if len(shape) == 1:
            np_data_list[-1] = np.ma.masked
        elif len(shape) == 2:
            np_data_list[-1][-1] = np.ma.masked
        else:
            np_data_list[-1][-1][-1] = np.ma.masked
        last_idx = tuple(-1 for _ in shape)
        t = Table([np_data_list])
        col = t["col0"]

        # Confirm dtype is same as for untype list input w/ no mask
        assert col.dtype == dtype_expected
        assert np.all(col == np_data)
        assert col.mask[last_idx]
        assert type(col) is MaskedColumn

    def test_initialization_with_all_columns(self):
        t1 = Table([self.a, self.b, self.c, self.d, self.ca, self.sc])
        assert t1.colnames == ["a", "b", "c", "d", "ca", "sc"]
        # Check we get the same result by passing in as list of dict.
        # (Regression test for error uncovered by scintillometry package.)
        lofd = [{k: row[k] for k in t1.colnames} for row in t1]
        t2 = Table(lofd)
        for k in t1.colnames:
            assert t1[k].dtype == t2[k].dtype
            assert np.all(t1[k] == t2[k]) in (True, np.ma.masked)
            assert np.all(
                getattr(t1[k], "mask", False) == getattr(t2[k], "mask", False)
            )

    def test_mask_false_if_input_mask_not_true(self):
        """Masking is always False if initial masked arg is not True"""
        t = Table([self.ca, self.a])
        assert t.masked is False  # True before astropy 4.0
        t = Table([self.ca])
        assert t.masked is False
        t = Table([self.ca, ma.array([1, 2, 3])])
        assert t.masked is False  # True before astropy 4.0

    def test_mask_false_if_no_input_masked(self):
        """Masking not true if not (requested or input requires mask)"""
        t0 = Table([[3, 4]], masked=False)
        t1 = Table(t0, masked=True)
        t2 = Table(t1, masked=False)
        assert not t0.masked
        assert t1.masked
        assert not t2.masked

    def test_mask_property(self):
        t = self.t
        # Access table mask (boolean structured array) by column name
        assert np.all(t.mask["a"] == np.array([False, False, False]))
        assert np.all(t.mask["b"] == np.array([True, True, True]))
        # Check that setting mask from table mask has the desired effect on column
        t.mask["b"] = np.array([False, True, False])
        assert np.all(t["b"].mask == np.array([False, True, False]))
        # Non-masked table returns None for mask attribute
        t2 = Table([self.ca], masked=False)
        assert t2.mask is None
        # Set mask property globally and verify local correctness
        for mask in (True, False):
            t.mask = mask
            for name in ("a", "b"):
                assert np.all(t[name].mask == mask)


class TestAddColumn:
    def test_add_masked_column_to_masked_table(self):
        t = Table(masked=True)
        assert t.masked
        t.add_column(MaskedColumn(name="a", data=[1, 2, 3], mask=[0, 1, 0]))
        assert t.masked
        t.add_column(MaskedColumn(name="b", data=[4, 5, 6], mask=[1, 0, 1]))
        assert t.masked
        assert isinstance(t["a"], MaskedColumn)
        assert isinstance(t["b"], MaskedColumn)
        assert np.all(t["a"] == np.array([1, 2, 3]))
        assert np.all(t["a"].mask == np.array([0, 1, 0], bool))
        assert np.all(t["b"] == np.array([4, 5, 6]))
        assert np.all(t["b"].mask == np.array([1, 0, 1], bool))

    def test_add_masked_column_to_non_masked_table(self):
        t = Table(masked=False)
        assert not t.masked
        t.add_column(Column(name="a", data=[1, 2, 3]))
        assert not t.masked
        t.add_column(MaskedColumn(name="b", data=[4, 5, 6], mask=[1, 0, 1]))
        assert not t.masked  # Changed in 4.0, table no longer auto-upgrades
        assert isinstance(t["a"], Column)  # Was MaskedColumn before 4.0
        assert isinstance(t["b"], MaskedColumn)
        assert np.all(t["a"] == np.array([1, 2, 3]))
        assert not hasattr(t["a"], "mask")
        assert np.all(t["b"] == np.array([4, 5, 6]))
        assert np.all(t["b"].mask == np.array([1, 0, 1], bool))

    def test_add_non_masked_column_to_masked_table(self):
        t = Table(masked=True)
        assert t.masked
        t.add_column(Column(name="a", data=[1, 2, 3]))
        assert t.masked
        t.add_column(MaskedColumn(name="b", data=[4, 5, 6], mask=[1, 0, 1]))
        assert t.masked
        assert isinstance(t["a"], MaskedColumn)
        assert isinstance(t["b"], MaskedColumn)
        assert np.all(t["a"] == np.array([1, 2, 3]))
        assert np.all(t["a"].mask == np.array([0, 0, 0], bool))
        assert np.all(t["b"] == np.array([4, 5, 6]))
        assert np.all(t["b"].mask == np.array([1, 0, 1], bool))

    def test_convert_to_masked_table_only_if_necessary(self):
        # Do not convert to masked table, if new column has no masked value.
        # See #1185 for details.
        t = Table(masked=False)
        assert not t.masked
        t.add_column(Column(name="a", data=[1, 2, 3]))
        assert not t.masked
        t.add_column(MaskedColumn(name="b", data=[4, 5, 6], mask=[0, 0, 0]))
        assert not t.masked
        assert np.all(t["a"] == np.array([1, 2, 3]))
        assert np.all(t["b"] == np.array([4, 5, 6]))


class TestRenameColumn:
    def test_rename_masked_column(self):
        t = Table(masked=True)
        t.add_column(MaskedColumn(name="a", data=[1, 2, 3], mask=[0, 1, 0]))
        t["a"].fill_value = 42
        t.rename_column("a", "b")
        assert t.masked
        assert np.all(t["b"] == np.array([1, 2, 3]))
        assert np.all(t["b"].mask == np.array([0, 1, 0], bool))
        assert t["b"].fill_value == 42
        assert t.colnames == ["b"]


class TestRemoveColumn:
    def test_remove_masked_column(self):
        t = Table(masked=True)
        t.add_column(MaskedColumn(name="a", data=[1, 2, 3], mask=[0, 1, 0]))
        t["a"].fill_value = 42
        t.add_column(MaskedColumn(name="b", data=[4, 5, 6], mask=[1, 0, 1]))
        t.remove_column("b")
        assert t.masked
        assert np.all(t["a"] == np.array([1, 2, 3]))
        assert np.all(t["a"].mask == np.array([0, 1, 0], bool))
        assert t["a"].fill_value == 42
        assert t.colnames == ["a"]


class TestAddRow:
    def test_add_masked_row_to_masked_table_iterable(self):
        t = Table(masked=True)
        t.add_column(MaskedColumn(name="a", data=[1], mask=[0]))
        t.add_column(MaskedColumn(name="b", data=[4], mask=[1]))
        t.add_row([2, 5], mask=[1, 0])
        t.add_row([3, 6], mask=[0, 1])
        assert t.masked
        assert np.all(np.array(t["a"]) == np.array([1, 2, 3]))
        assert np.all(t["a"].mask == np.array([0, 1, 0], bool))
        assert np.all(np.array(t["b"]) == np.array([4, 5, 6]))
        assert np.all(t["b"].mask == np.array([1, 0, 1], bool))

    def test_add_masked_row_to_masked_table_mapping1(self):
        t = Table(masked=True)
        t.add_column(MaskedColumn(name="a", data=[1], mask=[0]))
        t.add_column(MaskedColumn(name="b", data=[4], mask=[1]))
        t.add_row({"b": 5, "a": 2}, mask={"a": 1, "b": 0})
        t.add_row({"a": 3, "b": 6}, mask={"b": 1, "a": 0})
        assert t.masked
        assert np.all(np.array(t["a"]) == np.array([1, 2, 3]))
        assert np.all(t["a"].mask == np.array([0, 1, 0], bool))
        assert np.all(np.array(t["b"]) == np.array([4, 5, 6]))
        assert np.all(t["b"].mask == np.array([1, 0, 1], bool))

    def test_add_masked_row_to_masked_table_mapping2(self):
        # When adding values to a masked table, if the mask is specified as a
        # dict, then values not specified will have mask values set to True
        t = Table(masked=True)
        t.add_column(MaskedColumn(name="a", data=[1], mask=[0]))
        t.add_column(MaskedColumn(name="b", data=[4], mask=[1]))
        t.add_row({"b": 5}, mask={"b": 0})
        t.add_row({"a": 3}, mask={"a": 0})
        assert t.masked
        assert t["a"][0] == 1 and t["a"][2] == 3
        assert np.all(t["a"].mask == np.array([0, 1, 0], bool))
        assert t["b"][1] == 5
        assert np.all(t["b"].mask == np.array([1, 0, 1], bool))

    def test_add_masked_row_to_masked_table_mapping3(self):
        # When adding values to a masked table, if mask is not passed to
        # add_row, then the mask should be set to False if values are present
        # and True if not.
        t = Table(masked=True)
        t.add_column(MaskedColumn(name="a", data=[1], mask=[0]))
        t.add_column(MaskedColumn(name="b", data=[4], mask=[1]))
        t.add_row({"b": 5})
        t.add_row({"a": 3})
        assert t.masked
        assert t["a"][0] == 1 and t["a"][2] == 3
        assert np.all(t["a"].mask == np.array([0, 1, 0], bool))
        assert t["b"][1] == 5
        assert np.all(t["b"].mask == np.array([1, 0, 1], bool))

    def test_add_masked_row_to_masked_table_mapping4(self):
        # When adding values to a masked table, if the mask is specified as a
        # dict, then keys in values should match keys in mask
        t = Table(masked=True)
        t.add_column(MaskedColumn(name="a", data=[1], mask=[0]))
        t.add_column(MaskedColumn(name="b", data=[4], mask=[1]))
        with pytest.raises(ValueError) as exc:
            t.add_row({"b": 5}, mask={"a": True})
        assert exc.value.args[0] == "keys in mask should match keys in vals"

    def test_add_masked_row_to_masked_table_mismatch(self):
        t = Table(masked=True)
        t.add_column(MaskedColumn(name="a", data=[1], mask=[0]))
        t.add_column(MaskedColumn(name="b", data=[4], mask=[1]))
        with pytest.raises(TypeError) as exc:
            t.add_row([2, 5], mask={"a": 1, "b": 0})
        assert exc.value.args[0] == "Mismatch between type of vals and mask"
        with pytest.raises(TypeError) as exc:
            t.add_row({"b": 5, "a": 2}, mask=[1, 0])
        assert exc.value.args[0] == "Mismatch between type of vals and mask"

    def test_add_masked_row_to_non_masked_table_iterable(self):
        t = Table(masked=False)
        t["a"] = [1]
        t["b"] = [4]
        t["c"] = Time([1], format="cxcsec")

        tm = Time(2, format="cxcsec")
        assert not t.masked
        t.add_row([2, 5, tm])
        assert not t.masked
        t.add_row([3, 6, tm], mask=[0, 1, 1])
        assert not t.masked

        assert type(t["a"]) is Column
        assert type(t["b"]) is MaskedColumn
        assert type(t["c"]) is Time

        assert np.all(t["a"] == [1, 2, 3])
        assert np.all(t["b"].data == [4, 5, 6])
        assert np.all(t["b"].mask == [False, False, True])
        assert np.all(t["c"][:2] == Time([1, 2], format="cxcsec"))
        assert np.all(t["c"].mask == [False, False, True])

    def test_add_row_cannot_mask_column_raises_typeerror(self):
        t = QTable()
        t["a"] = [1, 2] * u.m
        t.add_row((3 * u.m,))  # No problem
        with pytest.raises(ValueError) as exc:
            t.add_row((3 * u.m,), mask=(True,))
        assert exc.value.args[0].splitlines() == [
            "Unable to insert row because of exception in column 'a':",
            "mask was supplied for column 'a' but it does not support masked values",
        ]


def test_setting_from_masked_column():
    """Test issue in #2997"""
    mask_b = np.array([True, True, False, False])
    for select in (mask_b, slice(0, 2)):
        t = Table(masked=True)
        t["a"] = Column([1, 2, 3, 4])
        t["b"] = MaskedColumn([11, 22, 33, 44], mask=mask_b)
        t["c"] = MaskedColumn([111, 222, 333, 444], mask=[True, False, True, False])

        t["b"][select] = t["c"][select]
        assert t["b"][1] == t[1]["b"]
        assert t["b"][0] is np.ma.masked  # Original state since t['c'][0] is masked
        assert t["b"][1] == 222  # New from t['c'] since t['c'][1] is unmasked
        assert t["b"][2] == 33
        assert t["b"][3] == 44
        assert np.all(
            t["b"].mask == t.mask["b"]
        )  # Avoid t.mask in general, this is for testing

        mask_before_add = t.mask.copy()
        t["d"] = np.arange(len(t))
        assert np.all(t.mask["b"] == mask_before_add["b"])


def test_coercing_fill_value_type():
    """
    Test that masked column fill_value is coerced into the correct column type.
    """
    # This is the original example posted on the astropy@scipy mailing list
    t = Table({"a": ["1"]}, masked=True)
    t["a"].set_fill_value("0")
    t2 = Table(t, names=["a"], dtype=[np.int32])
    assert isinstance(t2["a"].fill_value, np.int32)

    # Unit test the same thing.
    c = MaskedColumn(["1"])
    c.set_fill_value("0")
    c2 = MaskedColumn(c, dtype=np.int32)
    assert isinstance(c2.fill_value, np.int32)


def test_mask_copy():
    """Test that the mask is copied when copying a table (issue #7362)."""

    c = MaskedColumn([1, 2], mask=[False, True])
    c2 = MaskedColumn(c, copy=True)
    c2.mask[0] = True
    assert np.all(c.mask == [False, True])
    assert np.all(c2.mask == [True, True])


def test_masked_as_array_with_mixin():
    """Test that as_array() and Table.mask attr work with masked mixin columns"""
    t = Table()
    t["a"] = Time([1, 2], format="cxcsec")
    t["b"] = [3, 4]
    t["c"] = [5, 6] * u.m

    # With no mask, the output should be ndarray
    ta = t.as_array()
    assert isinstance(ta, np.ndarray) and not isinstance(ta, np.ma.MaskedArray)

    # With a mask, output is MaskedArray
    t["a"][1] = np.ma.masked
    ta = t.as_array()
    assert isinstance(ta, np.ma.MaskedArray)
    assert np.all(ta["a"].mask == [False, True])
    assert np.isclose(ta["a"][0].cxcsec, 1.0)
    assert not np.any(ta["b"].mask)
    assert not np.any(ta["c"].mask)

    # Check table ``mask`` property
    tm = t.mask
    assert np.all(tm["a"] == [False, True])
    assert not np.any(tm["b"])
    assert not np.any(tm["c"])


def test_masked_column_with_unit_in_qtable():
    """Test that adding a MaskedColumn with a unit to QTable creates a MaskedQuantity."""
    MaskedQuantity = Masked(u.Quantity)

    t = QTable()
    t["a"] = MaskedColumn([1, 2])
    assert isinstance(t["a"], MaskedColumn)

    t["b"] = MaskedColumn([1, 2], unit=u.m)
    assert isinstance(t["b"], MaskedQuantity)
    assert not np.any(t["b"].mask)

    t["c"] = MaskedColumn([1, 2], unit=u.m, mask=[True, False])
    assert isinstance(t["c"], MaskedQuantity)
    assert np.all(t["c"].mask == [True, False])


def test_masked_quantity_in_table():
    MaskedQuantity = Masked(u.Quantity)
    t = Table()
    t["b"] = MaskedQuantity([1, 2], unit=u.m)
    assert isinstance(t["b"], MaskedColumn)
    assert not np.any(t["b"].mask)

    t["c"] = MaskedQuantity([1, 2], unit=u.m, mask=[True, False])
    assert isinstance(t["c"], MaskedColumn)
    assert np.all(t["c"].mask == [True, False])


def test_masked_column_data_attribute_is_plain_masked_array():
    c = MaskedColumn([1, 2], mask=[False, True])
    c_data = c.data
    assert type(c_data) is np.ma.MaskedArray
    assert type(c_data.data) is np.ndarray


def test_mask_slicing_count_array_finalize():
    """Check that we don't finalize MaskedColumn too often.

    Regression test for gh-6721.
    """

    # Create a new BaseColumn class that counts how often
    # ``__array_finalize__`` is called.
    class MyBaseColumn(BaseColumn):
        counter = 0

        def __array_finalize__(self, obj):
            super().__array_finalize__(obj)
            MyBaseColumn.counter += 1

    # Base a new MaskedColumn class on it.  The normal MaskedColumn
    # hardcodes the initialization to BaseColumn, so we exchange that.
    class MyMaskedColumn(MaskedColumn, Column, MyBaseColumn):
        def __new__(cls, *args, **kwargs):
            self = super().__new__(cls, *args, **kwargs)
            self._baseclass = MyBaseColumn
            return self

    # Creation really needs 2 finalizations (once for the BaseColumn
    # call inside ``__new__`` and once when the view as a MaskedColumn
    # is taken), but since the first is hardcoded, we do not capture it
    # and thus the count is only 1.
    c = MyMaskedColumn([1, 2], mask=[False, True])
    assert MyBaseColumn.counter == 1
    # slicing should need only one ``__array_finalize__`` (used to be 3).
    c0 = c[:]
    assert MyBaseColumn.counter == 2
    # repr should need none (used to be 2!!)
    repr(c0)
    assert MyBaseColumn.counter == 2