def test_cast_signed_to_unsigned():
    safe_cases = [
        (np.array([0, 1, 2, 3], dtype='i1'), pa.uint8(),
         np.array([0, 1, 2, 3], dtype='u1'), pa.uint8()),
        (np.array([0, 1, 2, 3], dtype='i2'), pa.uint16(),
         np.array([0, 1, 2, 3], dtype='u2'), pa.uint16())
    ]

    for case in safe_cases:
        _check_cast_case(case)

def test_cast_integers_unsafe():
    # We let NumPy do the unsafe casting
    unsafe_cases = [
        (np.array([50000], dtype='i4'), 'int32',
         np.array([50000], dtype='i2'), pa.int16()),
        (np.array([70000], dtype='i4'), 'int32',
         np.array([70000], dtype='u2'), pa.uint16()),
        (np.array([-1], dtype='i4'), 'int32',
         np.array([-1], dtype='u2'), pa.uint16()),
        (np.array([50000], dtype='u2'), pa.uint16(),
         np.array([50000], dtype='i2'), pa.int16())
    ]

    for case in unsafe_cases:
        _check_cast_case(case, safe=False)

def _from_jvm_int_type(jvm_type):
    """
    Convert a JVM int type to its Python equivalent.

    Parameters
    ----------
    jvm_type: org.apache.arrow.vector.types.pojo.ArrowType$Int

    Returns
    -------
    typ: pyarrow.DataType
    """
    if jvm_type.isSigned:
        if jvm_type.bitWidth == 8:
            return pa.int8()
        elif jvm_type.bitWidth == 16:
            return pa.int16()
        elif jvm_type.bitWidth == 32:
            return pa.int32()
        elif jvm_type.bitWidth == 64:
            return pa.int64()
    else:
        if jvm_type.bitWidth == 8:
            return pa.uint8()
        elif jvm_type.bitWidth == 16:
            return pa.uint16()
        elif jvm_type.bitWidth == 32:
            return pa.uint32()
        elif jvm_type.bitWidth == 64:
            return pa.uint64()

def test_cast_integers_safe():
    safe_cases = [
        (np.array([0, 1, 2, 3], dtype='i1'), 'int8',
         np.array([0, 1, 2, 3], dtype='i4'), pa.int32()),
        (np.array([0, 1, 2, 3], dtype='i1'), 'int8',
         np.array([0, 1, 2, 3], dtype='u4'), pa.uint16()),
        (np.array([0, 1, 2, 3], dtype='i1'), 'int8',
         np.array([0, 1, 2, 3], dtype='u1'), pa.uint8()),
        (np.array([0, 1, 2, 3], dtype='i1'), 'int8',
         np.array([0, 1, 2, 3], dtype='f8'), pa.float64())
    ]

    for case in safe_cases:
        _check_cast_case(case)

    unsafe_cases = [
        (np.array([50000], dtype='i4'), 'int32', 'int16'),
        (np.array([70000], dtype='i4'), 'int32', 'uint16'),
        (np.array([-1], dtype='i4'), 'int32', 'uint16'),
        (np.array([50000], dtype='u2'), 'uint16', 'int16')
    ]
    for in_data, in_type, out_type in unsafe_cases:
        in_arr = pa.array(in_data, type=in_type)

        with pytest.raises(pa.ArrowInvalid):
            in_arr.cast(out_type)

def test_type_to_pandas_dtype():
    M8_ns = np.dtype('datetime64[ns]')
    cases = [
        (pa.null(), np.float64),
        (pa.bool_(), np.bool_),
        (pa.int8(), np.int8),
        (pa.int16(), np.int16),
        (pa.int32(), np.int32),
        (pa.int64(), np.int64),
        (pa.uint8(), np.uint8),
        (pa.uint16(), np.uint16),
        (pa.uint32(), np.uint32),
        (pa.uint64(), np.uint64),
        (pa.float16(), np.float16),
        (pa.float32(), np.float32),
        (pa.float64(), np.float64),
        (pa.date32(), M8_ns),
        (pa.date64(), M8_ns),
        (pa.timestamp('ms'), M8_ns),
        (pa.binary(), np.object_),
        (pa.binary(12), np.object_),
        (pa.string(), np.object_),
        (pa.list_(pa.int8()), np.object_),
    ]
    for arrow_type, numpy_type in cases:
        assert arrow_type.to_pandas_dtype() == numpy_type

def test_empty_cast():
    types = [
        pa.null(),
        pa.bool_(),
        pa.int8(),
        pa.int16(),
        pa.int32(),
        pa.int64(),
        pa.uint8(),
        pa.uint16(),
        pa.uint32(),
        pa.uint64(),
        pa.float16(),
        pa.float32(),
        pa.float64(),
        pa.date32(),
        pa.date64(),
        pa.binary(),
        pa.binary(length=4),
        pa.string(),
    ]

    for (t1, t2) in itertools.product(types, types):
        try:
            # ARROW-4766: Ensure that supported types conversion don't segfault
            # on empty arrays of common types
            pa.array([], type=t1).cast(t2)
        except pa.lib.ArrowNotImplementedError:
            continue

def dataframe_with_arrays(include_index=False):
    """
    Dataframe with numpy arrays columns of every possible primtive type.

    Returns
    -------
    df: pandas.DataFrame
    schema: pyarrow.Schema
        Arrow schema definition that is in line with the constructed df.
    """
    dtypes = [('i1', pa.int8()), ('i2', pa.int16()),
              ('i4', pa.int32()), ('i8', pa.int64()),
              ('u1', pa.uint8()), ('u2', pa.uint16()),
              ('u4', pa.uint32()), ('u8', pa.uint64()),
              ('f4', pa.float32()), ('f8', pa.float64())]

    arrays = OrderedDict()
    fields = []
    for dtype, arrow_dtype in dtypes:
        fields.append(pa.field(dtype, pa.list_(arrow_dtype)))
        arrays[dtype] = [
            np.arange(10, dtype=dtype),
            np.arange(5, dtype=dtype),
            None,
            np.arange(1, dtype=dtype)
        ]

    fields.append(pa.field('str', pa.list_(pa.string())))
    arrays['str'] = [
        np.array([u"1", u"ä"], dtype="object"),
        None,
        np.array([u"1"], dtype="object"),
        np.array([u"1", u"2", u"3"], dtype="object")
    ]

    fields.append(pa.field('datetime64', pa.list_(pa.timestamp('ms'))))
    arrays['datetime64'] = [
        np.array(['2007-07-13T01:23:34.123456789',
                  None,
                  '2010-08-13T05:46:57.437699912'],
                 dtype='datetime64[ms]'),
        None,
        None,
        np.array(['2007-07-13T02',
                  None,
                  '2010-08-13T05:46:57.437699912'],
                 dtype='datetime64[ms]'),
    ]

    if include_index:
        fields.append(pa.field('__index_level_0__', pa.int64()))
    df = pd.DataFrame(arrays)
    schema = pa.schema(fields)

    return df, schema

def test_type_for_alias():
    cases = [
        ('i1', pa.int8()),
        ('int8', pa.int8()),
        ('i2', pa.int16()),
        ('int16', pa.int16()),
        ('i4', pa.int32()),
        ('int32', pa.int32()),
        ('i8', pa.int64()),
        ('int64', pa.int64()),
        ('u1', pa.uint8()),
        ('uint8', pa.uint8()),
        ('u2', pa.uint16()),
        ('uint16', pa.uint16()),
        ('u4', pa.uint32()),
        ('uint32', pa.uint32()),
        ('u8', pa.uint64()),
        ('uint64', pa.uint64()),
        ('f4', pa.float32()),
        ('float32', pa.float32()),
        ('f8', pa.float64()),
        ('float64', pa.float64()),
        ('date32', pa.date32()),
        ('date64', pa.date64()),
        ('string', pa.string()),
        ('str', pa.string()),
        ('binary', pa.binary()),
        ('time32[s]', pa.time32('s')),
        ('time32[ms]', pa.time32('ms')),
        ('time64[us]', pa.time64('us')),
        ('time64[ns]', pa.time64('ns')),
        ('timestamp[s]', pa.timestamp('s')),
        ('timestamp[ms]', pa.timestamp('ms')),
        ('timestamp[us]', pa.timestamp('us')),
        ('timestamp[ns]', pa.timestamp('ns')),
    ]

    for val, expected in cases:
        assert pa.type_for_alias(val) == expected

def test_table_from_lists_raises():
    data = [
        list(range(5)),
        [-10, -5, 0, 5, 10]
    ]

    with pytest.raises(TypeError):
        pa.Table.from_arrays(data, names=['a', 'b'])

    schema = pa.schema([
        pa.field('a', pa.uint16()),
        pa.field('b', pa.int64())
    ])
    with pytest.raises(TypeError):
        pa.Table.from_arrays(data, schema=schema)

def test_is_integer():
    signed_ints = [pa.int8(), pa.int16(), pa.int32(), pa.int64()]
    unsigned_ints = [pa.uint8(), pa.uint16(), pa.uint32(), pa.uint64()]

    for t in signed_ints + unsigned_ints:
        assert types.is_integer(t)

    for t in signed_ints:
        assert types.is_signed_integer(t)
        assert not types.is_unsigned_integer(t)

    for t in unsigned_ints:
        assert types.is_unsigned_integer(t)
        assert not types.is_signed_integer(t)

    assert not types.is_integer(pa.float32())
    assert not types.is_signed_integer(pa.float32())

    def test_integer_no_nulls(self):
        data = {}
        fields = []

        numpy_dtypes = [('i1', A.int8()), ('i2', A.int16()),
                        ('i4', A.int32()), ('i8', A.int64()),
                        ('u1', A.uint8()), ('u2', A.uint16()),
                        ('u4', A.uint32()), ('u8', A.uint64())]
        num_values = 100

        for dtype, arrow_dtype in numpy_dtypes:
            info = np.iinfo(dtype)
            values = np.random.randint(info.min,
                                       min(info.max, np.iinfo('i8').max),
                                       size=num_values)
            data[dtype] = values.astype(dtype)
            fields.append(A.Field.from_py(dtype, arrow_dtype))

        df = pd.DataFrame(data)
        schema = A.Schema.from_fields(fields)
        self._check_pandas_roundtrip(df, expected_schema=schema)

def test_from_numpy_dtype():
    cases = [
        (np.dtype('bool'), pa.bool_()),
        (np.dtype('int8'), pa.int8()),
        (np.dtype('int16'), pa.int16()),
        (np.dtype('int32'), pa.int32()),
        (np.dtype('int64'), pa.int64()),
        (np.dtype('uint8'), pa.uint8()),
        (np.dtype('uint16'), pa.uint16()),
        (np.dtype('uint32'), pa.uint32()),
        (np.dtype('float16'), pa.float16()),
        (np.dtype('float32'), pa.float32()),
        (np.dtype('float64'), pa.float64()),
        (np.dtype('U'), pa.string()),
        (np.dtype('S'), pa.binary()),
        (np.dtype('datetime64[s]'), pa.timestamp('s')),
        (np.dtype('datetime64[ms]'), pa.timestamp('ms')),
        (np.dtype('datetime64[us]'), pa.timestamp('us')),
        (np.dtype('datetime64[ns]'), pa.timestamp('ns'))
    ]

    for dt, pt in cases:
        result = pa.from_numpy_dtype(dt)
        assert result == pt

    # Things convertible to numpy dtypes work
    assert pa.from_numpy_dtype('U') == pa.string()
    assert pa.from_numpy_dtype(np.unicode) == pa.string()
    assert pa.from_numpy_dtype('int32') == pa.int32()
    assert pa.from_numpy_dtype(bool) == pa.bool_()

    with pytest.raises(NotImplementedError):
        pa.from_numpy_dtype(np.dtype('O'))

    with pytest.raises(TypeError):
        pa.from_numpy_dtype('not_convertible_to_dtype')

    def test_integer_no_nulls(self):
        data = OrderedDict()
        fields = []

        numpy_dtypes = [
            ('i1', pa.int8()), ('i2', pa.int16()),
            ('i4', pa.int32()), ('i8', pa.int64()),
            ('u1', pa.uint8()), ('u2', pa.uint16()),
            ('u4', pa.uint32()), ('u8', pa.uint64()),
            ('longlong', pa.int64()), ('ulonglong', pa.uint64())
        ]
        num_values = 100

        for dtype, arrow_dtype in numpy_dtypes:
            info = np.iinfo(dtype)
            values = np.random.randint(max(info.min, np.iinfo(np.int_).min),
                                       min(info.max, np.iinfo(np.int_).max),
                                       size=num_values)
            data[dtype] = values.astype(dtype)
            fields.append(pa.field(dtype, arrow_dtype))

        df = pd.DataFrame(data)
        schema = pa.schema(fields)
        self._check_pandas_roundtrip(df, expected_schema=schema)

    array = pa.array(data, type=typ)
    result = pickle.loads(pickle.dumps(array))
    assert array.equals(result)


@pytest.mark.parametrize(
    ('type', 'expected'),
    [
        (pa.null(), 'empty'),
        (pa.bool_(), 'bool'),
        (pa.int8(), 'int8'),
        (pa.int16(), 'int16'),
        (pa.int32(), 'int32'),
        (pa.int64(), 'int64'),
        (pa.uint8(), 'uint8'),
        (pa.uint16(), 'uint16'),
        (pa.uint32(), 'uint32'),
        (pa.uint64(), 'uint64'),
        (pa.float16(), 'float16'),
        (pa.float32(), 'float32'),
        (pa.float64(), 'float64'),
        (pa.date32(), 'date'),
        (pa.date64(), 'date'),
        (pa.binary(), 'bytes'),
        (pa.binary(length=4), 'bytes'),
        (pa.string(), 'unicode'),
        (pa.list_(pa.list_(pa.int16())), 'list[list[int16]]'),
        (pa.decimal128(18, 3), 'decimal'),
        (pa.timestamp('ms'), 'datetime'),
        (pa.timestamp('us', 'UTC'), 'datetimetz'),
        (pa.time32('s'), 'time'),

import collections
import datetime
import decimal
import itertools
import numpy as np
import six
import pytz


int_type_pairs = [
    (np.int8, pa.int8()),
    (np.int16, pa.int16()),
    (np.int32, pa.int32()),
    (np.int64, pa.int64()),
    (np.uint8, pa.uint8()),
    (np.uint16, pa.uint16()),
    (np.uint32, pa.uint32()),
    (np.uint64, pa.uint64())]


np_int_types, _ = zip(*int_type_pairs)


class StrangeIterable:
    def __init__(self, lst):
        self.lst = lst

    def __iter__(self):
        return self.lst.__iter__()

    assert not tensor.is_mutable

def test_tensor_base_object():
    tensor = pa.Tensor.from_numpy(np.random.randn(10, 4))
    n = sys.getrefcount(tensor)
    array = tensor.to_numpy()
    assert sys.getrefcount(tensor) == n + 1


@pytest.mark.parametrize('dtype_str,arrow_type', [
    ('i1', pa.int8()),
    ('i2', pa.int16()),
    ('i4', pa.int32()),
    ('i8', pa.int64()),
    ('u1', pa.uint8()),
    ('u2', pa.uint16()),
    ('u4', pa.uint32()),
    ('u8', pa.uint64()),
    ('f2', pa.float16()),
    ('f4', pa.float32()),
    ('f8', pa.float64())
])
def test_tensor_numpy_roundtrip(dtype_str, arrow_type):
    dtype = np.dtype(dtype_str)
    data = (100 * np.random.randn(10, 4)).astype(dtype)

    tensor = pa.Tensor.from_numpy(data)
    assert tensor.type == arrow_type

    repr(tensor)

# without to invoke the JVM.
#
# The specifications were created using:
#
#   om = jpype.JClass('com.fasterxml.jackson.databind.ObjectMapper')()
#   field = …  # Code to instantiate the field
#   jvm_spec = om.writeValueAsString(field)
@pytest.mark.parametrize('pa_type,jvm_spec', [
    (pa.null(), '{"name":"null"}'),
    (pa.bool_(), '{"name":"bool"}'),
    (pa.int8(), '{"name":"int","bitWidth":8,"isSigned":true}'),
    (pa.int16(), '{"name":"int","bitWidth":16,"isSigned":true}'),
    (pa.int32(), '{"name":"int","bitWidth":32,"isSigned":true}'),
    (pa.int64(), '{"name":"int","bitWidth":64,"isSigned":true}'),
    (pa.uint8(), '{"name":"int","bitWidth":8,"isSigned":false}'),
    (pa.uint16(), '{"name":"int","bitWidth":16,"isSigned":false}'),
    (pa.uint32(), '{"name":"int","bitWidth":32,"isSigned":false}'),
    (pa.uint64(), '{"name":"int","bitWidth":64,"isSigned":false}'),
    (pa.float16(), '{"name":"floatingpoint","precision":"HALF"}'),
    (pa.float32(), '{"name":"floatingpoint","precision":"SINGLE"}'),
    (pa.float64(), '{"name":"floatingpoint","precision":"DOUBLE"}'),
    (pa.time32('s'), '{"name":"time","unit":"SECOND","bitWidth":32}'),
    (pa.time32('ms'), '{"name":"time","unit":"MILLISECOND","bitWidth":32}'),
    (pa.time64('us'), '{"name":"time","unit":"MICROSECOND","bitWidth":64}'),
    (pa.time64('ns'), '{"name":"time","unit":"NANOSECOND","bitWidth":64}'),
    (pa.timestamp('s'), '{"name":"timestamp","unit":"SECOND",'
        '"timezone":null}'),
    (pa.timestamp('ms'), '{"name":"timestamp","unit":"MILLISECOND",'
        '"timezone":null}'),
    (pa.timestamp('us'), '{"name":"timestamp","unit":"MICROSECOND",'
        '"timezone":null}'),

                   pa.field('b', pa.int8()),
                   pa.field('c', pa.string())])
    ]

    in_dict = {}
    for i, type_ in enumerate(types):
        assert hash(type_) == hash(type_)
        in_dict[type_] = i
        assert in_dict[type_] == i


@pytest.mark.parametrize('t,check_func', [
    (pa.date32(), types.is_date32),
    (pa.date64(), types.is_date64),
    (pa.time32('s'), types.is_time32),
    (pa.time64('ns'), types.is_time64),
    (pa.int8(), types.is_int8),
    (pa.int16(), types.is_int16),
    (pa.int32(), types.is_int32),
    (pa.int64(), types.is_int64),
    (pa.uint8(), types.is_uint8),
    (pa.uint16(), types.is_uint16),
    (pa.uint32(), types.is_uint32),
    (pa.uint64(), types.is_uint64),
    (pa.float16(), types.is_float16),
    (pa.float32(), types.is_float32),
    (pa.float64(), types.is_float64)
])
def test_exact_primitive_types(t, check_func):
    assert check_func(t)

null_type = st.just(pa.null())
bool_type = st.just(pa.bool_())

binary_type = st.just(pa.binary())
string_type = st.just(pa.string())

signed_integer_types = st.sampled_from([
    pa.int8(),
    pa.int16(),
    pa.int32(),
    pa.int64()
])
unsigned_integer_types = st.sampled_from([
    pa.uint8(),
    pa.uint16(),
    pa.uint32(),
    pa.uint64()
])
integer_types = st.one_of(signed_integer_types, unsigned_integer_types)

floating_types = st.sampled_from([
    pa.float16(),
    pa.float32(),
    pa.float64()
])
decimal_type = st.builds(
    pa.decimal128,
    precision=st.integers(min_value=1, max_value=38),
    scale=st.integers(min_value=1, max_value=38)
)