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"""
Test scalar buffer interface adheres to PEP 3118
"""
import numpy as np
from numpy.core._rational_tests import rational
from numpy.core._multiarray_tests import get_buffer_info
import pytest
from numpy.testing import assert_, assert_equal, assert_raises
# PEP3118 format strings for native (standard alignment and byteorder) types
scalars_and_codes = [
(np.bool_, '?'),
(np.byte, 'b'),
(np.short, 'h'),
(np.intc, 'i'),
(np.int_, 'l'),
(np.longlong, 'q'),
(np.ubyte, 'B'),
(np.ushort, 'H'),
(np.uintc, 'I'),
(np.uint, 'L'),
(np.ulonglong, 'Q'),
(np.half, 'e'),
(np.single, 'f'),
(np.double, 'd'),
(np.longdouble, 'g'),
(np.csingle, 'Zf'),
(np.cdouble, 'Zd'),
(np.clongdouble, 'Zg'),
]
scalars_only, codes_only = zip(*scalars_and_codes)
class TestScalarPEP3118:
@pytest.mark.parametrize('scalar', scalars_only, ids=codes_only)
def test_scalar_match_array(self, scalar):
x = scalar()
a = np.array([], dtype=np.dtype(scalar))
mv_x = memoryview(x)
mv_a = memoryview(a)
assert_equal(mv_x.format, mv_a.format)
@pytest.mark.parametrize('scalar', scalars_only, ids=codes_only)
def test_scalar_dim(self, scalar):
x = scalar()
mv_x = memoryview(x)
assert_equal(mv_x.itemsize, np.dtype(scalar).itemsize)
assert_equal(mv_x.ndim, 0)
assert_equal(mv_x.shape, ())
assert_equal(mv_x.strides, ())
assert_equal(mv_x.suboffsets, ())
@pytest.mark.parametrize('scalar, code', scalars_and_codes, ids=codes_only)
def test_scalar_code_and_properties(self, scalar, code):
x = scalar()
expected = dict(strides=(), itemsize=x.dtype.itemsize, ndim=0,
shape=(), format=code, readonly=True)
mv_x = memoryview(x)
assert self._as_dict(mv_x) == expected
@pytest.mark.parametrize('scalar', scalars_only, ids=codes_only)
def test_scalar_buffers_readonly(self, scalar):
x = scalar()
with pytest.raises(BufferError, match="scalar buffer is readonly"):
get_buffer_info(x, ["WRITABLE"])
def test_void_scalar_structured_data(self):
dt = np.dtype([('name', np.str_, 16), ('grades', np.float64, (2,))])
x = np.array(('ndarray_scalar', (1.2, 3.0)), dtype=dt)[()]
assert_(isinstance(x, np.void))
mv_x = memoryview(x)
expected_size = 16 * np.dtype((np.str_, 1)).itemsize
expected_size += 2 * np.dtype(np.float64).itemsize
assert_equal(mv_x.itemsize, expected_size)
assert_equal(mv_x.ndim, 0)
assert_equal(mv_x.shape, ())
assert_equal(mv_x.strides, ())
assert_equal(mv_x.suboffsets, ())
# check scalar format string against ndarray format string
a = np.array([('Sarah', (8.0, 7.0)), ('John', (6.0, 7.0))], dtype=dt)
assert_(isinstance(a, np.ndarray))
mv_a = memoryview(a)
assert_equal(mv_x.itemsize, mv_a.itemsize)
assert_equal(mv_x.format, mv_a.format)
# Check that we do not allow writeable buffer export (technically
# we could allow it sometimes here...)
with pytest.raises(BufferError, match="scalar buffer is readonly"):
get_buffer_info(x, ["WRITABLE"])
def _as_dict(self, m):
return dict(strides=m.strides, shape=m.shape, itemsize=m.itemsize,
ndim=m.ndim, format=m.format, readonly=m.readonly)
def test_datetime_memoryview(self):
# gh-11656
# Values verified with v1.13.3, shape is not () as in test_scalar_dim
dt1 = np.datetime64('2016-01-01')
dt2 = np.datetime64('2017-01-01')
expected = dict(strides=(1,), itemsize=1, ndim=1, shape=(8,),
format='B', readonly=True)
v = memoryview(dt1)
assert self._as_dict(v) == expected
v = memoryview(dt2 - dt1)
assert self._as_dict(v) == expected
dt = np.dtype([('a', 'uint16'), ('b', 'M8[s]')])
a = np.empty(1, dt)
# Fails to create a PEP 3118 valid buffer
assert_raises((ValueError, BufferError), memoryview, a[0])
# Check that we do not allow writeable buffer export
with pytest.raises(BufferError, match="scalar buffer is readonly"):
get_buffer_info(dt1, ["WRITABLE"])
@pytest.mark.parametrize('s', [
pytest.param("\x32\x32", id="ascii"),
pytest.param("\uFE0F\uFE0F", id="basic multilingual"),
pytest.param("\U0001f4bb\U0001f4bb", id="non-BMP"),
])
def test_str_ucs4(self, s):
s = np.str_(s) # only our subclass implements the buffer protocol
# all the same, characters always encode as ucs4
expected = dict(strides=(), itemsize=8, ndim=0, shape=(), format='2w',
readonly=True)
v = memoryview(s)
assert self._as_dict(v) == expected
# integers of the paltform-appropriate endianness
code_points = np.frombuffer(v, dtype='i4')
assert_equal(code_points, [ord(c) for c in s])
# Check that we do not allow writeable buffer export
with pytest.raises(BufferError, match="scalar buffer is readonly"):
get_buffer_info(s, ["WRITABLE"])
def test_user_scalar_fails_buffer(self):
r = rational(1)
with assert_raises(TypeError):
memoryview(r)
# Check that we do not allow writeable buffer export
with pytest.raises(BufferError, match="scalar buffer is readonly"):
get_buffer_info(r, ["WRITABLE"])
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