New `fft` tests are failing in CI

[rgommers]

For both NumPy and PyTorch, see for example gh-66. From one CI log:

FAILED array_api_tests/test_fft.py::test_fft - AssertionError: out.dtype=complex128, but should be complex64 [fft(float32)]
Falsifying example: test_fft(
    x=array([0., 0.], dtype=float32),
    data=data(...),
)
Draw 1 (n): None
Draw 2 (axis): 0
Draw 3 (norm): 'ortho'
Draw 4 (kwargs): {'axis': 0, 'norm': 'ortho'}

You can reproduce this example by temporarily adding @reproduce_failure('6.88.4', b'AXicY2BgZGJABYwMAABOAAU=') as a decorator on your test case
FAILED array_api_tests/test_fft.py::test_ifft - AssertionError: out.dtype=complex128, but should be complex64 [ifft(float32)]
Falsifying example: test_ifft(
    x=array([0., 0.], dtype=float32),
    data=data(...),
)
Draw 1 (n): None
Draw 2 (axis): 0
Draw 3 (norm): 'ortho'
Draw 4 (kwargs): {'axis': 0, 'norm': 'ortho'}
Explanation:
    These lines were always and only run by failing examples:
        /home/runner/work/array-api-compat/array-api-compat/array-api-tests/array_api_tests/test_fft.py:91

You can reproduce this example by temporarily adding @reproduce_failure('6.88.4', b'AXicY2BgZGJABYwMAABOAAU=') as a decorator on your test case
FAILED array_api_tests/test_fft.py::test_fftn - AssertionError: out.dtype=complex128, but should be complex64 [fftn(float32)]
Falsifying example: test_fftn(
    x=array([0., 0.], dtype=float32),
    data=data(...),
)
Draw 1 (axes): None
Draw 2 (s): None
Draw 3 (norm): 'ortho'
Draw 4 (kwargs): {'norm': 'ortho'}

You can reproduce this example by temporarily adding @reproduce_failure('6.88.4', b'AXicY2BgZGJABYwMDAAAUwAF') as a decorator on your test case
FAILED array_api_tests/test_fft.py::test_ifftn - AssertionError: out.dtype=complex128, but should be complex64 [ifftn(float32)]
Falsifying example: test_ifftn(
    x=array([0., 0.], dtype=float32),
    data=data(...),
)
Draw 1 (axes): [0]
Draw 2 (s): (1,)
Draw 3 (norm): 'ortho'
Draw 4 (kwargs): {'s': (1,), 'axes': [0], 'norm': 'ortho'}

You can reproduce this example by temporarily adding @reproduce_failure('6.88.4', b'AXicY2BgZGJABoxABAAAUQAG') as a decorator on your test case
FAILED array_api_tests/test_fft.py::test_rfft - ExceptionGroup: Hypothesis found 2 distinct failures. (2 sub-exceptions)
FAILED array_api_tests/test_fft.py::test_irfft - AssertionError: out.dtype=float64, but should be complex64 [irfft(complex64)]
Falsifying example: test_irfft(
    x=array([0.+0.j, 0.+0.j], dtype=complex64),  # or any other generated value
    data=data(...),
)
Draw 1 (n): None
Draw 2 (axis): 0
Draw 3 (norm): 'ortho'
Draw 4 (kwargs): {'axis': 0, 'norm': 'ortho'}

You can reproduce this example by temporarily adding @reproduce_failure('6.88.4', b'AXicY2BkYsAJGBkAAHkABQ==') as a decorator on your test case
FAILED array_api_tests/test_fft.py::test_rfftn - ExceptionGroup: Hypothesis found 2 distinct failures. (2 sub-exceptions)
FAILED array_api_tests/test_fft.py::test_irfftn - AssertionError: out.dtype=float64, but should be complex64 [irfftn(complex64)]
Falsifying example: test_irfftn(
    x=array([0.+0.j, 0.+0.j], dtype=complex64),  # or any other generated value
    data=data(...),
)
Draw 1 (axes): None
Draw 2 (s): None
Draw 3 (norm): 'ortho'
Draw 4 (kwargs): {'norm': 'ortho'}

You can reproduce this example by temporarily adding @reproduce_failure('6.88.4', b'AXicY2BkYsAJGBkYAAB+AAU=') as a decorator on your test case
FAILED array_api_tests/test_fft.py::test_hfft - AssertionError: out.dtype=float64, but should be complex64 [hfft(float32)]
Falsifying example: test_hfft(
    x=array([0., 0.], dtype=float32),  # or any other generated value
    data=data(...),
)
Draw 1 (n): None
Draw 2 (axis): 0
Draw 3 (norm): 'ortho'
Draw 4 (kwargs): {'axis': 0, 'norm': 'ortho'}

You can reproduce this example by temporarily adding @reproduce_failure('6.88.4', b'AXicY2BgZGJABYwMAABOAAU=') as a decorator on your test case
FAILED array_api_tests/test_fft.py::test_ihfft - ExceptionGroup: Hypothesis found 2 distinct failures. (2 sub-exceptions)
= 10 failed, 1003 passed, 85 skipped, 33 xfailed, 2 xpassed, 41102 warnings in 1724.22s (0:28:44) =

That's because data-apis/array-api-tests#196 got merged 4 days ago. @honno could you have a look? If it's not easy to fix, maybe just add a skip for now?

[asmeurer]

Looks like this is the issue @honno discussed the other day where numpy doesn't actually implement complex64. So we need to add wrappers to manually downcast. If we need to release before this is fixed we can skip these tests or pin the test suite to the previous release for now.

[asmeurer]

FFT tests should all be working now. We have to XFAIL some cupy ones because of (apparent) cupy bugs (#78 (comment)), and they are skipped for dask, but otherwise fft is all working now, and CI is passing.