def test_deepcopy_subset(adata, spmat: type):
    adata.obsp["arr"] = np.zeros((adata.n_obs, adata.n_obs))
    adata.obsp["spmat"] = spmat((adata.n_obs, adata.n_obs))

    adata = deepcopy(adata[:10].copy())

    assert isinstance(adata.obsp["arr"], np.ndarray)
    assert not isinstance(adata.obsp["arr"], ArrayView)
    np.testing.assert_array_equal(adata.obsp["arr"].shape, (10, 10))

    assert isinstance(adata.obsp["spmat"], spmat)
    assert not isinstance(
        adata.obsp["spmat"],
        SparseCSRView if spmat is sparse.csr_matrix else SparseCSCView,
    )
    np.testing.assert_array_equal(adata.obsp["spmat"].shape, (10, 10))
def _testrefastpath(repat):
    """Test if a re pattern can use fast path.

    That is, for every "$A/$B" path the pattern matches, "$A" must also be
    matched,

    Return True if we're sure it is. Return False otherwise.
    """
    # XXX: It's very hard to implement this. These are what need to be
    # supported in production and tests. Very hacky. But we plan to get rid
    # of re matchers eventually.

    # Rules like "(?!experimental/)"
    if repat.startswith("(?!") and repat.endswith(")") and repat.count(")") == 1:
        return True

    # Rules used in doctest
    if repat == "(i|j)$":
        return True

    return False