def test_view_of_view(matrix_type, subset_func, subset_func2):
    adata = gen_adata((30, 15), X_type=matrix_type)
    adata.raw = adata
    if subset_func is single_subset:
        pytest.xfail("Other subset generating functions have trouble with this")
    var_s1 = subset_func(adata.var_names, min_size=4)
    var_view1 = adata[:, var_s1]
    var_s2 = subset_func2(var_view1.var_names)
    var_view2 = var_view1[:, var_s2]
    assert var_view2._adata_ref is adata
    obs_s1 = subset_func(adata.obs_names, min_size=4)
    obs_view1 = adata[obs_s1, :]
    obs_s2 = subset_func2(obs_view1.obs_names)
    assert adata[obs_s1, :][:, var_s1][obs_s2, :]._adata_ref is adata

    view_of_actual_copy = adata[:, var_s1].copy()[obs_s1, :].copy()[:, var_s2].copy()

    view_of_view_copy = adata[:, var_s1][obs_s1, :][:, var_s2].copy()

    assert_equal(view_of_actual_copy, view_of_view_copy, exact=True)
def wait_for_snapshot_status(self, snapshot_id, status):
        """Waits for a Snapshot to reach a given status."""
        start_time = time.time()
        old_value = value = self._get_snapshot_status(snapshot_id)
        while True:
            dtime = time.time() - start_time
            time.sleep(self.build_interval)
            if value != old_value:
                LOG.info('Value transition from "%s" to "%s"'
                         'in %d second(s).', old_value,
                         value, dtime)
            if (value == status):
                return value

            if dtime > self.build_timeout:
                message = ('Time Limit Exceeded! (%ds)'
                           'while waiting for %s, '
                           'but we got %s.' %
                           (self.build_timeout, status, value))
                raise exceptions.TimeoutException(message)
            time.sleep(self.build_interval)
            old_value = value
            value = self._get_snapshot_status(snapshot_id)