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 _make_proxy(self, key, match):
        proxy_type = match.group("type")
        key = match.group("key").strip()
        if proxy_type == "env":
            proxy = EnvProxy(key)
        else:
            proxy = ResolverMethodProxy(self._resolver, proxy_type, key)
        filters = [f for f in [rf.strip() for rf in match.group("filters").split("|")] if f]
        for filter_name in filters:
            if filter_name == "jsondecode":
                proxy = JSONDecodeFilter(proxy)
            elif filter_name == "base64decode":
                proxy = Base64DecodeFilter(proxy)
            elif filter_name.startswith("element:"):
                key = filter_name.split(":", 1)[-1]
                proxy = ElementFilter(key, proxy)
            else:
                raise ValueError("Unknown filter %s", filter_name)
        return proxy