def test_layers_view():
    X = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
    L = np.array([[10, 11, 12], [13, 14, 15], [16, 17, 18]])
    real_adata = ad.AnnData(X)
    real_adata.layers["L"] = L
    view_adata = real_adata[1:, 1:]
    real_hash = joblib.hash(real_adata)
    view_hash = joblib.hash(view_adata)

    assert view_adata.is_view

    with pytest.raises(ValueError):
        view_adata.layers["L2"] = L + 2

    assert view_adata.is_view  # Failing to set layer item makes adata not view
    assert real_hash == joblib.hash(real_adata)
    assert view_hash == joblib.hash(view_adata)

    view_adata.layers["L2"] = L[1:, 1:] + 2

    assert not view_adata.is_view
    assert real_hash == joblib.hash(real_adata)
    assert view_hash != joblib.hash(view_adata)
def _exit_with_failure(cls, terminal_msg):
        timestamp_msg = (
            f"timestamp: {cls._iso_timestamp_for_now()}\n"
            if cls._should_print_backtrace_to_terminal
            else ""
        )
        details_msg = (
            ""
            if cls._should_print_backtrace_to_terminal
            else "\n\n(Use --print-exception-stacktrace to see more error details.)"
        )
        terminal_msg = terminal_msg or "<no exit reason provided>"
        formatted_terminal_msg = cls._EXIT_FAILURE_TERMINAL_MESSAGE_FORMAT.format(
            timestamp_msg=timestamp_msg, terminal_msg=terminal_msg, details_msg=details_msg
        )
        # Exit with failure, printing a message to the terminal (or whatever the interactive stream is).
        cls._exiter.exit_and_fail(msg=formatted_terminal_msg, out=cls._interactive_output_stream)