def test_view_of_view_modification():
    adata = ad.AnnData(np.zeros((10, 10)))
    adata[0, :][:, 5:].X = np.ones(5)
    assert np.all(adata.X[0, 5:] == np.ones(5))
    adata[[1, 2], :][:, [1, 2]].X = np.ones((2, 2))
    assert np.all(adata.X[1:3, 1:3] == np.ones((2, 2)))

    adata.X = sparse.csr_matrix(adata.X)
    adata[0, :][:, 5:].X = np.ones(5) * 2
    assert np.all(asarray(adata.X)[0, 5:] == np.ones(5) * 2)
    adata[[1, 2], :][:, [1, 2]].X = np.ones((2, 2)) * 2
    assert np.all(asarray(adata.X)[1:3, 1:3] == np.ones((2, 2)) * 2)
def reset_signal_handler(cls, signal_handler):
        """Class state:

        - Overwrites `cls._signal_handler`.
        OS state:
        - Overwrites signal handlers for SIGINT, SIGQUIT, and SIGTERM.

        NB: This method calls signal.signal(), which will crash if not called from the main thread!

        :returns: The :class:`SignalHandler` that was previously registered, or None if this is
                  the first time this method was called.
        """
        assert isinstance(signal_handler, SignalHandler)
        # NB: Modify process-global state!
        for signum, handler in signal_handler.signal_handler_mapping.items():
            signal.signal(signum, handler)
            # Retry any system calls interrupted by any of the signals we just installed handlers for
            # (instead of having them raise EINTR). siginterrupt(3) says this is the default behavior on
            # Linux and OSX.
            signal.siginterrupt(signum, False)

        previous_signal_handler = cls._signal_handler
        # NB: Mutate the class variables!
        cls._signal_handler = signal_handler
        return previous_signal_handler