def test_drop_obs_column():
    adata = ad.AnnData(np.array(X_list), obs=obs_dict, dtype="int32")

    subset = adata[:2]
    assert subset.is_view
    # returns a copy of obs
    assert subset.obs.drop(columns=["oanno1"]).columns.tolist() == ["oanno2", "oanno3"]
    assert subset.is_view
    # would modify obs, so it should actualize subset and not modify adata
    subset.obs.drop(columns=["oanno1"], inplace=True)
    assert not subset.is_view
    assert subset.obs.columns.tolist() == ["oanno2", "oanno3"]

    assert adata.obs.columns.tolist() == ["oanno1", "oanno2", "oanno3"]
def rename_source(self):
        """This is fairly horrible.
        The github tarfiles have weird names that do not correspond to the
        canonical name. We need to rename these, but leave a symlink for
        spack to work with.
        """
        # Note that this particular OpenFOAM requires absolute directories
        # to build correctly!
        parent   = os.path.dirname(self.stage.source_path)
        original = os.path.basename(self.stage.source_path)
        target   = 'OpenFOAM-{0}'.format(self.version)
        # Could also grep through etc/bashrc for WM_PROJECT_VERSION
        with working_dir(parent):
            if original != target and not os.path.lexists(target):
                os.rename(original, target)
                os.symlink(target, original)
                tty.info('renamed {0} -> {1}'.format(original, target))