def METHOD_NAME(self):
    """Does turning validation on/off work correctly?"""
    # updating shouldn't work if we're validating, too
    self._copy_file(join("files", "test-v0-invalid.ipynb"), "p1.ipynb")
    run_nbgrader(["update", "p1.ipynb"], retcode=1)
    # updating should work, but then validation should fail
    self._copy_file(join("files", "test-v0-invalid.ipynb"), "p1.ipynb")
    run_nbgrader(["update", "p1.ipynb", "--UpdateApp.validate=False"])
    run_nbgrader(["validate", "p1.ipynb"], retcode=1)