base.py 文件源码

def setUpClass(klass):
        """
        In order for tests to pass on Travis-CI we must use the 'Agg'
        matplotlib backend. This setup function ensures that all tests
        that do visual work setup the backend correctly.

        Note:
        """
        klass._backend = mpl.get_backend()
        super(VisualTestCase, klass).setUpClass()