def testInvalidTypeTau(self):
    """Tests error when tau has wrong type."""
    target_variables = [tf.Variable(tf.random_normal(shape=[1, 2]))]
    source_variables = [tf.Variable(tf.random_normal(shape=[1, 2]))]
    self.assertRaises(TypeError, target_update_ops.update_target_variables,
                      target_variables, source_variables, 1)
Tests error when tau has wrong type.
trfl/target_update_ops_test.py