def testNoOtherGradients(self):
    """Tests no gradient propagates through things other than v_tm1."""
    # Gradients are only defined for v_tm1, not any other input.
    gradients = tf.gradients([self.loss_op],
                             [self.q_t, self.r_t, self.pcont_t])
    self.assertEqual(gradients, [None] * len(gradients))
Tests no gradient propagates through things other than v_tm1.
trfl/value_ops_test.py