def test_simple_sum(self):
t1 = Tensor([1, 2, 3], requires_grad=True)
t2 = t1.sum()
t2.backward()
assert t1.grad.data.tolist() == [1, 1, 1]
def test_sum_with_grad(self):
t1 = Tensor([1, 2, 3], requires_grad=True)
t2 = t1.sum()
t2.backward(Tensor(3))
assert t1.grad.data.tolist() == [3, 3, 3]