test scatter_add_ and index_add_ safety checks

test.py

import torch

def test_index_add(cuda):
    a = torch.ones(5)
    b = torch.ones(5)
    i = torch.ones(5).long()
    if cuda:
        a = a.cuda()
        b = b.cuda()
        i = i.cuda()
    a.index_add_(0, i, b)  # should not errorn
    print("OK")
    a.index_add_(0, i, a)  # should error
    print("not OK")

def test_scatter_add(cuda):
    a = torch.ones(5)
    b = torch.ones(5)
    i = torch.ones(5).long()
    if cuda:
        a = a.cuda()
        b = b.cuda()
        i = i.cuda()
    a.scatter_add_(0, i, b)  # should not error
    print("OK")
    a.scatter_add_(0, i, a)  # should error
    print("not OK")

test_index_add(True)
test_index_add(False)
test_scatter_add(True)
test_scatter_add(False)