Usage of the word help

Please help me with the following sentences:

1. The training was really useful. It will help us testing the product.

vs

2. The training was really useful. It will help us test the product.

vs

3. The training was really useful. It will help us in testing the product.

I think the preposition "in" used in the third sentence is really redundant. What is the type of the verb when it is used like verb + object + verb?

I mean if you compare it with make clause make + object + verb/adjective, example, She made me do the murder.

Please advise!

Thanks,
Harry