There is a service called Requestb.in that will allow you to test the Webhook. It's easy to do.
To set up Requestb.in:
1. Go to http://requestb.in
2. Click on create a request bin
3. Copy the URL from request.in
4. Sign in to DocVerify
5. Click on "My Account"
6. Click the "API" tab
7. Enter the requestb.in in the Webhook URL textbox
8. Click Update
After you run a few tests, go back to the Requestb.in page, and refresh it. It should show all of the updates.