...
The simplest way to test is with the Postman API Tool
Import the collection
Add an Environment (for example Dev) and add the following Environment Variables:
dialer: specify the http://url of the dialer instance you are using.
campref: the campaign reference you want to use for these tests
It's best to change this every run, so that the dialer doesn't keep state (retry timeout)
extension: the agent extension you are going to use for testing
...