Add functional tests for correct form submission
Add functional tests for correct form submission

- Test that correct error messages are raised
- Tests that the form is replaced with success text successfully

kevgathuku/compshop,andela-kndungu/compshop,kevgathuku/compshop,kevgathuku/compshop,andela-kndungu/compshop,kevgathuku/compshop,andela-kndungu/compshop,andela-kndungu/compshop