test/postman#8 Functions Endpoints

Make Test to all the endpoints to see if the responses are correct and it function correctly.

• GET: 'functions/', 'functions/:id'
• POST: 'functions/'
• PUT: 'functions/:id'
• PATCH: 'functions/:id'
• DELETE: 'functions/:id'

Later of this save all the tests and add it to the repo those files.