How can i test my symfony Application

After more than 15 days i have finished developing my new symfony application , now I wanted to test it , and I kinda lost concerning. So my questions for you php GEEK are the following :

1- What are the frameworks that i can use to test my php app?

2- can someone specify step by step how can I manage to test my app?

3- What kind of test could I made other than the Unit test?

4- How can I made the unit test step by step please (separating the database and the external ressources...), in another word what is the correct way to use integration tests in my build process?

Thnak you in advance.