I am working on spring boot application. I have to write test cases for it. I haven't written test cases before, so someone suggested using spock framework for it. I explored spock and i think it is more related to groovy language.
Can i write spock test cases for my spring application?
If so then could you suggest me a better documentation of "how to use it with spring boot application"?
Yes, you can write spock test cases for your spring application.
Look at the official documentation for an example of Spock testing with Spring Boot
A simple google search reveals a basic example of Using Spock to test Spring classes.
Spring One g2x has a large presentation on Testing Java, Groovy, Spring and Web Applications with Spock.
Groovy and Java can freely be mixed together you can use any Java based library you like, or use Groovy based libraries.