How to automate my testing that connects (and modifys) to an external server

I'm currently writing a Java program that is an interface to another server. The majority of the functions (close to >90%) do something on the server. Currently, I'm just writing simple classes that run some actions on the server, and then check it myself, or add methods to the test that read back the written information.

Currently, I'm developing on my own computer, and have a version of the server running locally on a VM.

I don't want to continually run the tests at every build, as I don't want to keep modifying the server I am connected too. I am not sure the best way to go about my testing. I have my JUnit tests (on simple functions that do not interact externally) that run every build. I can't seem to see the set way in JUnit to write tests that do not have to run at every build (perhaps when their functions change?).

Or, can anyone point me in the correct direction of how to best handle my testing.

Thanks!