Build taking too long when running unit tests

I'm running junit tests a lot from intellij , that's how i develop/debug my code. the starting of the unit tests takes much too long to execute even if there was no change in the code, just executing the test again with no changes. this is very annoying and consumes many minutes out of my working hours. of curse the run/debug configuration is configured to build before launch but if there was no change i expect it to be very fast, and even with changes its too long. it can take 30 to 60 seconds before the unit tests starts.

is there anyway to improve that?