Running test in already compiled project takes ~3 seconds

Hello,

When I'm running unit test in already compiled project, it takes about 3 secods for IntelliJ to actually run the test. During this time it shows "Make" in progress bar.
I was wondering what could be the bottleneck.

(IntelliJ caches are on RAM disk. Incremental compilation is turned on. IJ 12.1.6, jdk 1.7, windows 7.)

Thank you