The current version of documentation recommends to set the jvmArgs as the jvmArgs

tasks {
    test {
        jvmArgs("-javaagent:${mockitoAgent.asPath}")
     }
}

This is working when only Mockito agent is in use. As soon as another agent is expected (example for code coverage), this will fail as this overrides any previously registered agent. It will also remove all previously set jvmArgs.

To reproduce:
Both from IntelliJ

• Run tests requiring Mockito agent coinfigured as documented, it will succeed
• Re-run the same test with coverage, test will fail

Fix
The fix is trivial, instead of setting the jvmArgs, we need to add the entry instead.

tasks {
    test {
        jvmArgs.add("-javaagent:${mockitoAgent.asPath}")
     }
}

Tested with Grade 8.12 and Mockito 5.15.2

See