Combine more than 2 projects and run using gradle clean test

I have downloaded 2 test cases from testproject. These are 2 different java+gradle projects. Now i want to run them as single project by adding these two as subprojects to a root project. When i am running it using build.gradle, its picking only the first one. Any idea what changes i need to do with build.gradle of the root and subprojects? Thanks in advance