Hadoop's test suite takes a long time to run. Steve Loughran and Doug Cutting have done some work to speeding them up: see HADOOP-3694. In the meantime if you want to focus on a particular test, follow Steve's HadoopUnderIDEA instructions on the wiki, and add a "test.include" property to build.properties. For example to focus on just TestCLI.java, add the property "test.include=TestCLI*". The ideal thing would be to have IDEA pick up a global test config, but I haven't figured out how to do that yet.