How to create a test directory in Intellij 13?
You should have structure like this one:
[] .idea
[] src
[] main
[] java
com.simpleproject
SimpleClass.java
[] resources
[] test
[] java
com.simpleproject
SimpleClassTest.java
[] resources
After that go to: File->Project Structure->Modules and in "Sources" tab you can choose which folder is "test folder" (usually java in test), which "sources" (usually java in main) etc by clicking "Mark as" options.