[java] Setting up JUnit with IntelliJ IDEA

Familiar with Java but unfamiliar with IntelliJ, how does one "get started" with JUnit integration?

Inspired by Looking for a tutorial on using JUnit with Intellij IDEA 9.x which didn't answer my questions and was for an older version of IntelliJ.

I needed to enable the JUnit plugin, after I linked my project with the jar files.

To enable the JUnit plugin, go to File->Settings, type "JUnit" in the search bar, and under "Plugins," check "JUnit.

vikingsteve's advice above will probably get the libraries linked right. Otherwise, open File->Project Structure, go to Libraries, hit the plus, and then browse to

C:\Program Files (x86)\JetBrains\IntelliJ IDEA Community Edition 14.1.1\lib\

and add these jar files:

hamcrest-core-1.3.jar
junit-4.11.jar 
junit.jar 

1. Create and setup a "tests" folder
   • In the Project sidebar on the left, right-click your project and do New > Directory. Name it "test" or whatever you like.
   • Right-click the folder and choose "Mark Directory As > Test Source Root".
2. Adding JUnit library
   • Right-click your project and choose "Open Module Settings" or hit F4. (Alternatively, File > Project Structure, Ctrl-Alt-Shift-S is probably the "right" way to do this)
   • Go to the "Libraries" group, click the little green plus (look up), and choose "From Maven...".
   • Search for "junit" -- you're looking for something like "junit:junit:4.11".
   • Check whichever boxes you want (Sources, JavaDocs) then hit OK.
   • Keep hitting OK until you're back to the code.

3. Write your first unit test

   • Right-click on your test folder, "New > Java Class", call it whatever, e.g. MyFirstTest.

   • Write a JUnit test -- here's mine:

     import org.junit.Assert;
     import org.junit.Test;
     
     public class MyFirstTest {
         @Test
         public void firstTest() {
             Assert.assertTrue(true);
         }
     }
     

4. Run your tests
   • Right-click on your test folder and choose "Run 'All Tests'". Presto, testo.
   • To run again, you can either hit the green "Play"-style button that appeared in the new section that popped on the bottom of your window, or you can hit the green "Play"-style button in the top bar.