How do I write and run a simple test

How do I write and run a simple test?

1. Create a class:

   
   
   package junitfaq;
   
   import org.junit.*;
   import static org.junit.Assert.*;
   
   import java.util.*;
   
   public class SimpleTest {
   

2. Write a test method (annotated with @Test) that asserts expected results on the object under test:

   
   
   @Test
   public void testEmptyCollection() {
   Collection collection = new ArrayList();
   assertTrue(collection.isEmpty());
   }
   

3. If you are running your JUnit 4 tests with a JUnit 3.x runner, write a suite() method that uses the JUnit4TestAdapter class to create a suite containing all of your test methods:

   
   
   public static junit.framework.Test suite() {
   return new junit.framework.JUnit4TestAdapter(SimpleTest.class);
   }
   

4. Although writing a main() method to run the test is much less important with the advent of IDE runners, it's still possible:

   
   
   public static void main(String args[]) {
   org.junit.runner.JUnitCore.main("junitfaq.SimpleTest");
   }
   }
   

5. Run the test:

   • To run the test from the console, type:

     java org.junit.runner.JUnitCore junitfaq.SimpleTest

   • To run the test with the test runner used in main(), type:

     java junitfaq.SimpleTest

   The passing test results in the following textual output:

   
   .
   Time: 0
   
   OK (1 tests)