JUnit4 in 60 Seconds

copy from http://www.cavdar.net/2008/07/21/junit-4-in-60-seconds/

 

played with JUnit 4 library this weekend and here is the short introduction to it:

1. @Test
   Mark your test cases with @Test annotations. You don’t need to prefix your test cases with “test”.  In addition, your class does not need to extend from “TestCase” class. (My note: 如果你的class不幸继承了TestCase的话，那么还将沿用Junit3的那一套寻找测试函数的模式(即函数名test***)@Test 这个annotattion将无效。
   

 

    @Test  
    public void addition() {  
        assertEquals(12, simpleMath.add(7, 5));  
    }  
      
    @Test  
    public void subtraction() {  
       assertEquals(9, simpleMath.substract(12, 3));  
    }  

 2. @Before and @After

1. Use @Before and @After annotations for “setup” and “tearDown” methods respectively. They run before and after every test case.
   @Before
   public void runBeforeEveryTest() {
   simpleMath = new SimpleMath();
   }
   
   @After
   public void runAfterEveryTest() {
   simpleMath = null;
   }

    

   	@Before
   	public void runBeforeEveryTest() {
   		simpleMath = new SimpleMath();
   	}
   	@After
   	public void runAfterEveryTest() {
   		simpleMath = null;
   	}
   

2. @BeforeClass and @AfterClass
   Use @BeforeClass and @AfterClass annotations for class wide “setup” and “tearDown” respectively. Think them as one time setup and tearDown. They run for one time before and after all test cases.

       @BeforeClass  
       public static void runBeforeClass() {  
           // run for one time before all test cases  
       }  
         
       @AfterClass  
       public static void runAfterClass() {  
           // run for one time after all test cases  
       }  

    

   	@BeforeClass
   	public static void runBeforeClass() {
   		// run for one time before all test cases
   	}
   	@AfterClass
   	public static void runAfterClass() {
   		// run for one time after all test cases
   	}
   

3. Exception Handling
   Use “expected” paramater with @Test annotation for test cases that expect exception. Write the class name of the exception that will be thrown.

       @Test(expected = ArithmeticException.class)  
       public void divisionWithException() {  
           // divide by zero  
           simpleMath.divide(1, 0);  
      }  

    

   	@Test(expected = ArithmeticException.class)
   	public void divisionWithException() {
   		// divide by zero
   		simpleMath.divide(1, 0);
   	}
   

4. @Ignore
   Put @Ignore annotation for test cases you want to ignore. You can add a string parameter that defines the reason of ignorance if you want.
   

       @Ignore("Not Ready to Run")  
       @Test  
       public void multiplication() {  
           assertEquals(15, simpleMath.multiply(3, 5));  
       }  

    

   	@Ignore("Not Ready to Run")
   	@Test
   	public void multiplication() {
   		assertEquals(15, simpleMath.multiply(3, 5));
   	}
   

5. Timeout
   Define a timeout period in miliseconds with “timeout” parameter. The test fails when the timeout period exceeds.

       @Test(timeout = 1000)  
       public void infinity() {  
           while (true)  
               ;  
       }  

    

   	@Test(timeout = 1000)
   	public void infinity() {
   		while (true)
   			;
   	}
   

6. New Assertions
   Compare arrays with new assertion methods. Two arrays are equal if they have the same length and each element is equal to the corresponding element in the other array; otherwise, they’re not.

   public static void assertEquals(Object[] expected, Object[] actual);
public static void assertEquals(String message, Object[] expected, Object[] actual);

    @Test  
    public void listEquality() {  
        List<Integer> expected = new ArrayList<Integer>();  
        expected.add(5);  
      
        List<Integer> actual = new ArrayList<Integer>();  
        actual.add(5);  
      
        assertEquals(expected, actual);  
    } 

    

   	@Test
   	public void listEquality() {
   		List<Integer> expected = new ArrayList<Integer>();
   		expected.add(5);
   		List<Integer> actual = new ArrayList<Integer>();
   		actual.add(5);
   		assertEquals(expected, actual);
   	}
   

7. JUnit4Adapter
   Run your Junit 4 tests in Junit 3 test runners with Junit4Adapter.

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

    

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

Happy coding.

 

 

My Note goes here:

文中没有提到JUnit4中TestSuite的用法，新的用法TestSuite.addTest(..)已经不再适用，因为新的testclass都没有extends TestCase.取而代之的用法如下:

import junit.framework.Test;
import junit.framework.TestSuite;

import org.junit.runner.RunWith;
import org.junit.runners.Suite;
import org.junit.runners.Suite.SuiteClasses;

@RunWith(Suite.class)
@SuiteClasses({YouTestCaseOne.class,YourTestCase2.class})
public class AllTests {

}