Test Cases Made Easy with JUnit 4.5

Writing a Test Case

Listing 2 shows a set of JUnit 4.5 test cases for NumberCruncher.java. Listing 2.1 shows some of the equivalent test cases using JUnit 3.8.

Listing 2: NumberCruncherTestCase45.java

package com.dlt.developer.junit;

import com.dlt.developer.numbers.NumberCruncher;

import org.junit.*;

import static org.junit.Assert.*;

public class NumberCruncherTestCase45 {

   @BeforeClass
   public static void init() {
        // Do one-time setup for all test cases
   }    // init()

   @Before
   public void doSetup() {
        // Do setup before each test case
   }    // setUp()

   @After
   public void doTearDown() {
        // Do tear down after each test case
   }    // tearDown()

   @AfterClass
   public static void destroy() {
        // Do tear-down after all test cases are finished
   }    // destroy()

   @Test
   public void testIsPrime() {
      NumberCruncher nc = new NumberCruncher();
      assertTrue("17 is a prime number",
                 nc.isPrime(new Integer(17)));
      assertFalse("16 is not a prime number",
                  nc.isPrime(new Integer(16)));
   }    // testIsPrime()

   @Test
   public void testFactorial() {
      NumberCruncher nc = new NumberCruncher();
      assertEquals(new Integer(120), nc.factorial(new Integer(5)));
   }    // testFactorial()

   @Test (expected = IllegalArgumentException.class)
   public void testFactorialInvalid() {
      NumberCruncher nc = new NumberCruncher();
      nc.factorial(new Integer(-4));
   }    // testFactorialInvalid()

   @Test (timeout = 5000)
   public void testDoForever() {
      NumberCruncher nc = new NumberCruncher();
      assertEquals(new Integer(0), nc.doForever());
   }    // testDoForever()

   @Test
   public void testGetFactors() {
      NumberCruncher nc = new NumberCruncher();
      Object[] f1 = nc.getFactors(new Integer(32));
      Object[] f2 = nc.getFactors(new Integer(32));
      assertEquals("Factors are equal", f1, f2);
   }    // testGetFactors()

   @Ignore ("Not ready yet")
   public void testSomethingElse() {
      NumberCruncher nc = new NumberCruncher();
   }    // testSomethingElse()

} // NumberCruncherTestCase45

Listing 2.1: NumberCruncherTestCase38.java

package com.dlt.developer.junit;

import com.dlt.developer.numbers.NumberCruncher;
   import junit.framework.TestCase;

public class NumberCruncherTestCase38 extends TestCase {


   public void setup() {
        // Do setup before each test case
   }    // setUp()

   public void tearDown() {
        // Do tear down after each test case
   }    // tearDown()


   public void testIsPrime() {
      NumberCruncher nc = new NumberCruncher();
      assertTrue("17 is a prime number",
                  nc.isPrime(new Integer(17)));
         assertFalse("16 is not a prime number",
                     nc.isPrime(new Integer(16)));
   }    // testIsPrime()

   public void testFactorial() {
      NumberCruncher nc = new NumberCruncher();
      assertEquals(new Integer(120), nc.factorial(new Integer(5)));
   }    // testFactorial()

   public void testFactorialInvalid() {
      NumberCruncher nc = new NumberCruncher();
      boolean gotException = false;
      try {
         nc.factorial(new Integer(-4));
      } catch (IllegalArgumentException ex) {
         gotException = true;
      }    // catch
      assertTrue("Factorial Validation", gotException);
   }    // testFactorialInvalid()

   public void testGetFactors() {
      NumberCruncher nc = new NumberCruncher();
      Object[] f1 = nc.getFactors(new Integer(32));
      Object[] f2 = nc.getFactors(new Integer(32));
      assertTrue("Factor Arrays Equal Length",
                 f1.length == f2.length);
      for (int i = 0; i < f1.length; i++) {
         assertTrue("Array Element " + i + " Is Equal",
                    f1[i].equals(f2[i]));
      }    // for i
   }    // testGetFactors()

}    // NumberCruncherTestCase38

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This article was originally published on November 12, 2008