JUnit expected exception test

Expected exception test is used for the methods which can throw an exception. We have to specify expected exception in @Test(expected = expectedException.class) action. If expected exception or any of its subclass exception is thrown by the method then JUnit will pass this unit test.

Example:

DivisionTestCase.java

import com.w3spoint.business.*;
import static org.junit.Assert.*;
import org.junit.Test;
 
/**
 * This is test case class for division method.
 * @author w3spoint
 */
public class DivisionTestCase {
	//DivisionTest class objects
	DivisionTest divisionTest1 = new DivisionTest(10, 2); 
	DivisionTest divisionTest2 = new DivisionTest(10, 0); 
 
	//Test case for division
	@Test
	public void test() {
		assertEquals(5, divisionTest1.division());
	}
 
	//Test case for expected ArithmeticException, 
	//As in this case ArithmeticException
	// is the expected exception so JUnit 
	//will pass this unit test. 
	@Test(expected = ArithmeticException.class)  
	public void testException() {
		assertEquals(5, divisionTest2.division());
	}
}

DivisionTest.java

/**
 * This is simple java class containing division method.
 * @author w3spoint
 */
public class DivisionTest {
	//data members
	int num1, num2;
 
	//parameterised constructor
	public DivisionTest(int num1, int num2){
		this.num1 = num1;
		this.num2 = num2;
	}
 
	//division method
	public int division() throws ArithmeticException{
		return num1/num2;
	}
}

Output:

junit2

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