Writing White Box Test Cases

For white box test cases, we can automate our test cases by creating a test class. By convention, JUnit test classes should be named <nameOfSourceClass>Test.java. Therefore, the test class for a program called Paycheck would be PaycheckTest. All test classes will go in the test directory.

If our program under test contains methods, we can call methods in the program under test similarly to how we call methods of the Math class:

<ProgramUnderTest>.<methodName>(<parameters>);

When creating a test program, the test cases can be broken out into methods. You can have one or more test method for each method under test. A good naming convention is to call your test method test<MethodName><DescriptionOfTest>.

Inside of each test method, we need to use one or more JUnit assert statements.

JUnit Annotations

The test class includes different types of methods that have the following annotations:

@Before is used to identify a method that executes before each of your individual test methods. This is useful for constructing new objects and ensures that each test executes with the same initial starting conditions.
@Test is used to identify each test method in your test class.

PaycheckTest Example

import org.junit.*;
import junit.framework.TestCase;

/**
 * Test class for the Paycheck program.
 * 
 * @author Sarah Heckman
 * @author Jessica Young Schmidt
 */
public class PaycheckTest extends TestCase {

    /**
     * Test the Paycheck.getPayRate() method.
     */
    @Test
    public void testGetPayRate() {

    }

    /**
     * Test the Paycheck.calculateRegularPay() method.
     */
    @Test
    public void testCalculateRegularPay() {

    }

    /**
     * Test the Paycheck.calculateOvertimePay() method.
     */
    @Test
    public void testCalculateOvertimePay() {

    }

    /**
     * Test the Paycheck.calculateGrossPay() method.
     */
    @Test
    public void testCalculateGrossPay() {

    }

    /**
     * Test the Paycheck.calculateTotalDeductions() method.
     */
    @Test
    public void testCalculateRetirement() {

    }

    /**
     * Test the Paycheck.calculateNetPay() method.
     */
    @Test
    public void testCalculateNetPay() {

    }

}

Figure 4: Skeleton of the Paycheck program.

The extends keyword suggests an ‘is-a’ relationship. For example, PaycheckTest is-a TestCase. You will learn more about extends and the ‘is-a’ relationship in CSC216.

The directory structure should now be:

Paycheck
    -> src 
        -> Paycheck.java
    -> test
        -> PaycheckTest.java
    -> lib 
        -> junit-4.12.jar
        -> hamcrest-core-1.3.jar
    -> bin
        -> Paycheck.class
    -> doc
    -> project_docs
        -> Black Box Test Plan

Assert Statements

The JUnit library includes many different types of assert statements. The common ones you may use are outlined in the table below.¹

Statement	Description
`assertTrue(value)`	asserts that the `value` passed as a parameter is `boolean true`. If it is not `true`, the test case will fail.
`assertTrue(message, value)`	asserts that the `value` passed as a parameter is `boolean true`. If it is not `true`, the test case will fail with the given message.
`assertFalse(value)`	asserts that the `value` passed as a parameter is `boolean false`. If it is not `false`, the test case will fail.
`assertFalse(message, value)`	asserts that the `value` passed as a parameter is `boolean false`. If it is not `false`, the test case will fail with the given message.
`assertEquals(expectedValue, actualValue)`	asserts that `expectedValue` equals the `actualValue`. If the two values are not equal, the test case will fail.
`assertEquals(message, expectedValue, actualValue)`	asserts that `expectedValue` equals the `actualValue`. If the two values are not equal, the test case will fail with the given.
`assertEquals(expectedValue, actualValue, delta)`	asserts that `expectedValue` and `actualValue` are equal to within a positive `delta`. Otherwise, the test case will fail.
`assertEquals(message, expectedValue, actualValue, delta)`	asserts that `expectedValue` and `actualValue` are equal to within a positive `delta`. Otherwise, the test case will fail.

Footnotes

For this course, you are expected to use the assert methods that include message. Your message will include your test description. ↩

White Box Testing: Download JUnit Libraries

White Box Testing: Compile and Execute the Test Cases

Software Testing

White Box Testing: Write Test Cases

Writing White Box Test Cases

JUnit Annotations

PaycheckTest Example

Assert Statements

Footnotes