In JUnit 3, in order to create test cases, we need to extend the class junit.framework.TestCase. This base class includes the framework code that JUnit needs to automatically run the tests. Then, we simply make sure that the method name follows the testXXX() pattern. This naming convention makes it clear to the framework that the method is a unit test and that it can be run automatically.
The test life cycle is controlled in the setup() and tearDown()methods. The TestCase calls setup() before running each of its tests and then calls teardown() when each test is complete. One reason to put more than one test method into the same test case is to share the same test fixture.
Finally, in order to implement the verification stage in the test case, JUnit 3 defines several assert methods in a utility class named junit.framework.Assert. The following table summarizes the main assertions provided by this class:
| Method | Description |
| assertTrue | Asserts that a condition is true. If it isn’t, the method throws an AssertionFailedError with the given message (if any). |
| assertFalse | Asserts that a condition is false. If it isn’t, the method throws an AssertionFailedError with the given message (if any). |
| assertEquals | Asserts that two objects are equal. If they are not, the method throws an AssertionFailedError with the given message (if any). |
| assertNotNull | Asserts that an object is not null. If it is, the method throws an AssertionFailedError with the message (if any). |
| assertNull | Asserts that an object is null. If it isn’t, the method throws an AssertionFailedError with the given message (if any). |
| assertSame | Asserts that two objects refer to the same object. If they do not, the method throws an AssertionFailedError with the given message (if any). |
| assertNotSame | Asserts that two objects do not refer to the same object. If they do, the method throws an AssertionFailedError with the given message (if any). |
| fail | Fails a test (throwing AssertionFailedError) with the given message (if any). |
The following class shows a simple test implemented with JUnit 3.8.2. As we can see, this test case contains two tests. Before each test, the method setUp() will be invoked by the framework, and after the execution of each test, the method tearDown() will be also invoked. This example has been coded so that the first test, named testSuccess() finishes correctly, and the second test named testFailure() ends with an error (the assertion throws an exception):
package io.github.bonigarcia;
import junit.framework.TestCase;
public class TestSimple extends TestCase {
// Phase 1: Setup (for each test)
protected void setUp() throws Exception {
System.out.println("<Setup>");
}
// Test 1: This test is going to succeed
public void testSuccess() {
// Phase 2: Simulation of exercise
int expected = 60;
int real = 60;
System.out.println("** Test 1 **");
// Phase 3: Verify
assertEquals(expected + " should be equals to "
+ real, expected, real);
}
// Test 2: This test is going to fail
public void testFailure() {
// Phase 2: Simulation of exercise
int expected = 60;
int real = 20;
System.out.println("** Test 2 **");
// Phase 3: Verify
assertEquals(expected + " should be equals to "
+ real, expected, real);
}
// Phase 4: Teardown (for each test)
protected void tearDown() throws Exception {
System.out.println("</Ending>");
}
}