Tests

Remarks#

Parameter	Context	Details
@BeforeClass	Static	Executed when the class is first created
@Before	Instance	Executed before each test in the class
@Test	Instance	Should be declared each method to test
@After	Instance	Executed after each test in the class
@AfterClass	Static	Executed before destruction of the class

Example Test Class Format

public class TestFeatureA {

    @BeforeClass
    public static void setupClass() {}
    
    @Before
    public void setupTest() {}
    
    @Test
    public void testA() {}
    
    @Test
    public void testB() {}
    
    @After
    public void tearDownTest() {}
    
    @AfterClass
    public static void tearDownClass() {}
    
    }
}

Unit testing using JUnit

Fixtures

Unit testing using Theories

Performance measurement

If you need to check if your testing method takes too long to execute, you can do that by mentioning your expected execution time using timeout property of @Test annotation. If the test execution takes longer than that number of milliseconds it causes a test method to fail.

public class StringConcatenationTest {

    private static final int TIMES = 10_000;
    
    // timeout in milliseconds
    @Test(timeout = 20)
    public void testString(){

        String res = "";

        for (int i = 0; i < TIMES; i++) {
            res += i;
        }

        System.out.println(res.length());
    }

    @Test(timeout = 20)
    public void testStringBuilder(){

        StringBuilder res = new StringBuilder();

        for (int i = 0; i < TIMES; i++) {
            res.append(i);
        }

        System.out.println(res.length());
    }

    @Test(timeout = 20)
    public void testStringBuffer(){

        StringBuffer res = new StringBufferr();

        for (int i = 0; i < TIMES; i++) {
            res.append(i);
        }

        System.out.println(res.length());
    }

}

In most cases without JVM warm-up testString will fail. But testStringBuffer and testStringBuilder should pass this test successfully.