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User:Michael.norman.oracle.com/Info on JUnit4
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Revision as of 20:13, 10 March 2014 by Unnamed Poltroon (Talk) (Jesse.Weinstein.clinicomp.com moved page /User:Michael.norman.oracle.com/Info on JUnit4 to User:Michael.norman.oracle.com/Info on JUnit4)
Contents
Introduction to JUnit4
- successor to most widely used unit-testing framework for Java, JUnit3
- under active development (last JUnit3 release 3.8.2 2006-03-03)
- JUnit 4 released 2006-02-16
- 4.1 2006-04-27
- 4.2 2006-11-16
- 4.3 2006-11-16
- 4.3.1 2007-03-28
- 4.4 (current as of 071204) 2007-07-18
- JUnit 4 released 2006-02-16
based on Java 5 features
- no longer need to extend class TestCase
- test-method names do not have to start with the prefix test
- mark your test method with a @Test annotation
- use static import's to get assert methods (instead of via inheritance)
importjunit.framework.TestCase; import org.junit.Test; import static org.junit.Assert.*; public class CalculatorTestextendsTestCase { @Test public voidtestadd() { .... assertEquals(4, calculator.add( 1, 3 )); } }
improved test lifecycle management
- setUp() and tearDown() replaced with @Before and @After annotations (allows for multiple @Before/@After methods)
public class CalculatorTest { @Before public void prepareTestData() { ... } @Before public void setupMocks() { ... } @After public void cleanupTestData() { ... } }
improved fixture management
JUnit3:
import junit.framework.*; import junit.extensions.TestSetup; public class AllTestsOneTimeSetup { public static Connection conn; // database connection public static Test suite() { TestSuite suite = new TestSuite(); TestSetup wrapper = new TestSetup(suite) { protected void setUp() { setUpDatabaseConnection(); } protected void tearDown() { tearDownDatabaseConnection(); } }; return wrapper; } public static void setUpDatabaseConnection() { // one-time initialization code conn = ...; } public static void tearDownDatabaseConnection() { // one-time initialization code conn.close() ...; } }
JUnit4: multiple @BeforeClass/@AfterClass annotations
import org.junit.AfterClass; import org.junit.BeforeClass; public class TestWithDatabaseConnection { public static Connection conn; // database connection fixture public static Object foo; // another fixture @BeforeClass public static void setUpDatabaseConnection() { conn = ...; } @BeforeClass public static void setUpFoo() { foo = ...; } @AfterClass public static void tearDownDatabaseConnection() { conn.close() ...; } }
Test Management
- handle expected exceptions more easily
- timeouts
- omit tests
JUnit3 style:
public void testDivideByZero() { boolean worked = false; try { new Calculator().divide( 4, 0 ); } catch (ArithmeticException e) { worked = true; } assertTrue("did not catch expected exception ", worked); }
JUnit4 style:
@Test(expected=ArithmeticException.class,timeout=5000) // set timeout so that we don't wait too long public void divideByZero() { new Calculator().divide( 4, 0 ); } @Ignore public void notQuiteReady() { ... }
Multiple Tests
- suite() method:
public class AllTests extends TestCase { public static Test suite() { TestSuite suite = new TestSuite(); suite.addTestSuite(CalculatorTest.class); suite.addTestSuite(AnotherTest.class); return suite; }
- vs. @SuiteClasses:
@RunWith(value=Suite.class) @SuiteClasses(value={CalculatorTest.class, AnotherTest.class}) public class AllTests { ... }
Custom Runners
In the previous section, we saw that the suite() was replaced with the @Suite annotation. This is an example of how JUnit4 has been designed to allow for extension and customization. The @RunWith annotation allows for custom behaviour to be implemented before, during or after each test and/or suite is run.
Weaknesses
- Tools integration
- JUnit3 has been integrated into alot of tools (Ant, Eclipse IDE, IDEA, etc). JUnit4 is at a disadvantage because it is new. I have written a special JUnit4 runner for Ant (works in 1.6.5 and 1.7.0) but it is not standard.
- Reporting
- The Ant JUnit3 runner has custom behaviour that allowed the run-output to be customized, generating aesthetically pleasing HTML pages. JUnit4 does not yet have this
- JDK 5 only