JUnit Rules

La anotación @Rule en JUnit permite marcar campos públicos de una clase de Test que sean de tipo MethodRule (o una implementación de este).

Permite ejecutar código antes, después o en lugar del método de test, como:

Si creo una implementación de MethodRule implementaré el método public Statement apply(final Statement base, final FrameworkMethod method, final Object target) que me permite decidir que métodos interceptar, por ejemplo:

Para mi clase DummyTest:

public class DummyTest {

@Rule

public IgnoreLeadingFailure ilf = new IgnoreLeadingFailure();

@Test

public void testTest() {

assertTrue(false);

}

}
public class IgnoreLeadingFailure implements MethodRule {

private final static String PROPERTY_FILE_NAME = "activatedTests.properties";

private final static Properties activatedTests = new Properties();

static {

try {

activatedTests.load(new FileInputStream(PROPERTY_FILE_NAME));

} catch (IOException e) {

// actually this is to be expected on the first run

System.out.println("Couldn’t load Properties from file" + e);

}

}

public Statement apply(final Statement base, final FrameworkMethod method,

final Object target) {

if (activatedTests.containsKey(getFullTestMethodName(method, target))) {

return base;

} else {

return new Statement() {

@Override

public void evaluate() throws Throwable {

try {

base.evaluate();

activateTest(getFullTestMethodName(method, target));

} catch (Throwable t) {

throw new AssumptionViolatedException(

"This test never succeeded before, and failed again with: "

+ t.toString());

}

}

private void activateTest(String fullTestMethodName) {

activatedTests.put(fullTestMethodName,

new SimpleDateFormat().format(new Date()));

try {

activatedTests.store(new FileOutputStream(

PROPERTY_FILE_NAME),

"tests that ran successfully at least once");

} catch (IOException io) {

System.out.println("failed to store properties" + io);

}

}

};

}

}

private String getFullTestMethodName(final FrameworkMethod method,

Object target) {

return target.getClass().getName() + " " + method.getName();

}

}

Podéis leer más aquí:

http://blog.schauderhaft.de/2009/10/04/junit-rules/

http://blog.mycila.com/2009/11/writing-your-own-junit-extensions-using.html

http://cwd.dhemery.com/2011/01/what-junit-rules-are-good-for/

Deja un comentario