In Apache Wicket we can happily use
Or we could go for a Test-Driven Development approach. Let's make the application fail quickly in development if the message key is missing. No more forgetting.
First, we can create a jUnit test here
/src/test/java/[package]/MissingResourcesTestPageTestCase.javaWe could have changed the test to expect a WicketRuntimeException, but these can occur for many different reasons, such as the markup not existing at all. We want the test to fail if the resource could not be found.
import java.util.MissingResourceException;
import org.apache.wicket.PageParameters;
import org.apache.wicket.WicketRuntimeException;
import org.apache.wicket.util.tester.WicketTester;
import org.junit.Before;
import org.junit.Test;
public class MissingResourcesTestPageTestCase {
private WicketTester tester;
@Before
public void setup() {
tester = new WicketTester(new WicketApplication());
}
@Test(expected = MissingResourceException.class)
public void testMissingResourcePage() throws Throwable {
try {
tester.startPage(MissingResourcesTestPage.class, new PageParameters());
}
catch (final WicketRuntimeException wre) {
throw wre.getCause();
}
}
}
Sometimes I prefer creating the basic page first. Just the constructor so we can reference it from the unit test. The MoreUnit plugin for Eclipse can even create the jUnit test from the page with a keyboard shortcut. We can write this test first then use our IDE to create the
/src/test/java/[package]/MissingResourcesTestPage.java fileRunning the test now will fail because the markup does not exist. You can create an empty file called
import org.apache.wicket.markup.html.WebPage;
public class MissingResourcesTestPage extends WebPage {
public MissingResourcesTestPage() {
//do nothing to test markup rendering
}
}
/src/test/java/[package]/MissingResourcesTestPage.html and re-run the tests and it should still fail.Finally, add the markup
and run the test again. red. Wicket is working correctly and displaying the default text. So let's change it to start throwing exceptions.
<html>
<body>
<wicket:message key="this.resource.key.is.missing">this message resource is missing for testing purposes</wicket:message>
</body>
</html>
Alter your
/src/main/java/[package]/WicketApplication.java to override the init() method as follows:
public class WicketApplication extends WebApplication {
@Override
protected void init() {
super.init();
getResourceSettings().setUseDefaultOnMissingResource(false);
getResourceSettings().setThrowExceptionOnMissingResource(true);
}
}
setUseDefaultOnMissingResource(false) will mean Wicket won't try to use the default text inside the wicket:message tag when it can't find the resource key. Now it will just display nothing, which won't help our future tests. To cause an exception to be thrown you need to call setThrowExceptionOnMissingResource(true).
Run the test. Yay, green bar!
Done, done, done!
Anytime in the future that one of our developers creates a page and makes a typo, forgets to add the resource key, deletes a key, renames the resource file etc they will get a nice failed message when they run the tests. As long as they create tests to render the page. All developers do that, don't they?
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