Test pages and components

You need this when you want to check, without a browser or a server, that a page renders and reacts to the user as intended. WicketTester runs your application in memory: it renders pages, clicks links, submits forms and fires Ajax events, and remembers the last rendered page and response so you can check them. Test a page with WicketTester is a step-by-step introduction; WicketTester lists every method.

Add the dependencies

pom.xml

<dependency>
    <groupId>org.apache.wicket</groupId>
    <artifactId>wicket-tester</artifactId>
    <version>${wicket.version}</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.junit.jupiter</groupId>
    <artifactId>junit-jupiter</artifactId>
    <scope>test</scope>
</dependency>

The quickstart project already has both.

Render a page

Create a tester with your application, start a page and check that it rendered. Create a new tester for every test and destroy it afterwards, so tests do not share an application or a session.

HomePageTest.java

class HomePageTest {
    private WicketTester tester;

    @BeforeEach
    void setUp() {
        tester = new WicketTester(new WicketApplication());
    }

    @AfterEach
    void tearDown() {
        tester.destroy();
    }

    @Test
    void rendersSuccessfully() {
        tester.startPage(HomePage.class);
        tester.assertRenderedPage(HomePage.class);
    }
}

startPage also takes PageParameters or a page instance. new WicketTester() without arguments uses a MockApplication, which is enough for components that do not depend on your application class.

Check what a component shows

Components are addressed by their path from the page: the ids of the containers, separated by colons.

tester.assertLabel("greeting", "Hello, Ada");
tester.assertComponent("form:name", TextField.class);
tester.assertVisible("form:save");
tester.assertInvisible("adminPanel");
tester.assertDisabled("form:delete");
tester.assertModelValue("form:name", "Ada");
tester.assertContains("<h1>Orders</h1>");

assertContains matches a regular expression against the whole response. getComponentFromLastRenderedPage(path) gives you the component itself for anything the assert methods do not cover.

Click a link

tester.startPage(CounterPage.class);
tester.assertLabel("count", "0");

tester.clickLink("increment");
tester.assertLabel("count", "1");

clickLink simulates a browser with JavaScript. For an AjaxLink it fires the Ajax event; for an AjaxFallbackLink too. clickLink(path, false) simulates a browser without JavaScript: an AjaxFallbackLink then does a normal request, and an AjaxLink fails the test.

Test Ajax

Fire an event on a component that has an AjaxEventBehavior, then check that the right components were added to the Ajax response:

tester.startPage(CounterPage.class);
tester.executeAjaxEvent("ajaxIncrement", "click");

tester.assertComponentOnAjaxResponse("count");
tester.assertLabel("count", "1");

executeBehavior(behavior) calls any AbstractAjaxBehavior directly, and executeAllTimerBehaviors(page) fires the timers on a page once.

Test a component on its own

startComponentInPage renders a component in a generated page, attached to a <span> tag. That suits panels and labels:

tester.startComponentInPage(new AddressPanel("address", Model.of(address)));
tester.assertLabel("address:city", "Amsterdam");

Paths may start with the id of the component you passed; the tester adds it when you leave it out. A component that needs a specific tag, such as a TextField or a Link, needs page markup of its own: pass it with startComponentInPage(component, markup) as an IMarkupFragment.

Check the response itself

getLastResponse() returns the MockHttpServletResponse of the last request, with its status, headers and content:

tester.startResource(new ReportResource());
MockHttpServletResponse response = tester.getLastResponse();
assertEquals(200, response.getStatus());
assertTrue(response.getDocument().startsWith("id,name"));

startResource and startResourceReference request a resource. executeUrl("./orders/42") requests any URL, which is how you test mounted pages and request mappers.

Set request headers

addRequestHeader sets a header on the next request only:

tester.addRequestHeader("Accept-Language", "nl-NL");
tester.startPage(HomePage.class);

An application with ResourceIsolationRequestCycleListener refuses listener requests that carry no Sec-Fetch-Site header. Add it before each click or submit:

tester.addRequestHeader(FetchMetadataResourceIsolationPolicy.SEC_FETCH_SITE_HEADER,
    FetchMetadataResourceIsolationPolicy.SAME_ORIGIN);
tester.clickLink("delete");

Use files from the web application folder

When your application loads markup or resources from src/main/webapp, tell the tester where that folder is. There is no servlet container to ask:

tester = new WicketTester(new WicketApplication(),
    new File("src/main/webapp").getAbsolutePath());

Forms have their own helper, FormTester; see Test forms. Markup details are easier to check with TagTester, described in Test markup.