Setup

In order to properly test your application, it is recommended to use TestFX alongside Mockito. For a full explanation of both libraries, checkout their official documentation, as the following documentation will only cover a small part of what the projects have to offer.

TestFX

TestFX can be used to test the frontend of your application by checking if certain requirements are met, for example view elements being visible or having a certain property.

Alongside TestFX, we also include Monocle which allows for headless testing without the app having to be open on your screen every time the tests run.

    testImplementation group: 'org.testfx', name: 'testfx-junit5', version: testFxVersion
    testImplementation group: 'org.testfx', name: 'openjfx-monocle', version: monocleVersion

To enable headless testing, the following lines can be added to your test gradle task:

test {
    // ...
    if (hasProperty('headless') || System.getenv('CI')) {
        systemProperties = [
                'java.awt.headless': 'true',
                'testfx.robot'     : 'glass',
                'testfx.headless'  : 'true',
                'glass.platform'   : 'Monocle',
                'monocle.platform' : 'Headless',
                'prism.order'      : 'sw',
                'prism.text'       : 't2k',
        ]
    }
}

Whenever the tests are ran with CI=true, headless mode will be enabled allowing for testing in CI environments like GitHub Actions. In order to fix some issues with tests running in headless mode, make sure to set the stage’s coordinates to a value like (0, 0) because otherwise some calculations can fail due to the position being NaN.

Mockito

Mockito is used to redefine certain methods in the code which currently aren’t being tested but could influence the test results, for example by accessing an external API.

testImplementation group: 'org.mockito', name: 'mockito-junit-jupiter', version: mockitoVersion

---

Overview

Testing Controllers ➡