Headless testing with JavaFx and TestFx

Question

I have a simple JavaFx application (Java 8) that has a unit test using TestFx. However, when the test is run, the application window starts up and the mouse is moved to do w

Answer 1

Update:

I found this blog post that provides the solution for me to this problem. As the author suggests, you need to add the following dependency to your build:

testRuntime 'org.testfx:openjfx-monocle:1.8.0_20'

Then you will need to include the following somewhere before you call registerPrimaryStage(), in my case in a method marked with @BeforeClass as I am using JUnit:

System.setProperty("testfx.robot", "glass");
System.setProperty("testfx.headless", "true");
System.setProperty("prism.order", "sw");
System.setProperty("prism.text", "t2k");

I would also add that its useful to include System.setProperty("java.awt.headless", "true") to ensure that you're not relying on anything from the AWT (in my case I had a call to get the size of the screen that was causing problems). I also followed the blog author's advice to add a switch to turn headless mode on and off. This gives the final method as follows:

@BeforeClass
public static void setupSpec() throws Exception {
    if (Boolean.getBoolean("headless")) {
        System.setProperty("testfx.robot", "glass");
        System.setProperty("testfx.headless", "true");
        System.setProperty("prism.order", "sw");
        System.setProperty("prism.text", "t2k");
        System.setProperty("java.awt.headless", "true");
    }
    registerPrimaryStage();
}

You can see the solution in context here

Original Answer:

If you're using Linux, you can use xvfb for this. On a Debian-based system you can install xvfb as follows:

$ sudo apt-get install xvfb

With xvfb installed, run the following before you run your tests:

$ Xvfb :99 &>/dev/null &
$ export DISPLAY=:99

If you launch your tests in the same console TestFX will use the frame buffer instead of your main display. Thus the tests will run but you won't be bothered with windows opening and the mouse pointer being moved around.