Vaadin Testbench - Known Issues
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Known Issues

This section provides information and instructions on a few features that are known to be difficult to use or need modification to work.

Latest Firefox Compatibility

Mozilla Firefox changed important APIs in version 48 that affected their compatibility with WebDriver which directly affects TestBench. Geckodriver used for the latest Firefox versions (48 and newer) does not support actions API. In practice, meaning that you can not simulate context click and double click in tests. It also means that some parts of the Element API just will not work. It is recommended to use either Firefox 45 ESR or Firefox 47 with GeckoDriver. You should use GeckoDriver in legacy mode with Firefox 45 ESR and Firefox 47, by setting FirefoxDriver.MARIONETTE to false:

@Before
public void setup() {
    FirefoxBinary binary = new FirefoxBinary(new File(pathToFirefox));
    FirefoxProfile firefoxProfile = new FirefoxProfile();
    DesiredCapabilities capabilities = DesiredCapabilities.firefox();
    // Enable legacy mode
    capabilities.setCapability(FirefoxDriver.MARIONETTE, false);

    WebDriver driver = new FirefoxDriver(binary,firefoxProfile,capabilities);
    setDriver(driver);
}

Running Firefox Tests on Mac OS X

Firefox needs to have focus in the main window for any focus events to be triggered. This sometimes causes problems if something interferes with the focus. For example, a TextField that has an input prompt relies on the JavaScript onFocus() event to clear the prompt when the field is focused.

The problem occurs when OS X considers the Java process of an application using TestBench (or the node service) to have a native user interface capability, as with AWT or Swing, even when they are not used. This causes the focus to switch from Firefox to the process using TestBench, causing tests requiring focus to fail. To remedy this problem, you need to start the JVM in which the tests are running with the -Djava.awt.headless=true parameter to disable the user interface capability of the Java process.

Note that the same problem is present also when debugging tests with Firefox. We therefore recommend using Chrome for debugging tests, unless Firefox is necessary.

Random Failures with Internet Explorer Driver

Unfortunately, a TestBench test may sometimes behave unexpectedly, causing random failures. One of the reasons for these random failures is problems with the Internet Explorer Driver. Internet Explorer specification requires browser window to be focused to receive user events, while Selenium Web Driver specification points out that Web Driver should work without window focus. You can get more information about it from Internet Explorer Driver documentation.

TestBench provides a workaround to this problem. Use RetryRule(int maxAttempts) rule to re-run a test several times in case of a random failure. Use maxAttempts to specify the maximum number of attempts for running tests. The test passes as soon as one attempt is executed without any errors, i.e. it is only run as many times as needed.

public class RandomFailureTest extends TestBenchTestCase {
    // Run the test two times
    @Rule
    public RetryRule rule = new RetryRule(2);

    @Test
    public void emptyTest() {
    }

}
RetryRule affects all the test methods in the class and also child classes.
The default value of maxAttempts is 1, meaning that tests run only once. You can change the value of maxAttempts using the Java system property: -Dcom.vaadin.testbench.Parameters.maxAttempts=2. This will affect all the TestBench tests.
Use RetryRule when you are sure that the test fails because of the problems with the Web Driver, but not your application. Using RetryRule without cautions may hide random problems happening in your application.