swing-test

swing-test is an idiomatic testing library for Java Swing components, developed in Kotlin

Test components with ease

Write simple assertions for Swing components, using the StringSpec style.

@Test
fun `Should enable Ok button once terms have been read`() {
    val form = MyForm()
    form.getChild<JButton>("Ok").shouldBeDisabled()
    form.clickChild<JCheckBox>("I have read the terms and conditions")
    form.getChild<JButton>("Ok").shouldBeEnabled()
}

Easily interact with whole layouts

Use in-built finders to interact with child components without having to expose them directly. Out-the-box support for narrowing by class, text and toolTipText, plus the ability to specify your own lambda for more complex cases:

val myContainer = MyContainer()
myContainer.findChild<JButton>(text = "Cancel").shouldBeNull()
myContainer.getChild<JLabel>(toolTipText = "Avatar").shouldBeVisible()

// Custom example
myContainer.clickChild<JRadioButton> { it.text.contains("foo") }

Simulate common interactions once you have a reference to the component you're after:

val label = myContainer.getChild<JLabel>()
label.doHover() //fires mouseEntered on listeners
label.doHoverAway() //fires mouseExited
label.doubleClick() //simulates mouseClicked/mouseReleased, with clickCount = 2

val table = myContainer.getChild<JTable>()
table.simulateKeyPress(KeyEvent.VK_ENTER) //Simulate the enter key being pressed

Snapshot Testing 📸

swing-test provides a simple one-line approach for verifying that components match a generated png snapshot file. This is particularly useful for testing components with custom painting logic, which can otherwise be hard to verify:

@Test
fun `Should match snapshot - locked`() {
    val achievement = AchievementMedal(AchievementStatus.LOCKED)
    achievement.shouldMatchImage("locked")
}

@Test
fun `Should match snapshot - red`() {
    val achievement = AchievementMedal(AchievementStatus.RED)
    medal.shouldMatchImage("red")
}

Snapshot images are automatically written to src/test/resources/__snapshots__/your/package/structure/test-class/imageName.png, for example:

• Running with the system property updateSnapshots=true allows the image files to be created for the first time, or updated locally in the event of a deliberate change.
• When a snapshot comparison fails, the failed image file is written out with the same name and a failed.png extension, to allow easy manual inspection.
• Due to pixel differences caused by running on different operating systems, you may optionally specify a screenshotOs system property, e.g. screenshotOs=linux. This will cause any screenshot tests to be skipped when run on a different operating system.

Fully interoperable with Java

Although swing-test is developed with Kotlin in mind, it fully supports raw Java projects too:

Component myComponent = new CustomComponent();
SwingSnapshotsKt.shouldMatchImage(myComponent,"Default");

List<JButton> buttons=ComponentFindersKt.findAll(myComponent,JButton.class);

ComponentInteractionsKt.doHover(myComponent);