javajunit

Why is my exception not caught by Junit's assertThrows()

I have tried using a JavaFX ChangeListener to throw an exception when a JavaFX Property is set to an invalid value through a binding. This may not be the right way to go about reaching my purpose but now I am curious: I have not been able to test this behaviour with Junit5. Below are the files for a minimal working example of my attempt. I run this as a Gradle 8.12 Test task (.\gradlew.bat --configure-on-demand --rerun-tasks -x check test) in Netbeans 23 using Java 17.0.13 with Open JDK 64-bit for Windows.

To be clear: this question is not about how to prevent an invalid value to be set. What I'd like to know is why the test fails even though the expected exception is actually raised.

settings.gradle

rootProject.name = 'PropertyLimiterQuestion2'

build.gradle

plugins {
    id 'org.openjfx.javafxplugin' version '0.1.0'
}
apply plugin: 'application'

repositories {
    mavenCentral()
}

test {
    useJUnitPlatform()
}

javafx {
    version = '21.0.4'
    modules = [ 'javafx.controls', 'javafx.fxml' ]
}
dependencies {
    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.11.2'
    testImplementation 'org.junit.jupiter:junit-jupiter-params:5.11.2'
    testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.11.2'
}

src/test/java/PropertyLimiterQuestion2/PropertyValueLimiterTest.java

class PropertyValueLimiterTest {
    
    @Test
    void bind_invalidValue_MWE(){
        Set<String> allowedValues = Set.of("foo", "bar");
        Property<String> property = new SimpleObjectProperty<>("foo");
        ChangeListener<String> listener = (observable, oldValue, newValue) -> {
            if(! allowedValues.contains(newValue)){
                throw new IllegalArgumentException();
            }
        };
        property.addListener(listener);
        Assertions.assertThrows(IllegalArgumentException.class,
                () -> property.setValue("invalid"));
    }
}

When I run this task, two things happen.

  1. The test fails. Stack trace:
org.opentest4j.AssertionFailedError: Expected java.lang.IllegalArgumentException to be thrown, but nothing was thrown.
    at app//org.junit.jupiter.api.AssertionFailureBuilder.build(AssertionFailureBuilder.java:152)
    at app//org.junit.jupiter.api.AssertThrows.assertThrows(AssertThrows.java:73)
    at app//org.junit.jupiter.api.AssertThrows.assertThrows(AssertThrows.java:35)
    at app//org.junit.jupiter.api.Assertions.assertThrows(Assertions.java:3128)
    at app//PropertyLimiterQuestion2.PropertyValueLimiterTest.bind_invalidValue_MWE(PropertyValueLimiterTest.java:21)
    at java.base@17.0.13/java.lang.reflect.Method.invoke(Method.java:569)
    at java.base@17.0.13/java.util.ArrayList.forEach(ArrayList.java:1511)
    at java.base@17.0.13/java.util.ArrayList.forEach(ArrayList.java:1511)
  1. Junit5 tells me that an exception corresponding to the one I expected was raised: Exception in thread "Test worker" java.lang.IllegalArgumentException (full stacktrace below).

Given #2, I know that my expected exception has been raised, so why does the test fail?

Full stack trace for #2:

Exception in thread "Test worker" java.lang.IllegalArgumentException: expected exception
    at PropertyLimiterQuestion2.PropertyValueLimiterTest.lambda$bind_invalidValue_MWE$0(PropertyValueLimiterTest.java:17)
    at javafx.base/com.sun.javafx.binding.ExpressionHelper$SingleChange.fireValueChangedEvent(ExpressionHelper.java:181)
    at javafx.base/com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:80)
    at javafx.base/javafx.beans.property.ObjectPropertyBase.fireValueChangedEvent(ObjectPropertyBase.java:106)
    at javafx.base/javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:113)
    at javafx.base/javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:147)
    at javafx.base/javafx.beans.property.ObjectProperty.setValue(ObjectProperty.java:78)
    at PropertyLimiterQuestion2.PropertyValueLimiterTest.lambda$bind_invalidValue_MWE$1(PropertyValueLimiterTest.java:22)
    at org.junit.jupiter.api.AssertThrows.assertThrows(AssertThrows.java:53)
    at org.junit.jupiter.api.AssertThrows.assertThrows(AssertThrows.java:35)
    at org.junit.jupiter.api.Assertions.assertThrows(Assertions.java:3128)
    at PropertyLimiterQuestion2.PropertyValueLimiterTest.bind_invalidValue_MWE(PropertyValueLimiterTest.java:21)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:569)
    at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:766)
    at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131)
    at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:156)
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:147)
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:86)
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(InterceptingExecutableInvoker.java:103)
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.lambda$invoke$0(InterceptingExecutableInvoker.java:93)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:106)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:64)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:45)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:37)
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.invoke(InterceptingExecutableInvoker.java:92)
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.invoke(InterceptingExecutableInvoker.java:86)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$8(TestMethodTestDescriptor.java:217)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:213)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:138)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:68)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:156)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:146)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:144)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:143)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:100)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:160)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:146)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:144)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:143)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:100)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:160)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:146)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:144)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:143)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:100)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:198)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:169)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:93)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:58)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:141)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:57)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:103)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:85)
    at org.junit.platform.launcher.core.DelegatingLauncher.execute(DelegatingLauncher.java:47)
    at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.processAllTestClasses(JUnitPlatformTestClassProcessor.java:124)
    at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.access$000(JUnitPlatformTestClassProcessor.java:99)
    at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor.stop(JUnitPlatformTestClassProcessor.java:94)
    at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.stop(SuiteTestClassProcessor.java:63)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:569)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
    at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:92)
    at jdk.proxy1/jdk.proxy1.$Proxy4.stop(Unknown Source)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker$3.run(TestWorker.java:200)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.executeAndMaintainThreadName(TestWorker.java:132)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:103)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:63)
    at org.gradle.process.internal.worker.child.ActionExecutionWorker.execute(ActionExecutionWorker.java:56)
    at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:121)
    at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:71)
    at worker.org.gradle.process.internal.worker.GradleWorkerMain.run(GradleWorkerMain.java:69)
    at worker.org.gradle.process.internal.worker.GradleWorkerMain.main(GradleWorkerMain.java:74)
Solution

  • The listener isn't an appropriate place to validate the value provided. The fire event handler for the property change catches any exception raised by your listener, and reports to the current uncaught exception handler which in this case just prints the exception detail as you have shown and then continues without propagating any exception.

    See the relevant implementation of the fireValueChangedEvent() method of the SingleChange<T> class (which is used to handle the change events):

    @Override
protected void fireValueChangedEvent() {
    final T oldValue = currentValue;
    currentValue = observable.getValue();
    final boolean changed = (currentValue == null)? (oldValue != null) : !currentValue.equals(oldValue);
    if (changed) {
        try {
            listener.changed(observable, oldValue, currentValue);
        } catch (Exception e) {
             Thread.currentThread().getUncaughtExceptionHandler().uncaughtException(Thread.currentThread(), e);
        }
    }
}