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Check that JUnit Extension throws specific Exception

Suppose I develop an extension which disallows test method names to start with an uppercase character.
public class DisallowUppercaseLetterAtBeginning implements BeforeEachCallback {
#Override
public void beforeEach(ExtensionContext context) {
char c = context.getRequiredTestMethod().getName().charAt(0);
if (Character.isUpperCase(c)) {
throw new RuntimeException("test method names should start with lowercase.");
}
}
}
Now I want to test that my extension works as expected.
#ExtendWith(DisallowUppercaseLetterAtBeginning.class)
class MyTest {
#Test
void validTest() {
}
#Test
void TestShouldNotBeCalled() {
fail("test should have failed before");
}
}
How can I write a test to verify that the attempt to execute the second method throws a RuntimeException with a specific message?

Another approach could be to use the facilities provided by the new JUnit 5 - Jupiter framework.
I put below the code which I tested with Java 1.8 on Eclipse Oxygen. The code suffers from a lack of elegance and conciseness but could hopefully serve as a basis to build a robust solution for your meta-testing use case.
Note that this is actually how JUnit 5 is tested, I refer you to the unit tests of the Jupiter engine on Github.
public final class DisallowUppercaseLetterAtBeginningTest {
#Test
void testIt() {
// Warning here: I checked the test container created below will
// execute on the same thread as used for this test. We should remain
// careful though, as the map used here is not thread-safe.
final Map<String, TestExecutionResult> events = new HashMap<>();
EngineExecutionListener listener = new EngineExecutionListener() {
#Override
public void executionFinished(TestDescriptor descriptor, TestExecutionResult result) {
if (descriptor.isTest()) {
events.put(descriptor.getDisplayName(), result);
}
// skip class and container reports
}
#Override
public void reportingEntryPublished(TestDescriptor testDescriptor, ReportEntry entry) {}
#Override
public void executionStarted(TestDescriptor testDescriptor) {}
#Override
public void executionSkipped(TestDescriptor testDescriptor, String reason) {}
#Override
public void dynamicTestRegistered(TestDescriptor testDescriptor) {}
};
// Build our test container and use Jupiter fluent API to launch our test. The following static imports are assumed:
//
// import static org.junit.platform.engine.discovery.DiscoverySelectors.selectClass
// import static org.junit.platform.launcher.core.LauncherDiscoveryRequestBuilder.request
JupiterTestEngine engine = new JupiterTestEngine();
LauncherDiscoveryRequest request = request().selectors(selectClass(MyTest.class)).build();
TestDescriptor td = engine.discover(request, UniqueId.forEngine(engine.getId()));
engine.execute(new ExecutionRequest(td, listener, request.getConfigurationParameters()));
// Bunch of verbose assertions, should be refactored and simplified in real code.
assertEquals(new HashSet<>(asList("validTest()", "TestShouldNotBeCalled()")), events.keySet());
assertEquals(Status.SUCCESSFUL, events.get("validTest()").getStatus());
assertEquals(Status.FAILED, events.get("TestShouldNotBeCalled()").getStatus());
Throwable t = events.get("TestShouldNotBeCalled()").getThrowable().get();
assertEquals(RuntimeException.class, t.getClass());
assertEquals("test method names should start with lowercase.", t.getMessage());
}
Though a little verbose, one advantage of this approach is it doesn't require mocking and execute the tests in the same JUnit container as will be used later for real unit tests.
With a bit of clean-up, a much more readable code is achievable. Again, JUnit-Jupiter sources can be a great source of inspiration.

If the extension throws an exception then there's not much a #Test method can do since the test runner will never reach the #Test method. In this case, I think, you have to test the extension outside of its use in the normal test flow i.e. let the extension be the SUT.
For the extension provided in your question, the test might be something like this:
#Test
public void willRejectATestMethodHavingANameStartingWithAnUpperCaseLetter() throws NoSuchMethodException {
ExtensionContext extensionContext = Mockito.mock(ExtensionContext.class);
Method method = Testable.class.getMethod("MethodNameStartingWithUpperCase");
Mockito.when(extensionContext.getRequiredTestMethod()).thenReturn(method);
DisallowUppercaseLetterAtBeginning sut = new DisallowUppercaseLetterAtBeginning();
RuntimeException actual =
assertThrows(RuntimeException.class, () -> sut.beforeEach(extensionContext));
assertThat(actual.getMessage(), is("test method names should start with lowercase."));
}
#Test
public void willAllowTestMethodHavingANameStartingWithAnLowerCaseLetter() throws NoSuchMethodException {
ExtensionContext extensionContext = Mockito.mock(ExtensionContext.class);
Method method = Testable.class.getMethod("methodNameStartingWithLowerCase");
Mockito.when(extensionContext.getRequiredTestMethod()).thenReturn(method);
DisallowUppercaseLetterAtBeginning sut = new DisallowUppercaseLetterAtBeginning();
sut.beforeEach(extensionContext);
// no exception - good enough
}
public class Testable {
public void MethodNameStartingWithUpperCase() {
}
public void methodNameStartingWithLowerCase() {
}
}
However, your question suggests that the above extension is only an example so, more generally; if your extension has a side effect (e.g. sets something in an addressable context, populates a System property etc) then your #Test method could assert that this side effect is present. For example:
public class SystemPropertyExtension implements BeforeEachCallback {
#Override
public void beforeEach(ExtensionContext context) {
System.setProperty("foo", "bar");
}
}
#ExtendWith(SystemPropertyExtension.class)
public class SystemPropertyExtensionTest {
#Test
public void willSetTheSystemProperty() {
assertThat(System.getProperty("foo"), is("bar"));
}
}
This approach has the benefit of side stepping the potentially awkward setup steps of: creating the ExtensionContext and populating it with the state required by your test but it may come at the cost of limiting the test coverage since you can really only test one outcome. And, of course, it is only feasible if the extension has a side effect which can be evaulated in a test case which uses the extension.
So, in practice, I suspect you might need a combination of these approaches; for some extensions the extension can be the SUT and for others the extension can be tested by asserting against its side effect(s).

After trying the solutions in the answers and the question linked in the comments, I ended up with a solution using the JUnit Platform Launcher.
class DisallowUppercaseLetterAtBeginningTest {
#Test
void should_succeed_if_method_name_starts_with_lower_case() {
TestExecutionSummary summary = runTestMethod(MyTest.class, "validTest");
assertThat(summary.getTestsSucceededCount()).isEqualTo(1);
}
#Test
void should_fail_if_method_name_starts_with_upper_case() {
TestExecutionSummary summary = runTestMethod(MyTest.class, "InvalidTest");
assertThat(summary.getTestsFailedCount()).isEqualTo(1);
assertThat(summary.getFailures().get(0).getException())
.isInstanceOf(RuntimeException.class)
.hasMessage("test method names should start with lowercase.");
}
private TestExecutionSummary runTestMethod(Class<?> testClass, String methodName) {
SummaryGeneratingListener listener = new SummaryGeneratingListener();
LauncherDiscoveryRequest request = request().selectors(selectMethod(testClass, methodName)).build();
LauncherFactory.create().execute(request, listener);
return listener.getSummary();
}
#ExtendWith(DisallowUppercaseLetterAtBeginning.class)
static class MyTest {
#Test
void validTest() {
}
#Test
void InvalidTest() {
fail("test should have failed before");
}
}
}
JUnit itself will not run MyTest because it is an inner class without #Nested. So there are no failing tests during the build process.
Update
JUnit itself will not run MyTest because it is an inner class without #Nested. So there are no failing tests during the build process.
This is not completly correct. JUnit itself would also run MyTest, e.g. if "Run All Tests" is started within the IDE or within a Gradle build.
The reason why MyTest was not executed is because I used Maven and I tested it with mvn test. Maven uses the Maven Surefire Plugin to execute tests. This plugin has a default configuration which excludes all nested classes like MyTest.
See also this answer about "Run tests from inner classes via Maven" and the linked issues in the comments.

JUnit 5.4 introduced the JUnit Platform Test Kit which allows you to execute a test plan and inspect the results.
To take a dependency on it from Gradle, it might look something like this:
testImplementation("org.junit.platform:junit-platform-testkit:1.4.0")
And using your example, your extension test could look something like this:
import org.junit.jupiter.api.extension.ExtendWith
import org.junit.jupiter.api.fail
import org.junit.platform.engine.discovery.DiscoverySelectors
import org.junit.platform.testkit.engine.EngineTestKit
import org.junit.platform.testkit.engine.EventConditions
import org.junit.platform.testkit.engine.TestExecutionResultConditions
internal class DisallowUpperCaseExtensionTest {
#Test
internal fun `succeed if starts with lower case`() {
val results = EngineTestKit
.engine("junit-jupiter")
.selectors(
DiscoverySelectors.selectMethod(ExampleTest::class.java, "validTest")
)
.execute()
results.tests().assertStatistics { stats ->
stats.finished(1)
}
}
#Test
internal fun `fail if starts with upper case`() {
val results = EngineTestKit
.engine("junit-jupiter")
.selectors(
DiscoverySelectors.selectMethod(ExampleTest::class.java, "TestShouldNotBeCalled")
)
.execute()
results.tests().assertThatEvents()
.haveExactly(
1,
EventConditions.finishedWithFailure(
TestExecutionResultConditions.instanceOf(java.lang.RuntimeException::class.java),
TestExecutionResultConditions.message("test method names should start with lowercase.")
)
)
}
#ExtendWith(DisallowUppercaseLetterAtBeginning::class)
internal class ExampleTest {
#Test
fun validTest() {
}
#Test
fun TestShouldNotBeCalled() {
fail("test should have failed before")
}
}
}

JUnit5 - How to get test result in AfterTestExecutionCallback

I write JUnit5 Extension. But I cannot find way how to obtain test result.
Extension looks like this:
import org.junit.jupiter.api.extension.AfterTestExecutionCallback;
import org.junit.jupiter.api.extension.TestExtensionContext;
public class TestResultExtension implements AfterTestExecutionCallback {
#Override
public void afterTestExecution(TestExtensionContext context) throws Exception {
//How to get test result? SUCCESS/FAILED
}
}
Any hints how to obtain test result?

This work for me:
public class RunnerExtension implements AfterTestExecutionCallback {
#Override
public void afterTestExecution(ExtensionContext context) throws Exception {
Boolean testResult = context.getExecutionException().isPresent();
System.out.println(testResult); //false - SUCCESS, true - FAILED
}
}
#ExtendWith(RunnerExtension.class)
public abstract class Tests {
}

As other answers point out, JUnit communicates failed tests with exceptions, so an AfterTestExecutionCallback can be used to gleam what happened. Note that this is error prone as extension running later might still fail the test.
Another way to do that is to register a custom TestExecutionListener. Both of these approaches are a little roundabout, though. There is an issue that tracks a specific extension point for reacting to test results, which would likely be the most straight-forward answer to your question. If you can provide a specific use case, it would be great if you could head over to #542 and leave a comment describing it.

You can use SummaryGeneratingListener from org.junit.platform.launcher.listeners
It contains MutableTestExecutionSummary field, which implements TestExecutionSummary interface, and this way you can obtain info about containers, tests, time, failures etc.
You can create custom listener, for example:
Create class that extends SummaryGeneratingListener
public class ResultAnalyzer extends SummaryGeneratingListener {
#Override
public void testPlanExecutionFinished(TestPlan testPlan) {
//This method is invoked after all tests in all containers is finished
super.testPlanExecutionFinished(testPlan);
analyzeResult();
}
private void analyzeResult() {
var summary = getSummary();
var failures = summary.getFailures();
//Do something
}
}
Register listener by creating file
src\main\resources\META-INF\services\org.junit.platform.launcher.TestExecutionListener
and specify your implementation in it
path.to.class.ResultAnalyzer
Enable auto-detection of extensions, set parameter
-Djunit.jupiter.extensions.autodetection.enabled=true
And that's it!
Docs
https://junit.org/junit5/docs/5.0.0/api/org/junit/platform/launcher/listeners/SummaryGeneratingListener.html
https://junit.org/junit5/docs/5.0.0/api/org/junit/platform/launcher/listeners/TestExecutionSummary.html
https://junit.org/junit5/docs/current/user-guide/#extensions-registration-automatic

I have only this solution:
String testResult = context.getTestException().isPresent() ? "FAILED" : "OK";
It seems that it works well. But I am not sure if it will work correctly in all situations.

Fails in JUnit are propagated with exceptions. There are several exceptions, which indicate various types of errors.
So an exception in TestExtensionContext#getTestException() indicates an error. The method can't manipulate actual test results, so depending on your use case you might want to implement TestExecutionExceptionHandler, which allows you to swallow exceptions, thus changing whether a test succeeded or not.

You're almost there.
To implement a test execution callback and get the test result for logging (or generating a report) you can do the following:
import org.junit.jupiter.api.extension.AfterTestExecutionCallback;
import org.junit.jupiter.api.extension.ExtensionContext;
public class TestResultExtension implements AfterTestExecutionCallback
{
#Override
public void afterTestExecution(ExtensionContext context) throws Exception
{
// check the context for an exception
Boolean passed = context.getExecutionException().isEmpty();
// if there isn't, the test passed
String result = passed ? "PASSED" : "FAILED";
// now that you have the result, you can do whatever you want
System.out.println("Test Result: " + context.getDisplayName() + " " + result);
}
}
And then you just add the TestResultExtension using the #ExtendWith() annotation for your test cases:
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import static org.junit.jupiter.api.Assertions.assertTrue;
#ExtendWith(TestResultExtension.class)
public class SanityTest
{
#Test
public void testSanity()
{
assertTrue(true);
}
#Test
public void testInsanity()
{
assertTrue(false);
}
}
It's a good idea to extend a base test that includes the extension
import org.junit.jupiter.api.extension.ExtendWith;
#ExtendWith(TestResultExtension.class)
public class BaseTest
{}
And then you don't need to include the annotation in every test:
public class SanityTest extends BaseTest
{ //... }

How to use JUnit4TestAdapter with objects

I am trying to write a test suite using JUnit4 by relying on JUnit4TestAdapter. Having a look at the code of this class I saw that it only works with a Class as input. I would like to build a test class and set a parameter on it before running it with my TestSuite. Unfortunately, Junit4TestAdapter is building the test by using reflection (not 100% sure about the mechanism behind it), which means that I cannot change my test class on runtime.
Has anybody done anything similar before? Is there any possible workaround to this issue? Thanks for your help!
public class SimpleTest {
#Test
public void testBasic() {
TemplateTester tester = new TemplateTester();
ActionIconsTest test = new ActionIconsTest();
test.setParameter("New Param Value");
tester.addTests(test);
tester.run();
}
}
/////
public class TemplateTester {
private TestSuite suite;
public TemplateTester() {
suite = new TestSuite();
}
public void addTests(TemplateTest... tests) {
for (TemplateTest test : tests) {
suite.addTest(new JUnit4TestAdapter(test.getClass()));
}
}
public void run() {
suite.run(new TestResult());
}
}
/////
public interface TemplateTest {
}
/////
public class ActionIconsTest extends BaseTestStrategy implements TemplateTest {
#Test
public void icons() {
//Test logic here
}
public void navigateToTestPage() {
//Here I need the parameter
}
}
/////
public abstract class BaseTestStrategy {
protected String parameter;
#Before
public void init() {
navigateToTestPage();
}
public abstract void navigateToTestPage();
public void setParameter(String parameter) {
this.parameter = parameter;
}
}
I am trying to test a web application with Selenium. The way I want to test is by splitting the functionality, e.g., I want to test the available icons (ActionIconsTest), then I'd like to test other parts like buttons, etc.
The idea behind this is to have a better categorization of the functionality available in certain screen. This is quite coupled with the way we are currently developing our web app.
With this in mind, TemplateTest is just an interface implemented by the different kind of tests (ActionIconTest, ButtonTest, etc) available in my system.
TemplateTester is a Junit suite test with all the different tests that implement the interface TemplateTest.
The reason for this question is because I was trying to implement a Strategy pattern and then realized of the inconvenient of passing a class to Junit4TestAdapter in runtime.

Well, taking in account that JUNIT needs your tester's Class object as an object factory (so he can create several instances of your tester), I can only suggest you pass parameters to your tester through System Properties.
Moreover, it's the recommended way of passing parameters: http://junit.org/faq.html#running_7

Mockito not resetting

I have a tests, that when they run individually work fine. However when i run them together one always fail expecting total invocations accross both tests rather than one.
I have added Mockito.reset in the before and after method, but to no avail.
private Logic mockTest = Mockito.mock(Logic.class);
#Before
public void createMocks() {
Mockito.reset(mockTest);
}
#Test
public void TestGameList() {
Mockito.when(mockTest.getGame()).thenReturn(null);
Mockito.verify(mockTest, Mockito.times(1)).getGame();
}
#Test
public void TestGame2List() {
Mockito.when(mockTest.getGame()).thenReturn(null);
Mockito.verify(mockTest, Mockito.times(1)).getGame();
}
Why doesnt reset work?
I have tried VerificationModeFactory to count it, but that doesnt work either

Use one of the following:
#Mock
private Logic mockTest;
#Before
public void createMocks() {
MockitoAnnotiation.initMocks(this);
}
or
private Logic mockTest;
#Before
public void createMocks() {
mockTest = Mockito.mock(Logic.class);
}
Either way you will create an entirely new mock for each test thereby ensuring that no state is maintained across tests.

How to disable TestNG test based on a condition

Is there currently a way to disable TestNG test based on a condition
I know you can currently disable test as so in TestNG:
#Test(enabled=false, group={"blah"})
public void testCurrency(){
...
}
I will like to disable the same test based on a condition but dont know how. something Like this:
#Test(enabled={isUk() ? false : true), group={"blah"})
public void testCurrency(){
...
}
Anyone has a clue on whether this is possible or not.

An easier option is to use the #BeforeMethod annotation on a method which checks your condition. If you want to skip the tests, then just throw a SkipException. Like this:
#BeforeMethod
protected void checkEnvironment() {
if (!resourceAvailable) {
throw new SkipException("Skipping tests because resource was not available.");
}
}

You have two options:
Implement an annotation transformer.
Use BeanShell.
Your annotation transformer would test the condition and then override the #Test annotation to add the attribute "enabled=false" if the condition is not satisfied.

There are two ways that I know of that allow you the control of "disabling" tests in TestNG.
The differentiation that is very important to note is that SkipException will break out off all subsequent tests while implmenting IAnnotationTransformer uses Reflection to disbale individual tests, based on a condition that you specify. I will explain both SkipException and IAnnotationTransfomer.
SKIP Exception example
import org.testng.*;
import org.testng.annotations.*;
public class TestSuite
{
// You set this however you like.
boolean myCondition;
// Execute before each test is run
#BeforeMethod
public void before(Method methodName){
// check condition, note once you condition is met the rest of the tests will be skipped as well
if(myCondition)
throw new SkipException();
}
#Test(priority = 1)
public void test1(){}
#Test(priority = 2)
public void test2(){}
#Test(priority = 3)
public void test3(){}
}
IAnnotationTransformer example
A bit more complicated but the idea behind it is a concept known as Reflection.
Wiki - http://en.wikipedia.org/wiki/Reflection_(computer_programming)
First implement the IAnnotation interface, save this in a *.java file.
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import org.testng.IAnnotationTransformer;
import org.testng.annotations.ITestAnnotation;
public class Transformer implements IAnnotationTransformer {
// Do not worry about calling this method as testNG calls it behind the scenes before EVERY method (or test).
// It will disable single tests, not the entire suite like SkipException
public void transform(ITestAnnotation annotation, Class testClass, Constructor testConstructor, Method testMethod){
// If we have chose not to run this test then disable it.
if (disableMe()){
annotation.setEnabled(false);
}
}
// logic YOU control
private boolean disableMe() {
}
}
Then in you test suite java file do the following in the #BeforeClass function
import org.testng.*;
import org.testng.annotations.*;
/* Execute before the tests run. */
#BeforeClass
public void before(){
TestNG testNG = new TestNG();
testNG.setAnnotationTransformer(new Transformer());
}
#Test(priority = 1)
public void test1(){}
#Test(priority = 2)
public void test2(){}
#Test(priority = 3)
public void test3(){}
One last step is to ensure that you add a listener in your build.xml file.
Mine ended up looking like this, this is just a single line from the build.xml:
<testng classpath="${test.classpath}:${build.dir}" outputdir="${report.dir}"
haltonfailure="false" useDefaultListeners="true"
listeners="org.uncommons.reportng.HTMLReporter,org.uncommons.reportng.JUnitXMLReporter,Transformer"
classpathref="reportnglibs"></testng>

I prefer this annotation based way for disable/skip some tests based on environment settings. Easy to maintain and not requires any special coding technique.
Using the IInvokedMethodListener interface
Create a custom anntotation e.g.: #SkipInHeadlessMode
Throw SkipException
public class ConditionalSkipTestAnalyzer implements IInvokedMethodListener {
protected static PropertiesHandler properties = new PropertiesHandler();
#Override
public void beforeInvocation(IInvokedMethod invokedMethod, ITestResult result) {
Method method = result.getMethod().getConstructorOrMethod().getMethod();
if (method == null) {
return;
}
if (method.isAnnotationPresent(SkipInHeadlessMode.class)
&& properties.isHeadlessMode()) {
throw new SkipException("These Tests shouldn't be run in HEADLESS mode!");
}
}
#Override
public void afterInvocation(IInvokedMethod iInvokedMethod, ITestResult iTestResult) {
//Auto generated
}
}
Check for the details:
https://www.lenar.io/skip-testng-tests-based-condition-using-iinvokedmethodlistener/

A Third option also can be Assumption
Assumptions for TestNG - When a assumption fails, TestNG will be instructed to ignore the test case and will thus not execute it.
Using the #Assumption annotation
Using AssumptionListener Using the Assumes.assumeThat(...)
method
You can use this example: Conditionally Running Tests In TestNG

Throwing a SkipException in a method annotated with #BeforeMethod did not work for me because it skipped all the remaining tests of my test suite with no regards if a SkipException were thrown for those tests.
I did not investigate it thoroughly but I found another way : using the dependsOnMethods attribute on the #Test annotation:
import org.testng.SkipException;
import org.testng.annotations.Test;
public class MyTest {
private boolean conditionX = true;
private boolean conditionY = false;
#Test
public void isConditionX(){
if(!conditionX){
throw new SkipException("skipped because of X is false");
}
}
#Test
public void isConditionY(){
if(!conditionY){
throw new SkipException("skipped because of Y is false");
}
}
#Test(dependsOnMethods="isConditionX")
public void test1(){
}
#Test(dependsOnMethods="isConditionY")
public void test2(){
}
}

SkipException: It's useful in case of we have only one #Test method in the class. Like for Data Driven Framework, I have only one Test method which need to either executed or skipped on the basis of some condition. Hence I've put the logic for checking the condition inside the #Test method and get desired result.
It helped me to get the Extent Report with test case result as Pass/Fail and particular Skip as well.