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How to write spock test case for exception handling?

I am learning Spock so this may be very basic.
public Random genRand() {
try {
return SecureRandom.getInstanceStrong();
}
catch (NoSuchAlgorithmException e) {
logger.debug(e.getMessage());
return new SecureRandom();
}
}
What I have tried so far is:
public void setup() {
mockClassName = spy(ClassName)
mockClassName.logger() >> mockLogger
}
def "exception test case"() {
given: "nothing"
when:"method call happens"
mockClassName.genRand()
then:"handle"
SecureRandom.getInstanceStrong()
}
This covers the try block only.
While trying:
public void setup() {
mockClassName = spy(ClassName)
mockClassName.logger() >> mockLogger
}
def "exception test case"() {
given: "nothing"
SecureRandom.getInstanceStrong() >> Exception
when:"method call happens"
mockClassName.genRand()
then:"catch"
NoSuchAlgorithmException e = thrown()
new SecureRandom()
}
This gives the error, expected exception of type java.security.NoSuchAlgorithmException, but no exception was thrown.
Is it possible to do both try and catch in one test case? Feel free to make two.

You should not try to test several branches of your code in one test, so doing it in two tests is actually the right approach. If you try to find a simple description of your test and have to describe several kinds of results, then that's a hint that your approach is not good.
A reminder, you should name your test methods with "It...", for example:
"It returns a default SecureRandom, if no strong instance of SecureRandom can be found"
Another point: You code never leaks a NoSuchAlgorithmException into Spec. This exception is caught in your production code, and then you retunr a valid SecureRandom. You can only use thrown() if your code actually throws an exception, meaning this is a hard expectation. Your test will fail if the exception is not thrown.

Quoting my own comment:
Why don't you want to change the application code in order to make it more testable? You could factor out the SecureRandom.getInstanceStrong() call into an extra method, calling it from genRand(), handling the exception there like before. Then you could stub that method in a spy for the error case, throwing an exception instead of returning a result. That would give you full coverage of all execution paths without the need to mock static methods of JDK classes.
I mean something like this:
package de.scrum_master.stackoverflow.q74797317;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Random;
public class RandomProvider {
public Random genRand() {
try {
return getRandStrong();
}
catch (NoSuchAlgorithmException e) {
System.err.println(e.getMessage());
return new SecureRandom();
}
}
protected SecureRandom getRandStrong() throws NoSuchAlgorithmException {
return SecureRandom.getInstanceStrong();
}
}
package de.scrum_master.stackoverflow.q74797317
import spock.lang.Specification
import java.security.NoSuchAlgorithmException
class RandomProviderTest extends Specification {
def "happy path"() {
given:
RandomProvider randomProvider = new RandomProvider()
expect:
randomProvider.genRand()
}
def "exception test case"() {
given:
RandomProvider randomProvider = Spy() {
getRandStrong() >> { throw new NoSuchAlgorithmException("oops") }
}
expect:
randomProvider.genRand()
}
}
Try it in the Groovy Web Console.
In my IDE, the coverage view looks like this:

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 get the exception that was thrown when a Cucumber test failed in Java?

I can perform actions on test failure by using:
#After
public void afterTest(Scenario scenario) {
if (scenario.isFailed()) {
/*Do stuff*/
}
}
However some of the actions I need to perform depend on the Exception that was thrown and in what context it was thrown. Is there a way to get the Throwable that caused the test to fail? For example in JUnit I would do this by extending TestWatcher and add a rule to my tests:
#Override
protected void failed(Throwable e, Description description) {
/*Do stuff with e*/
}
However the cucumber-junit iplementation does not allow the use of rules, so this solution would not work with Cucumber.
I don't think I need to explain why accessing a thrown exception on test failure would be useful, however I will still provide an Example:
My test environment is not always stable, so my tests might fail unexpectedly at any moment (there's no specific place I can try to catch the exception since it could occur at any time). When this happens I need the test to reschedule for another attempt, and log the incident so that we can get some good statistical data on the environment instability (when, how frequent, how long etc.)

The problem with the work around suggested by Frank Escobar:
By using reflection to reach into a frameworks internals you're depending on implementation details. This is a bad practice, when ever the framework changes its implementation your code may break as you will observe in Cucumber v5.0.0.
Hooks in Cucumber are designed to manipulate the test execution context before and after a scenario. They're not made to report on the test execution itself. Reporting is cross cutting concern and best managed by using the plugin system.
For example:
package com.example;
import io.cucumber.plugin.ConcurrentEventListener;
import io.cucumber.plugin.event.EventPublisher;
import io.cucumber.plugin.event.Result;
import io.cucumber.plugin.event.Status;
import io.cucumber.plugin.event.TestCase;
import io.cucumber.plugin.event.TestCaseFinished;
public class MyTestListener implements ConcurrentEventListener {
#Override
public void setEventPublisher(EventPublisher publisher) {
publisher.registerHandlerFor(TestCaseFinished.class, this::handleTestCaseFinished);
}
private void handleTestCaseFinished(TestCaseFinished event) {
TestCase testCase = event.getTestCase();
Result result = event.getResult();
Status status = result.getStatus();
Throwable error = result.getError();
String scenarioName = testCase.getName();
String id = "" + testCase.getUri() + testCase.getLine();
System.out.println("Testcase " + id + " - " + status.name());
}
}
When using JUnit 4 and TestNG you can activate this plugin using:
#CucumberOptions(plugin="com.example.MyTestListener")
With JUnit 5 you add it to junit-platform.properties:
cucumber.plugin=com.example.MyTestListener
Or if you are using the CLI
--plugin com.example.MyTestListener

I've implemented this method using reflections. You can't access directly to steps errors (stack trace). I've created this static method which allows you to access to "stepResults" attribute and then you can iterate and get the error and do whatever you want.
import cucumber.runtime.ScenarioImpl;
import gherkin.formatter.model.Result;
import org.apache.commons.lang3.reflect.FieldUtils;
import java.lang.reflect.Field;
import java.util.ArrayList;
#After
public void afterScenario(Scenario scenario) {
if (scenario.isFailed())
logError(scenario);
}
private static void logError(Scenario scenario) {
Field field = FieldUtils.getField(((ScenarioImpl) scenario).getClass(), "stepResults", true);
field.setAccessible(true);
try {
ArrayList<Result> results = (ArrayList<Result>) field.get(scenario);
for (Result result : results) {
if (result.getError() != null)
LOGGER.error("Error Scenario: {}", scenario.getId(), result.getError());
}
} catch (Exception e) {
LOGGER.error("Error while logging error", e);
}
}

You can to this by writing your own custom implementation of Formatter & Reporter interface. The empty implementation of Formatter is the NullFormatter.java which you can extend. You will need to provide implementations for the Reporter interface.
The methods which would be of interest will be the result() of the Reporter interface and possibly the done() method of Formatter. The result() has the Result object which has the exceptions.
You can look at RerunFormatter.java for clarity.
Github Formatter source
public void result(Result result) {
//Code to create logs or store to a database etc...
result.getError();
result.getErrorMessage();
}
You will need to add this class(com.myimpl.CustomFormRep) to the plugin option.
plugin={"pretty", "html:report", "json:reports.json","rerun:target/rerun.txt",com.myimpl.CustomFormRep}
More details on custom formatters.
You can use the rerun plugin to get a list of failed scenarios to run again. Not sure about scheduling a run of failed tests, code to create a batch job or schedule one on your CI tool.

This is the workaround for cucumber-java version 4.8.0 using reflection.
import cucumber.api.Result;
import io.cucumber.core.api.Scenario;
import io.cucumber.core.logging.Logger;
import io.cucumber.core.logging.LoggerFactory;
import io.cucumber.java.After;
import org.apache.commons.lang3.ClassUtils;
import org.apache.commons.lang3.reflect.FieldUtils;
import java.io.IOException;
import java.lang.reflect.Field;
import java.net.URL;
import java.util.ArrayList;
#After
public void afterScenario(Scenario scenario) throws IOException {
if(!scenario.getStatus().isOk(true)){
logError(scenario);
}
}
private static void logError(Scenario scenario) {
try {
Class clasz = ClassUtils.getClass("cucumber.runtime.java.JavaHookDefinition$ScenarioAdaptor");
Field fieldScenario = FieldUtils.getField(clasz, "scenario", true);
fieldScenario.setAccessible(true);
Object objectScenario = fieldScenario.get(scenario);
Field fieldStepResults = objectScenario.getClass().getDeclaredField("stepResults");
fieldStepResults.setAccessible(true);
ArrayList<Result> results = (ArrayList<Result>) fieldStepResults.get(objectScenario);
for (Result result : results) {
if (result.getError() != null) {
LOGGER.error(String.format("Error Scenario: %s", scenario.getId()), result.getError());
}
}
} catch (Exception e) {
LOGGER.error("Error while logging error", e);
}
}

For cucumber-js https://www.npmjs.com/package/cucumber/v/6.0.3
import { After } from 'cucumber'
After(async function(scenario: any) {
const exception = scenario.result.exception
if (exception) {
this.logger.log({ level: 'error', message: '-----------StackTrace-----------' })
this.logger.log({ level: 'error', message: exception.stack })
this.logger.log({ level: 'error', message: '-----------End-StackTrace-----------' })
}
})

After a lot of experimentation I now removed the Before/After-Annotations and rely on Cucumber-Events instead. They contain the TestCase (which is what the Scenario-class wraps) and a Result where you can call getError(); to get the Throwable.
Here is a simple example to get it working
import io.cucumber.plugin.EventListener;
import io.cucumber.plugin.event.EventPublisher;
import io.cucumber.plugin.event.Result;
import io.cucumber.plugin.event.Status;
import io.cucumber.plugin.event.TestCase;
import io.cucumber.plugin.event.TestCaseFinished;
import io.cucumber.plugin.event.TestCaseStarted;
import org.openqa.selenium.WebDriver;
public class TestCaseListener implements EventListener {
#Override
public void setEventPublisher(final EventPublisher publisher) {
publisher.registerHandlerFor(TestCaseStarted.class, this::onTestCaseStarted);
publisher.registerHandlerFor(TestCaseFinished.class, this::onTestCaseFinished);
}
public void onTestCaseStarted(TestCaseStarted event) {
TestCase testCase = event.getTestCase();
System.out.println("Starting " + testCase.getName());
// Other stuff you did in your #Before-Method.
// ...
}
private void onTestCaseFinished(final TestCaseFinished event) {
TestCase testCase = event.getTestCase();
System.out.println("Finished " + testCase.getName());
Result result = event.getResult();
if (result.getStatus() == Status.FAILED) {
final Throwable error = result.getError();
error.printStackTrace();
}
// Other stuff you did in your #After-Method.
// ...
}
}
All that's left to do is to register this class as a Cucumber-Plugin.
I did this by modifying my #CucumberOptions-annotation:
#CucumberOptions(plugin = {"com.example.TestCaseListener"})
I find this much cleaner than all of this reflection-madness, however it requires a lot more code-changes.
Edit
I don't know why, but this caused a lot of tests to randomly fail in a multithreaded environment.
I tried to figure it out, but now also use the ugly reflections mentioned in this thread:
public class SeleniumUtils {
private static final Logger log = LoggerFactory.getLogger(SeleniumUtils.class);
private static final Field field = FieldUtils.getField(Scenario.class, "delegate", true);
private static Method getError;
public static Throwable getError(Scenario scenario) {
try {
final TestCaseState testCase = (TestCaseState) field.get(scenario);
if (getError == null) {
getError = MethodUtils.getMatchingMethod(testCase.getClass(), "getError");
getError.setAccessible(true);
}
return (Throwable) getError.invoke(testCase);
} catch (Exception e) {
log.warn("error receiving exception", e);
}
return null;
}
}

If you just want to massage the result being sent to the report then you can extend the CucumberJSONFormatter and override the result method like this:
public class CustomReporter extends CucumberJSONFormatter {
CustomReporter(Appendable out) {
super(out);
}
/**
* Truncate the error in the output to the testresult.json file.
* #param result the error result
*/
#Override
void result(Result result) {
String errorMessage = null;
if (result.error) {
errorMessage = "Error: " + truncateError(result.error);
}
Result myResult = new Result(result.status, result.duration, errorMessage);
// Log the truncated error to the JSON report
super.result(myResult);
}
}
Then set the plugin option to:
plugin = ["com.myimpl.CustomReporter:build/reports/json/testresult.json"]

Testing ClassNotFound Exception

I'm trying to test that a class is not found with UnitTest on Android.
What's going on:
1. I'm writing an android library with transitive dependencies which are resolved in the host application
2. The developer may remove some dependencies for example remove all com.example.package
3. I have a Factory that will try to instantiate (using reflection) an Object and catch the ClassNotFoundException. If the developer remove the dependencies, the exception should be thrown.
4. I want to test this case, but all I found is issue with dependencies, not how to test for it.
Example code I want to test
try {
sNetworkResponseBuilderClass = OkHttpNetworkResponse.Builder.class;
} catch (Exception e){
// <<<< I want to test this case
new ClassNotFoundException("Unable to find OkHttpNetworkResponse.Builder.class").printStackTrace();
return null;
}
library used: hamcrast, mockito, JUnit 4.
Do you know how to do it?

So for me the first thing you need to do is to extract the part of the code that can throw a ClassNotFoundException in order to be able to easily mock it, something like:
public Class<? extends NetworkResponseBuilder> getNetworkResponseBuilderClass()
throws ClassNotFoundException {
// Your logic here
}
Then you can test a real factory instance using Mockito.spy to be able to redefine the behavior of the method getNetworkResponseBuilderClass() as next:
public void testFactoryIfNetworkResponseBuilderNotFound() {
Factory factory = spy(new Factory());
when(factory.getNetworkResponseBuilderClass()).thenThrow(
new ClassNotFoundException()
);
// The rest of your test here
}
public void testFactoryIfNetworkResponseBuilderFound() {
Factory factory = spy(new Factory());
when(factory.getNetworkResponseBuilderClass()).thenReturn(
OkHttpNetworkResponse.Builder.class
);
// The rest of your test here
}
More details about Mockito.spy.

Not quite sure if I understood your question correctly, but you can check with JUnit if an exception gets thrown:
#Test(expected=ClassNotFoundException.class)
public void testClassNotFoundException() {
// a case where the exception gets thrown
}

OkHttpNetworkResponse.Builder might be as follows:
package com.example.model;
public class OkHttpNetworkResponse {
public static class Builder {
}
}
I have a Factory that will try to instantiate (using reflection) an Object and catch the ClassNotFoundException. If the developer remove
the dependencies, the exception should be thrown.
Factory Class: which will create any object might be as follows:
package com.example.factory;
public class Factory {
public static Object getInstance(String className)
throws ClassNotFoundException, InstantiationException,
IllegalAccessException {
Class clazz = Class.forName(className);
return clazz.newInstance();
}
}
The developer may remove some dependencies for example remove all com.example.package
I want to test this case, but all I found is issue with dependencies, not how to test for it.
FactoryTest Class: which will test whether ClassNotFoundException is thrown or not might be as follows: N.B: please Check the comments carefully.
package com.example.factory;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import java.io.File;
import java.io.IOException;
import org.junit.Test;
public class FactoryTest {
Factory factory;
#Test(expected=ClassNotFoundException.class)
public void test() throws IOException, ClassNotFoundException, InstantiationException, IllegalAccessException {
ClassLoader loader = FactoryTest.class.getClassLoader();
String directory = loader.getResource(".").getPath() + "/com/example/model";
File dir = new File(directory);
//Checking directory already existed or not..
assertTrue("Directory:"+dir.getPath()+" not exist",dir.exists());
//Deleting directory
deleteDirectoryProgramatically(directory);
//Checking directory already deleted or not..
assertFalse("Directory:"+dir.getPath()+" still exist",dir.exists());
//Now getInstance Method will throw ClassNotFoundException because OkHttpNetworkResponse.Builder.class has been deleted programatically.
Factory.getInstance("OkHttpNetworkResponse.Builder.class");
}
private void deleteDirectoryProgramatically(String directory) {
File dir = new File(directory);
System.out.println(dir.getAbsolutePath());
String[] files = dir.list();
for (String f : files) {
File fl = new File(directory,f);
System.out.println(f+ " deleted?"+fl.delete());
}
System.out.println(dir+ " deleted?"+dir.delete());
}
}

It is very simple issue. JUnit4 exception unit testing is given below with an example. Hope it will clarify you.
MyNumber.java
public class MyNumber {
int number;
public MyNumber div(MyNumber rhs) {
if (rhs.number == 0) throw new IllegalArgumentException("Cannot divide by 0!");
this.number /= rhs.number;
return this;
}
}
MyNumberTest.java
public class MyNumberTest {
private MyNumber number1, number2; // Test fixtures
#Test(expected = IllegalArgumentException.class)
public void testDivByZero() {
System.out.println("Run #Test testDivByZero"); // for illustration
number2.setNumber(0);
number1.div(number2);
}
}
JUnit - Exceptions Test
To test if the code throws a desired exception, use annotation #Test(expected = exception.class), as illustrated in the previous example. For your case it will be
/**
* Check for class not found exception
**/
#Test(expected=ClassNotFoundException.class)
public void testClassNotFoundException() {
.....
}
For better understanding, you can go through this tutorial: Java Unit
Testing - JUnit & TestNG. It contains full running code example
step by step with explanation.

inside catch you can check the object with the instanceof operator as :
try {
sNetworkResponseBuilderClass = OkHttpNetworkResponse.Builder.class;
} catch (Exception e){
if(e instanceof ClassNotFoundException){
// here you can do the code you want in case of ClassNotFoundException thrown
}
}

it is your dictionary problem. in your dictionary in test class will not have . change your dictionary.

Use Class.forName("com.example.ClassName")
try {
Class.forName("com.example.OkHttpNetworkResponse.Builder");
} catch (ClassNotFoundException e) {
// This class was not found
}
See Class.forName(String className)