Launching JUnit jupiter tests from inside a main method? - junit

Question

I have a Java class with a main method that I invoke to occasionally run some tests. Specifically, I'm trying to come up with a solution for quickly testing various code snippets that use the AWS SDK to create/read some S3 objects. I'm not really trying to build regular unit/integration tests, and I'm not interested in mocking the S3 code. I'm trying to quickly develop/debug some code using a test framework. I found the following SO question, and the answer about using JUnit5 Jupiter's Launcher and it intrigued me:
How do I run JUnit tests from inside my java application?
So I read the Junit5 chapter on the Launcher API and followed the example code. I came up with something like this:
class S3ManualTest {
public static void main(String[] args) {
LauncherDiscoveryRequest request =
LauncherDiscoveryRequestBuilder
.request()
.selectors(selectPackage("com.xyz.s3util"),
selectClass(S3ManualTest.class),
selectMethod(S3ManualTest.class, "happyPath")
)
.build();
Launcher launcher = LauncherFactory.create();
SummaryGeneratingListener listener = new SummaryGeneratingListener();
launcher.execute(request, listener);
TestExecutionSummary summary = listener.getSummary();
System.out.println("# of containers found: " + summary.getContainersFoundCount());
System.out.println("# of containers skipped: " + summary.getContainersSkippedCount());
System.out.println("# of tests found: " + summary.getTestsFoundCount());
System.out.println("# of tests skipped: " + summary.getTestsSkippedCount());
}
void happyPath() {
assertTrue(true); // Do useful stuff here
}
}
The launcher doesn't find any tests to run, even though I specifically selected the "happyPath" method. I have tried annotating the happyPath() method with #Test, and that seems to work, but it also has the undesired side effect that the method gets executed if I run all tests in that package, either from gradle, or from inside the IDE. Essentially, I want my test methods to be invoked with the JUnit5 framework, but only when I manually run the main method in the class. I was thinking about some custom annotations, or implementing some interface that would get picked up by the test engine, but haven't gone down that route yet. I'm guessing there's some easy way of accomplishing what I'm trying to do. Thanks.

Answer 1

I could only find a work around: disabling the happyPath() test method by default and override it in your program like explained here: https://junit.org/junit5/docs/current/user-guide/#extensions-conditions-deactivation
#Test
#Disabled
void happyPath() {
assertTrue(true); // Do useful stuff here
}
And in your launcher setup, deactivate the DisabledCondition:
LauncherDiscoveryRequest request = LauncherDiscoveryRequestBuilder
.request()
.selectors(selectMethod(S3ManualTest.class, "happyPath"))
.configurationParameter(
"junit.jupiter.conditions.deactivate",
"org.junit.*DisabledCondition")
.build();
You may also specify a dedicated switch, if you don't want deactivate DisabledCondition for the entire run:
#Test
#EnabledIf("'true'.equals(junitConfigurationParameter.get('manual'))")
void happyPath() {
assertTrue(true); // Do useful stuff here
}
with
LauncherDiscoveryRequest request = LauncherDiscoveryRequestBuilder
...
.configurationParameter("manual", "true")
.build();
The second work-around, if applied to more then a few methods, screams for a dedicated ExecutionCondition extension. See details at https://junit.org/junit5/docs/current/user-guide/#writing-tests-conditional-execution-scripts