Add Kotlin code examples to last writing tests topics by danil-pavlov · Pull Request #5898 · junit-team/junit-framework

danil-pavlov · 2026-07-22T10:39:19Z

Adds Kotlin tabbed code snippets to the last three topics in the Writing Tests section of the User Guide,
continuing the effort in #5853

Pages updated:

Tagging and Filtering
Test Execution Order
Parameterized Classes and Tests

I hereby agree to the terms of the JUnit Contributor License Agreement.

Definition of Done

There are no TODOs left in the code
Method preconditions are checked and documented in the method's Javadoc
Coding conventions (e.g. for logging) have been followed
Change is covered by automated tests including corner cases, errors, and exception handling
Public API has Javadoc and @API annotations
Change is documented in the User Guide and Release Notes

marcphilipp · 2026-07-30T10:28:05Z

+}
+
+// tag::parameter_resolution_factory_MethodSource_example[]
+fun factoryMethodWithArguments(quantity: Int): Stream<Arguments> =


This method isn't found like this, is it? Please run ./gradlew consoleLauncherTest to execute these new snippets.

I indeed missed these errors cause the weren't discoverable by our other test tasks. To fix the failing consoleLauncherTest, I went with the PER_CLASS approach, which also helped clean up extra tags and includes. But if you don't agree, I can try some other workaround

I think that's ok but we should add a note in the Kotlin tabs, below the code block, of all such snippets:

NOTE: For conciseness, this snippet assumes that the enclosing test classes used the `PER_CLASS` xref:writing-tests/test-instance-lifecycle.adoc[].

marcphilipp

Almost there!

marcphilipp · 2026-07-31T06:49:15Z

+    class Book(
+        val title: String
+    )


This is missing a @JvmStatic fromTitle() method.

Right, I was trying to avoid companion objects, but now that we use PER_CLASS for other examples in this file, I think it's OK to use it for just this one

marcphilipp · 2026-07-31T06:53:44Z

+ * https://www.eclipse.org/legal/epl-v20.html
+ */
+
+package example.kotlin


We should include the package declaration in the rendered snippet because it's referenced below. If that doesn't work due to the formatter, we can duplicate it in the adoc file.

Oh, I had it originally (24490a6), I guess it's the formatter problem

Signed-off-by: Danil Pavlov <danil.pavlov@jetbrains.com>

testlens-app · 2026-07-31T18:49:04Z

🚨 TestLens detected 4 failed tests 🚨

Here is what you can do:

Inspect the test failures carefully.
If you are convinced that some of the tests are flaky, you can mute them below.
Finally, trigger a rerun by checking the rerun checkbox.

Test Summary

CI / Build / Windows > :junit-vintage-engine:test_4_12

Test	Runs	Flakiness
ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter)	❌	7% 🟠

CI / Cross-Version / OpenJDK 26 (ga) > :junit-vintage-engine:test_4_12

Test	Runs	Flakiness
ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter)	❌	7% 🟠

CI / Cross-Version / OpenJDK 26 (leyden) > :junit-vintage-engine:test_4_12

Test	Runs	Flakiness
ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter)	❌	7% 🟠

CI / Cross-Version / OpenJDK 27 (ea) > :junit-vintage-engine:test_4_12

Test	Runs	Flakiness
ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter)	❌	7% 🟠

CI / Cross-Version / OpenJDK 28 (ea) > :junit-vintage-engine:test_4_12

Test	Runs	Flakiness
ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter)	⚠️	7% 🟠

🏷️ Commit: 0c2db3e
▶️ Tests: 941 executed
⚪️ Checks: 17/17 completed

Test Failures (first 10 of 14)

ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter) (:junit-vintage-engine:test\_4\_12 in CI / Build / Windows)

java.lang.AssertionError: 
Expected size: 3 but was: 4 in:
["ForkJoinPool-1-worker-1",
    "ForkJoinPool-1-worker-4",
    "ForkJoinPool-1-worker-2",
    "ForkJoinPool-1-worker-3"]
	at org.junit.vintage.engine.execution.ParallelExecutionIntegrationTests.executesTestClassesAndMethodsInParallel(ParallelExecutionIntegrationTests.java:135)

ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter) (:junit-vintage-engine:test\_4\_12 in CI / Build / Windows)

java.lang.AssertionError: 
Expected size: 3 but was: 4 in:
["ForkJoinPool-5-worker-2",
    "ForkJoinPool-5-worker-3",
    "ForkJoinPool-5-worker-4",
    "ForkJoinPool-5-worker-1"]
	at org.junit.vintage.engine.execution.ParallelExecutionIntegrationTests.executesTestClassesAndMethodsInParallel(ParallelExecutionIntegrationTests.java:135)

ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter) (:junit-vintage-engine:test\_4\_12 in CI / Build / Windows)

java.lang.AssertionError: 
Expected size: 3 but was: 4 in:
["ForkJoinPool-6-worker-2",
    "ForkJoinPool-6-worker-1",
    "ForkJoinPool-6-worker-4",
    "ForkJoinPool-6-worker-3"]
	at org.junit.vintage.engine.execution.ParallelExecutionIntegrationTests.executesTestClassesAndMethodsInParallel(ParallelExecutionIntegrationTests.java:135)

ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter) (:junit-vintage-engine:test\_4\_12 in CI / Cross-Version / OpenJDK 26 (ga))

java.lang.AssertionError: 
Expected size: 3 but was: 4 in:
["ForkJoinPool-1-worker-1",
    "ForkJoinPool-1-worker-4",
    "ForkJoinPool-1-worker-2",
    "ForkJoinPool-1-worker-3"]
	at org.junit.vintage.engine.execution.ParallelExecutionIntegrationTests.executesTestClassesAndMethodsInParallel(ParallelExecutionIntegrationTests.java:135)

ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter) (:junit-vintage-engine:test\_4\_12 in CI / Cross-Version / OpenJDK 26 (ga))

java.lang.AssertionError: 
Expected size: 3 but was: 4 in:
["ForkJoinPool-5-worker-2",
    "ForkJoinPool-5-worker-3",
    "ForkJoinPool-5-worker-4",
    "ForkJoinPool-5-worker-1"]
	at org.junit.vintage.engine.execution.ParallelExecutionIntegrationTests.executesTestClassesAndMethodsInParallel(ParallelExecutionIntegrationTests.java:135)

ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter) (:junit-vintage-engine:test\_4\_12 in CI / Cross-Version / OpenJDK 26 (ga))

java.lang.AssertionError: 
Expected size: 3 but was: 4 in:
["ForkJoinPool-6-worker-2",
    "ForkJoinPool-6-worker-1",
    "ForkJoinPool-6-worker-4",
    "ForkJoinPool-6-worker-3"]
	at org.junit.vintage.engine.execution.ParallelExecutionIntegrationTests.executesTestClassesAndMethodsInParallel(ParallelExecutionIntegrationTests.java:135)

ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter) (:junit-vintage-engine:test\_4\_12 in CI / Cross-Version / OpenJDK 26 (leyden))

java.lang.AssertionError: 
Expected size: 3 but was: 4 in:
["ForkJoinPool-1-worker-1",
    "ForkJoinPool-1-worker-4",
    "ForkJoinPool-1-worker-2",
    "ForkJoinPool-1-worker-3"]
	at org.junit.vintage.engine.execution.ParallelExecutionIntegrationTests.executesTestClassesAndMethodsInParallel(ParallelExecutionIntegrationTests.java:135)

ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter) (:junit-vintage-engine:test\_4\_12 in CI / Cross-Version / OpenJDK 26 (leyden))

java.lang.AssertionError: 
Expected size: 3 but was: 5 in:
["ForkJoinPool-5-worker-2",
    "ForkJoinPool-5-worker-3",
    "ForkJoinPool-5-worker-4",
    "ForkJoinPool-5-worker-5",
    "ForkJoinPool-5-worker-1"]
	at org.junit.vintage.engine.execution.ParallelExecutionIntegrationTests.executesTestClassesAndMethodsInParallel(ParallelExecutionIntegrationTests.java:135)

ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter) (:junit-vintage-engine:test\_4\_12 in CI / Cross-Version / OpenJDK 26 (leyden))

java.lang.AssertionError: 
Expected size: 3 but was: 5 in:
["ForkJoinPool-6-worker-2",
    "ForkJoinPool-6-worker-1",
    "ForkJoinPool-6-worker-4",
    "ForkJoinPool-6-worker-3",
    "ForkJoinPool-6-worker-5"]
	at org.junit.vintage.engine.execution.ParallelExecutionIntegrationTests.executesTestClassesAndMethodsInParallel(ParallelExecutionIntegrationTests.java:135)

ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter) (:junit-vintage-engine:test\_4\_12 in CI / Cross-Version / OpenJDK 27 (ea))

java.lang.AssertionError: 
Expected size: 3 but was: 5 in:
["ForkJoinPool-1-worker-6",
    "ForkJoinPool-1-worker-1",
    "ForkJoinPool-1-worker-4",
    "ForkJoinPool-1-worker-5",
    "ForkJoinPool-1-worker-3"]
	at org.junit.vintage.engine.execution.ParallelExecutionIntegrationTests.executesTestClassesAndMethodsInParallel(ParallelExecutionIntegrationTests.java:135)

Muted Tests

Select tests to mute in this pull request:

ParallelExecutionIntegrationTests > executesTestClassesAndMethodsInParallel(TestReporter)

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danil-pavlov force-pushed the writing-tests-kotlin-part5 branch 2 times, most recently from 044fbcd to e7be7e3 Compare July 22, 2026 11:07

marcphilipp requested changes Jul 25, 2026

View reviewed changes

Comment thread documentation/modules/ROOT/pages/writing-tests/parameterized-classes-and-tests.adoc Outdated

Comment thread documentation/src/test/kotlin/example/kotlin/ParameterizedClassDemo.kt Outdated

danil-pavlov requested a review from marcphilipp July 27, 2026 12:39

marcphilipp requested changes Jul 30, 2026

View reviewed changes

danil-pavlov requested a review from marcphilipp July 30, 2026 15:04

marcphilipp requested changes Jul 31, 2026

View reviewed changes

danil-pavlov requested a review from marcphilipp July 31, 2026 18:18

danil-pavlov force-pushed the writing-tests-kotlin-part5 branch from 1ce793d to f998178 Compare July 31, 2026 18:27

danil-pavlov and others added 7 commits July 31, 2026 20:41

Add Kotlin code examples to last writing tests topics

144793c

Signed-off-by: Danil Pavlov <danil.pavlov@jetbrains.com>

Fix Kotlin includes and examples

a029788

Signed-off-by: Danil Pavlov <danil.pavlov@jetbrains.com>

Fix formatting

15ca983

Signed-off-by: Danil Pavlov <danil.pavlov@jetbrains.com>

Fix inner class output and record example

3dc3554

Signed-off-by: Danil Pavlov <danil.pavlov@jetbrains.com>

Fix Stream and consoleLauncherTest

5f6f6ab

Signed-off-by: Danil Pavlov <danil.pavlov@jetbrains.com>

Fix consoleLauncherTest with PER_CLASS

6aa25af

Signed-off-by: Danil Pavlov <danil.pavlov@jetbrains.com>

Add notes for PER_CLASS

0c2db3e

Signed-off-by: Danil Pavlov <danil.pavlov@jetbrains.com>

danil-pavlov force-pushed the writing-tests-kotlin-part5 branch from f998178 to 0c2db3e Compare July 31, 2026 18:44

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Add Kotlin code examples to last writing tests topics - #5898

Add Kotlin code examples to last writing tests topics#5898
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danil-pavlov commented Jul 22, 2026

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🚨 TestLens detected 4 failed tests 🚨

Test Summary

CI / Build / Windows > :junit-vintage-engine:test_4_12

CI / Cross-Version / OpenJDK 26 (ga) > :junit-vintage-engine:test_4_12

CI / Cross-Version / OpenJDK 26 (leyden) > :junit-vintage-engine:test_4_12

CI / Cross-Version / OpenJDK 27 (ea) > :junit-vintage-engine:test_4_12

CI / Cross-Version / OpenJDK 28 (ea) > :junit-vintage-engine:test_4_12

Test Failures (first 10 of 14)

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