run-java-test

name	run-java-test
description	Use when: running a Java test class or suite (including JUnit 4 WildcardPatternSuite like `AllTests`) through the VS Code Java Test Runner from an agent. Keywords: run Java test, JUnit, AllTests, vscode test runner, java.test.editor.run, test file not found, No tests found in the files.

Run a Java Test via the VS Code Test Runner

This skill documents the only reliable way to run a Java test class in this workspace from an automated agent, without invoking Maven.

When to use

• The user asks to run a specific Java test class or the AllTests suite.
• The generic VS Code test runner tool returns No tests found in the files when given a Java test file path.

Permission

• You do NOT need to ask for permission to run the test file you are currently fixing or editing. Running these tests via the Java Test Runner (java.test.editor.run) is a safe, read-only verification step — just run it.
• The mvn/build human-consent rule still applies: never fall back to mvn test to run tests without explicit human consent.

Why the generic runner is insufficient

The generic VS Code test runner tool (runTests) does not discover Java tests in this workspace, even when given the absolute path of a *Test.java file or the path of a JUnit 4 WildcardPatternSuite class such as owlcms/src/test/java/app/owlcms/tests/AllTests.java. It returns No tests found in the files.

The Java Test Runner extension exposes java.test.editor.run, which runs the tests defined in the currently active editor. That command works for both plain JUnit classes and the AllTests wildcard suite.

Required steps

1. Open the target test file in the active VS Code window using the code CLI so it becomes the active editor:

   code -r /absolute/path/to/SomeTest.java
   

   Use -r (reuse window). Do not use the vscode.open command via run_vscode_command — it fails in the agent tool context.

2. Run the Java Test Runner command on the current file:

   • command: java.test.editor.run
   • name: Java: Run Tests in Current File

3. Read the returned JSON payload. Failures appear as items with ownComputedState == 4. The payload is usually large and gets written to a chat-session-resources/.../content.txt file — parse it with jq:

   tail -n +3 "$out" | jq -r '.items[]
     | select(.ownComputedState == 4)
     | .item.label'
   

4. The Java Test Runner does not include stack traces in the returned payload, and the underlying test task output is not retrievable by task id afterward. Report which test methods failed and inspect the source to diagnose. Do not fall back to Maven without explicit human consent.

State code reference (Java Test Runner payload)

ownComputedState	Meaning
0	Unset
1	Queued
2	Running
3	Passed
4	Failed
5	Skipped
6	Errored

Do not

• Do not call runTests directly on a Java test file path — it returns No tests found in the files.
• Do not run mvn test to work around this — Maven requires explicit human consent in this repository.
• Do not try to call java.test.runTests directly — it expects internal VS Code TestRunRequest objects that cannot be constructed from the agent.