Kotest

A guide for generating Trunk-compatible test reports for Kotest

You can automatically detect and manage flaky tests in your Kotest projects by integrating with Trunk. This document explains how to configure Kotest to output JUnit XML reports that can be uploaded to Trunk for analysis.

Checklist

By the end of this guide, you should achieve the following before proceeding to the next steps to configure your CI provider.

Generate a compatible test report
Configure the report file path or glob
Disable retries for better detection accuracy
Test uploads locally

After correctly generating reports following the above steps, you'll be ready to move on to the next steps to configure uploads in CI.

Generating Reports

Steps for generating JUnit XML reports for Kotest depend on the build system you use for your project:

Tests run with Gradle will generate Trunk-compatible JUnit XML reports by default. You can further configure reporting behavior in your build.gradle.kts or build.gradle.

Kotest projects using Maven require the following to be added to a project's pom.xml so JUnit XML reports can be generated:

the maven-surefire-plugin must be added to the plugins section of pom.xml

pom.xml

<project>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>3.2.2</version>
            </plugin>
            
            <!-- other plugins -->
        </plugins>
    </build>
</project>

the kotest-extensions-junitxml must be added to the dependencies section of pom.xml

pom.xml

<dependencies>
    <dependency>
        <groupId>io.kotest</groupId>
        <artifactId>kotest-extensions-junitxml-jvm</artifactId>
        <version>5.9.0</version>
        <scope>test</scope>
    </dependency>
    
    <!-- other dependencies -->
</dependencies>

Report File Path

You can configure the path for generated JUnit XML files:

By default, Kotlin projects will produce a directory with JUnit XML reports under ./app/build/test-results/test. You can locate these files with the glob "./app/build/test-results/test/*.xml".

If you wish to override the default test result path, you can do so in the build.gradle.kts or build.gradle files:

build.gradle.kts (Kotlin) or build.gradle (Groovy)

java.testResultsDir = layout.buildDirectory.dir("junit-reports")

You can change the report file path by configuring the reportsDirectory in your maven-surefire-plugin in your pom.xml file:

pom.xml

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>3.2.2</version>
    <configuration>
        <reportsDirectory>${project.build.directory}/junit/</reportsDirectory>
    </configuration>
</plugin>

The example above will output JUnit XML reports that can be located with the /target/junit/*.xml glob.

Disable Retries

You need to disable automatic retries if you previously enabled them. Retries compromise the accurate detection of flaky tests. You should disable retries for accurate detection and use the Quarantining feature to stop flaky tests from failing your CI jobs.

If you've enabled retries using a plugin like the test-retry-gradle-plugin, disable it when running tests for Trunk flaky tests.

Maven uses the maven-surefire-plugin to run tests, which allows you to control the test retry behavior. You can disable retries by specifying 0 retries:

mvn -Dsurefire.rerunFailingTestsCount=0 test

Try It Locally

The Validate Command

You can validate your test reports using the Trunk CLI. If you don't have it installed already, you can install and run the validate command like this:

curl -fsSLO --retry 3 https://trunk.io/releases/trunk && chmod +x trunk
./trunk flakytests validate --junit-paths "./app/junit-reports/*.xml"

Make sure to specify the path to your JUnit XML test reports.

This will not upload anything to Trunk. To improve detection accuracy, you should address all errors and warnings before proceeding to the next steps.

Test Upload

Before modifying your CI jobs to automatically upload test results to Trunk, try uploading a single test run manually.

You make an upload to Trunk using the following command:

curl -fsSLO --retry 3 https://trunk.io/releases/trunk && chmod +x trunk
./trunk flakytests upload --junit-paths "./app/junit-reports/*.xml" \
    --org-url-slug <TRUNK_ORG_SLUG> \
    --token <TRUNK_ORG_TOKEN>

You can find your Trunk organization slug and token in the settings or by following these instructions. After your upload, you can verify that Trunk has received and processed it successfully in the Uploads tab. Warnings will be displayed if the report has issues.