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Open Test Alliance for the JVM


This project is the result of an initiative by the JUnit 5 team.

Status Quo

There is no standard for testing on the JVM: the only common building block we have is java.lang.AssertionError.

AssertionError is great for signaling that a test has failed, but it doesn't go far enough. Each testing framework is therefore forced to fill the gap with custom subclasses of AssertionError or RuntimeException to provide a richer feature set to end users. The downside is that each framework has its own set of custom errors and exceptions, and this makes it a challenge for frameworks to interoperate.

For example, JUnit has long supported the notion of a failed assumption via its AssumptionViolatedException, but assertion frameworks like AssertJ cannot integrate that feature without a direct dependency on JUnit. Furthermore, the status quo makes the work of IDEs and build tools more difficult than it should be.


The only real solution to this problem is to create a foundation that we can all build on!

Based on discussions with IDE and build tool developers from Eclipse, Gradle, and IntelliJ, the JUnit 5 team is working on a proposal for an open source project to provide a minimal common foundation for testing libraries on the JVM. The primary goal of the project is to enable testing frameworks like JUnit, TestNG, Spock, etc. and third-party assertion libraries like Hamcrest, AssertJ, etc. to use a common set of exceptions that IDEs and build tools can support in a consistent manner across all testing scenarios -- for example, for consistent handling of failed assertions and failed assumptions as well as visualization of test execution in IDEs and reports.

Initial Implementation

We have begun with a small set of errors and exceptions that we consider to be common for all testing and assertion frameworks. In fact, these errors and exceptions are already used in JUnit 5. Please take a look at the project and let us know what you think.



Contributions to the Open Test Alliance are both welcomed and appreciated. For specific guidelines regarding contributions, please see in the root directory of the project. Those willing to use milestone or SNAPSHOT releases are encouraged to file feature requests and bug reports using the project's issue tracker.

Feedback is welcome!

What types of errors and exceptions should the OTA support?

What types of properties should such errors and exceptions have?

What additional functionality (e.g., interfaces, utility methods, etc.) should the OTA provide?

Projects already contacted

We've already reached out to and asked for feedback from the maintainers of the following projects.

  • Test NG
  • Hamcrest
  • AssertJ
  • Spock
  • Google Truth
  • ScalaTest
  • Eclipse
  • IntelliJ
  • Gradle
  • Maven Surefire Plugin
  • Allure Framework


Release artifacts are deployed to Maven Central.

Snapshot artifacts are deployed to Sonatype's snapshots repository.

Dependency Metadata

Latest Release

  • Group ID: org.opentest4j
  • Artifact ID: opentest4j
  • Version: 1.2.0

See also:|ga|1|opentest4j/


  • Group ID: org.opentest4j
  • Artifact ID: opentest4j
  • Version: 1.3.0-SNAPSHOT

See also: