New Diffblue Cover features

Four new features - Reports, Optimize, Refactor and Replay - have been added in this release of Diffblue Cover. In addition to autonomously writing and maintaining entire unit test suites without developer intervention, Cover Enterprise Edition now enables you to:

  • Automatically refactor Java code to improve testability

  • Slash the time and cost to run tests in Continuous Integration

  • Understand test coverage and code risk across your organization

  • Automatically shift complex functional tests left into unit test suites

Read this blog post or watch this short YouTube playlist to learn more about the new features. Then if you're interested in how the power of Enterprise Edition could help your team, get in touch via our website.

Developer Edition trial available

We are delighted to now offer a 14-day trial version of our Developer Edition, which includes the Diffblue Cover CLI, as part of our new licensing option. We're really excited that you can now "try before you buy"! To download your trial of Diffblue Cover Developer Edition, please click here. Full information on all our options is also available here.

How do I automatically maintain all of these tests?

Use Diffblue Cover on any CI platform to automatically update your unit tests and catch regressions for every commit - watch this video to learn more.


  • IntelliJ Plugin: Cover now asks for a test framework to be selected, via the plugin settings, when multiple test frameworks are on the classpath, rather than defaulting to JUnit 5. [Ref: TG-18006]

  • Cover now supports customizing test inputs via DiffblueRules.yaml in addition to the previously supported DiffblueRules.yml, with the former taking precedence. Problems with custom inputs are treated as an error and Cover will not attempt to create tests with invalid custom input rules. See the customizing test inputs documentation for more details.

Resolved Issues

  • Resolved an issue which, in some circumstances, caused Cover to report F009 instead of writing tests because of a field inheriting from a class with generic parameters. [Ref: TG-18097]

  • Resolved an issue which caused Cover to attempt to mock non-accessible, package-private, classes whilst writing tests from outside of their package. [Ref: TG-18070]

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