Results of ongoing efforts to speed up test writing with our IntelliJ


We are delighted to report the results of our ongoing efforts to accelerate the writing of tests. Thanks to incremental improvements over the last few releases, Cover today completes the 'write tests' stage 50% faster (on average against our internal benchmarks). Allowing our customers to write tests even faster.

Removal of on-disk index writing

In our constant quest for speed, we have optimized away the need for producing an on-disk index when writing tests. This results in a further time saving on test writing equivalent to 1 second per module.

Streamlined console output

Harnessing the enhanced log file functionality released previously (in 2022.09.01) we have taken the opportunity to reduce the amount of non-actionable information reported in the CLI console and tool panel. This results in clearer, more targeted output allowing users to produce tests even more efficiently.

Full information continues to be written to the support log files should detailed analysis be required.

Full what's new information available from within the IntelliJ plug-in

Convenient access to the full 'What's New' and release notes has been added to the IntelliJ plug-in menu, allowing you to keep informed of new features and enhancements as we continue to add them.

Meet the Diffblue team at Devoxx in October

Diffblue are delighted to be sponsoring Devoxx Belgium 2022.{: target="_blank" rel="noopener"} Our team can't wait to talk about AI for Code with the Java development community.

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.


  • Cover now writes tests for Spring Controller methods with @RequestBody Map<> arguments. [Ref: TG-17068]

  • CLI: Cover's deprecated dcover clean --failing subcommand has been removed and dcover validate should be used instead. [Ref: TG-17790]

  • CLI: Cover now provides a 'duration' at the end of execution. Timestamp prefixes have been removed from console output. [Ref: TG-17714]

  • IntelliJ Plugin: Cover now shows 'what's new' updates in an IDE tab rather than a window overlay. [Ref: TG-17653]

Resolved Issues

  • Resolved an issue which, in some circumstances, caused Cover to report R013 while writing tests for methods which inherit annotations. [Ref: TG-17686]

  • Resolved an issue which prevented Cover creating Map implementation inputs that meet constraints outside of the class under test. [Ref: TG-17212]

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