What's New > Version 2021.07.02

Getting the best user experience with Diffblue Cover

Release date: Jul 19, 2021

Getting the best user experience with Diffblue Cover

We have updated our user messaging to help you have the best test creation experience with Diffblue Cover. In this release, we have made the following enhancements:

  • Updated our messaging to help you create more tests.
  • Improved the readability of multi-line logging messages.
  • Repeated important WARN messages in a summary section to ensure they are not missed.
  • Added guidance on using the best combination of test dependencies to ensure Diffblue Cover can create the best tests.
  • Added in checks to determine whether the project has been compiled correctly.

Diffblue Cover Community Edition is available for use with commercial code

Community Edition allows you to write tests for both open source and commercial code. This means you can now use Diffblue Cover Community Edition at work completely for free. Visit our documentation to learn more about how you can use Diffblue Cover at work, and also see our End-User License Agreement.


If you have feedback, questions or requests regarding the Diffblue Cover IntelliJ Plugin, please contact us on the Community Forum. We would love to hear about what is important to you and what you would like to see in upcoming releases.

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.

Full Release Notes


  • Cover now provides improved reporting and further guidance for R013 and R015 output codes. [Ref: TG-14942]

  • Cover now writes tests which assert on LocalDate, LocalTime and LocalDateTime. [Ref: TG-13997]

  • CLI: Cover now exits with a clear error, and further guidance, if dcover create has been executed in a project which has not yet been compiled. [Ref: TG-13982]

  • CLI: Cover now provides warnings if minimum supported versions of Spring dependencies are missing from the classpath. [Ref: TG-14930]

  • CLI: Cover now provides improved console output, particularly for multi-line messages. [Ref: TG-14847]

  • CLI: Cover now provides a summary of any WARN messages logged during test creation, at the end of the console output. [Ref: TG-14773]

Resolved Issues

  • IntelliJ Plugin: Resolved an issue which, on recent IntelliJ IDEA releases, may provoke an error containing Cannot run program <path to java> Malformed argument has embedded quote: [...]. [Ref: TG-15075]

  • IntelliJ Plugin: Resolved an issue which, in some circumstances, provoked an IntelliJ IDEA RuntimeException: Document is locked by write PSI operations error report. [Ref: TG-14925]

  • IntelliJ Plugin: Resolved an issue which, in some circumstances, provoked an IntelliJ IDEA java.lang.UnsupportedOperationException: null error report. [Ref: TG-14634]

  • IntelliJ Plugin: Resolved an issue which, in some circumstances, provoked an IntelliJ IDEA IllegalArgumentException: Bad escape error report. [Ref: TG-13525]

Known Issues

  • CLI: dcover clean --failing fails when used with a Gradle project. [Ref: TG-11707]

  • IntelliJ Plugin: Diffblue Cover was unable to create an index error may appear if switching project happens before Cover has finished indexing. [Ref: TG-13772]