What's New > Version 2021.09.01

Improved Test Writing

Release date: Sep 14, 2021

Improved test writing from Diffblue Cover

This release, Diffblue Cover has improved test writing in the following ways:

  • Automatically creating mocked instances of ‘bean-like’ interfaces
  • Using more appropriate timezone values when mocking method results
  • Using additional constant values as inputs for tests.

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 uses more appropriate timezone values when mocking method results. [Ref: TG-15333]

  • Cover no longer writes JUnit 5 tests with the ‘public access modifier’, which some code quality analysis tools flag as a ‘code smell’. [Ref: TG-15331]

  • Cover is now able to use additional constant values, provided via a file, to be used as additional inputs for tests. [Ref: TG-15329]

  • Cover is now able to automatically create mocked instances of ‘bean-like’ interfaces. [Ref: TG-15173]

Resolved Issues

  • CLI: Resolved an issue where dcover clean failed to automatically detect the classpath. [Ref: TG-15402]

  • IntelliJ Plugin: Resolved an issue which caused the “Allow collection of anonymized usage statistics” checkbox to be shown in the wrong location. [Ref: TG-15224]

  • Resolved an issue which caused Validation command failed for unknown reason to be logged on Unix systems, using Surefire, with spaces in the path name. [Ref: TG-15080]

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]