What's New > Version 2021.04.02

Extended Mockito support

Release date: Apr 26, 2021

Extended Mockito support

Diffblue Cover now supports Mockito versions 2.1 through 3.9.

Enhanced mocking

Diffblue Cover now uses mocking to provide method parameters when functional interfaces need to be passed in.

Queuing tests - Diffblue Cover IntelliJ Plugin

Diffblue Cover IntelliJ Plugin now allows writing tests to be queued whilst indexing is completing.

Diffblue Cover Community Edition is now available for use with commercial code

We’ve updated our End-User License Agreement to open up Community Edition for writing tests for both open source and commercial code. This means you can now use Diffblue Cover Community Edition at work completely for free.

Many organisations may have restrictions against using free software or need additional protection. Visit our documentation to learn more about how you can use Diffblue Cover at work.


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 supports Mockito versions 2.1 through 3.9. [Ref: TG-14210]

  • Cover now uses mocks to provide method parameters when functional interfaces such as Predicate, Consumer or Supplier need to be passed in. [Ref: TG-13833]

  • Cover now logs the classpath that was in use and where possible, the failure cause, when an ‘Unable to load class’ error (R005) occurs. [Ref: TG-13551, TG-14226]

  • CLI: Cover now provides additional console output to show the path to Maven it is using and the command used to execute it. [Ref: TG-14068]

  • IntelliJ Plugin: Cover now allows invocations of ‘Write Tests’ to be queued for execution if indexing is incomplete. [Ref: TG-13959]

Resolved Issues

  • CLI: Resolved an issue which would cause Cover to fail if the mockito-inline dependency was included on the classpath. [Ref: TG-14057]

  • IntelliJ Plugin: Resolved an issue where clicking ‘Write Tests’, after cancelling indexing, may provoke a Couldn't find index for module error. [Ref: TG-13555]

Known Issues

  • CLI: Windows: creating config.json by outputting --example-config as file causes exceptions. [Ref: TG-11198]

  • CLI: All tests may be discarded in test validation when using --config. [Ref: TG-11475]

  • CLI: dcover clean --working-directory throws an error if --test-output-dir is not provided. [Ref: TG-11665]

  • CLI: Cover fails to generate tests, reporting java.lang.OutOfMemoryError, when analyzing projects which spawn a quantity of threads in excess of the operating system’s process thread limit. [Ref: TG-11680]

  • 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]