What's New > Version 2021.08.02

Getting more tests with Diffblue Cover

Release date: Aug 16, 2021

Getting more tests with Diffblue Cover

Test writing has been enhanced in this release with the following:

  • The use of more realistic numbers as inputs when testing mathematical code, i.e. avoiding the use of the number 1, using a mix of positive and negative numbers, and using decimal numbers when parameters are of type double, Double, float, Float.
  • Automatically adding any missing beans at context creation, meaning that Diffblue Cover is more robust when creating unit tests.

Additional Maven versions now supported

Cover now supports all versions of Maven from version 3.2.5 onwards.

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 writes tests which verify if a mocked method is called multiple times using Mockito‚Äôs atLeast(n) rather than times(n), making tests more deterministic. [Ref: TG-15148]

  • Cover now writes tests which use a wider variety of input values for mathematical code. [Ref: TG-15055]

  • Cover now writes improved tests for methods which catch Exception. [Ref: TG-15036]

  • Cover now supports earlier versions of Maven. Cover requires Maven 3.2.5 or higher. [Ref: TG-15167]

  • Cover now provides more helpful feedback if it fails to start the analyzer service. [Ref: TG-14998]

  • Cover is now more robust when creating contexts for Spring unit tests. [Ref: TG-15217]

Resolved Issues

  • Resolved an issue which prevented Cover from providing an error, and further guidance, when only a JRE is available. [Ref: TG-14725]

  • IntelliJ Plugin: Resolved an issue which, in some circumstances, provoked an IntelliJ Throwable: Slow operations are prohibited on EDT error report. [Ref: TG-15221]

  • IntelliJ Plugin: Resolved an issue which caused HTML output to be shown when R013 output codes were encountered. [Ref: TG-15198]

  • CLI: Resolved an issue which caused the progress bar, shown during test creation, to become inaccurate. [Ref: TG-15233]

  • CLI: Resolved an issue which, in some circumstances, caused the downloading of required JUnit dependencies for Gradle projects to fail. [Ref: TG-15195]

  • CLI: Resolved an issue which resulted in the JAVA_HOME not found in your environment. message not being logged if Cover was unable to find a java executable. [Ref: TG-15107]

  • CLI: Resolved an issue which, in some circumstances, caused class names to be incorrectly formatted when an R005 output code was encountered. [Ref: TG-14804]

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]