This release provides enhancements that can increase the number of tests written via the CLI. Test writing has been improved for projects using Quarkus. Support for projects using Gradle 8.6.x and 8.7.x has been added. Additionally, the Cover CLI and Plugin have received usability, performance, and test writing bug fixes, detailed in the full release notes.


  • Cover now issues a warning when libraries with limited support are identified on the classpath. [Ref: TG-21311]

  • Cover now supports Gradle 8.6.x and 8.7.x. [Ref: TG-21307]

  • Plugin: Cover now provides a sidebar action to restart test creation via the Diffblue Tool Panel. [Ref: TG-21249]

  • Plugin: Improved test writing performance. [Ref: TG-21237]

  • Cover now detects the Quarkus framework and attempts to write tests for code which uses it. [Ref: TG-21171]

  • Cover now writes tests which use inputs from the static final fields found in code under test. [Ref: TG-20643]

  • Cover now, in some circumstances, produces more tests by removing only the failing tests during validation, rather than removing the entire test class. [Ref: TG-19071]

Resolved Issues

  • Resolved an issue which caused Cover to not write tests if spring-web-test and spring-boot were on the classpath but spring-boot-test was not. [Ref: TG-21215]

  • CLI & Reports: Resolved an issue which caused Cover to produce reports with zero coverage because the --class-name-template option was not available with the coverage-reports command. [Ref: TG-21214]

  • Plugin: Resolved an issue which, in some circumstances, caused the IntelliJ IDE to freeze for a short period of time after clicking 'Write Tests'. [Ref: TG-20949]

  • CLI: Resolved an issue which, when calling dcover create --help, caused Cover to display a usage message for dcover, rather than dcover create [Ref: TG-20543]

Known Issues

  • Plugin: After adding a dependency with 'Fix Issues' at the package level, using 'Restart' in the Diffblue tool panel can cause it to hang on the 'Preparing' phase. Use run configurations to restart test creation for the package. [Ref: TG-21382]

  • Plugin: Cover incorrectly provides a menu option to write tests for a test file. [Ref: TG-17163]

  • CLI & Plugin: Cover may write tests for JUnit 4.10 and lower that do not compile due to the use of assertNotEquals. [Ref: TG-17605]

  • Cover supports Open JDK and Oracle JDK; results with other JDKs may differ due to the variability in their implementations of Java. [Ref: TG-19345]

  • Cover may encounter an F009: Internal error while writing tests using Mockito 5. To avoid this issue use a version of Mockito earlier than 5. [Ref: TG-19610]

  • Under some circumstances, when writing Java tests for Kotlin code, Cover may produce non-compiling tests. [Ref: TG-20759]

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