2026-02-02

This release introduces support for Java 25 projects and enhances the CLI to detect when generated tests fail project style checks, such as Apache Checkstyle.

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Language Support

• Java 25 Support: Diffblue Cover now supports writing tests for Java 25 projects.

CLI & Integration

• Style Check Detection: Cover now detects when generated tests fail a project's style checks (e.g., Apache Checkstyle) during validation. It reports a new E171 warning with guidance on resolving formatting incompatibilities.

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Enhancements

• Diffblue Cover now supports writing tests for projects using Java 25 language features. [Ref: TG-24170]

• CLI: Diffblue Cover now detects when generated tests fail a project's style checks (e.g., Apache Checkstyle) during validation and reports a new E171 warning with guidance on resolving formatting incompatibilities. [Ref: TG-24169]

Known Issues

• Plugin: Diffblue Cover incorrectly displays a menu option to write tests for existing test files. [Ref: TG-17163]

• Using JDKs other than the supported Open JDK and Oracle JDK may produce unexpected results due to implementation differences. [Ref: TG-19345]

• Cover may encounter an F009 (Internal error) caused by a ClassCircularityError involving org/mockito/configuration/MockitoConfiguration when writing tests with Mockito 5. The recommended workaround is to downgrade to Mockito 4.x. [Ref: TG-19610]

• Reports: The total line count metric in Reports only includes Java code. Kotlin code is not included. [Ref: TG-22088]

• Reports: Total lines of code metric can incorrectly count a multi-line comment at the end of a line of code, resulting in fewer than expected lines counted. [Ref: TG-22089]

• Reports: Following an upgrade, the 'Total Lines of Code' card may show 0 until a new reports bundle has been uploaded. [Ref: TG-22094]

• Cover may write more simplistic tests with less meaningful assertions when Spring Boot dependency injection is disabled. [Ref: TG-22102]

• In some circumstances, Cover will still write Spring Boot tests when Spring Boot dependency injection is disabled. [Ref: TG-22103]

• Cover may write failing TestNG tests when Spring Boot dependency injection is disabled. [Ref: TG-22107]

• Plugin: On some displays, the Test Review subsection title 'Tests for review' is malformed. [Ref: TG-22805]

• When test formatting settings are changed, the Test Review feature may incorrectly remove the @ManagedByDiffblue annotation from tests, particularly in cases involving static import formatting changes. [Ref: TG-23750]

• Plugin: Using the Test Review feature may create tests that have incompatible dependency injection systems. [Ref: TG-23935]

• CLI: In rare circumstances, Cover may remove existing tests when using merge mode (--merge). The recommended workaround is to use the @WriteTestsTo annotation to specify a separate test class. [Ref: TG-24166]

• Plugin: When writing tests for a project that targets a JDK version newer than IntelliJ's runtime JDK (e.g., Java 25 with IntelliJ's bundled Java 21), generated tests may not match the project's non-default formatting style and will instead use default IntelliJ formatting. [Ref: TG-24168]