2025-10-02

This release introduces the new dcover issues (Beta) command that helps resolve problems that block test generation, and enhances test quality via an optional LLM integration (Beta) for domain-specific string generation. It also improves test coverage for Java servlets and boosts performance for multi-module Maven projects.

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New dcover issues (Beta) Command & LLM Integration (Beta)

• New dcover issues Command (Beta): Diffblue Cover now provides the new dcover issues command, which analyzes test creation output to consolidate issues and provide context-specific LLM consumable prompts for resolving problems that block test generation. For more details, see our documentation.

• Domain-Specific Test Inputs (Beta): Cover can now use an optional LLM integration (Beta) to generate more domain-specific string inputs for tests. This feature results in higher-quality tests with more semantically appropriate inputs. For more details, see our documentation.

Improved Test Quality & Coverage

• Enhanced Servlet Test Coverage: Cover now generates tests with improved coverage for applications using Java servlets by more effectively analyzing methods that use servlet request and response objects.

Performance & Stability

• Faster Refactoring for Maven Projects: The dcover refactor command now runs more efficiently for multi-module Maven projects by executing a key build step once for the entire project instead of for each module, significantly reducing completion time.

• Custom Build Configuration Support: Resolved an issue that could cause Cover to fail with a project structure error (E016) when using a custom build configuration.

• Gradle Multi-Release JAR Support: An issue has been resolved that caused analysis failures in Gradle projects containing multi-release JAR artifacts, allowing tests to be written successfully.

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Enhancements

• Diffblue Cover now provides the new dcover issues (Beta) command. This command analyzes output from dcover create to consolidate issues and provide context-specific LLM consumable prompts for resolving problems that block test generation. [Ref: TG-23862] Docs

• Diffblue Cover now generates tests with improved coverage for applications using Java servlets by more effectively analyzing methods that use servlet request and response objects. [Ref: TG-23817]

• Diffblue Cover can now generate more domain specific string inputs for tests using its optional LLM integration (Beta). Configuring and enabling this feature allows Cover to write tests with more semantically and domain appropriate test inputs, resulting in better quality tests. Please note that enabling this feature may cause Diffblue Cover to take significantly longer to write tests. [Ref: TG-23770] Docs

• The dcover refactor command now runs more efficiently for multi-module Maven projects. A key build step is now executed once for the entire project instead of for each module, significantly reducing the command's completion time. [Ref: TG-23760]

Resolved Issues

• CLI: Resolved an issue that caused Diffblue Cover to fail with an E016 (Failed to determine project structure) error when using a custom build configuration. [Ref: TG-23882]

• Resolved an issue where Diffblue Cover could select non-optimal string values for method parameters when no other data sources were available. This improves the quality and relevance of the generated unit tests in these specific scenarios. [Ref: TG-23844]

• Resolved an issue that caused analysis failures in Gradle projects containing multi-release JAR artifacts, preventing tests from being written. [Ref: TG-23837]

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]