2025-11-01

This release enhances Spring support with performance improvements and more effective controller tests, expands LLM String Generation (Beta) with selective annotation control, and improves CLI command reliability.

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Spring Framework Support

• Performance Improvements: Diffblue Cover now provides significant performance improvements for projects with large Spring entities.

• Enhanced Controller Tests: Cover now generates more effective tests for controller methods that have HttpRequest and HttpSession parameters.

LLM String Generation for Test Inputs (Beta)

• Selective Control: Introduces the @InTestsUseLLM annotation, enabling selective use of LLM-generated string inputs for specific methods, classes, or packages. This allows users to balance test generation speed and API costs by applying realistic string generation only where most needed. Requires cover-annotations library v1.8.0+ and an active LLM Configuration (Beta). For more information, see the LLM Input Annotations documentation.

• Anthropic Models: Resolved an issue that prevented using Anthropic models with the LLM String Generation for Test Inputs beta feature.

CLI Enhancements & Stability

• dcover fix-build Reliability: Resolved an issue where the dcover fix-build command could unreliably update pom.xml files. The command now modifies Maven project configurations with improved reliability.

• dcover validate Command: Resolved an issue where the dcover validate command could remove valid fields, imports, or entire test classes. The command now correctly identifies and removes only individual failing tests.

Test Generation & Quality

• Google Protobuf Support: Resolved a security sandbox policy violation that prevented Cover from writing tests for code using Google Protobuf. Test generation now proceeds successfully in this scenario.

• JUnit Annotation Compatibility: Resolved an issue that could cause Cover to generate tests with incompatible @RunWith and @ExtendWith annotations, ensuring all generated tests have a valid configuration.

IntelliJ Plugin

• Plugin Stability: Resolved a rare issue that could cause an 'Internal Error' after Environment Detection, preventing some users from writing tests. Users in affected environments can now successfully write tests.

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Important Notices

Upcoming End of Support for IntelliJ 2025.1

This release is the final release that supports IntelliJ 2025.1. In line with our policy of supporting the two most recent major versions, support for 2025.1 will be discontinued in an upcoming release.

To continue receiving Diffblue Cover updates and support, users on IntelliJ 2025.1 are advised to upgrade to IntelliJ 2025.2 or newer.

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Enhancements

• Diffblue Cover now generates more effective tests for Spring MVC controller methods that use HttpRequest and HttpSession parameters, improving test coverage for web controllers. [Ref: TG-23940]

• Diffblue Cover now writes tests more quickly for projects containing Spring entities with a large number of fields, resulting in improved overall performance during test generation. [Ref: TG-23839]

• Diffblue Cover now supports the @InTestsUseLLM annotation, enabling selective use of LLM-generated string inputs for specific methods, classes, or packages. This allows users to balance test generation speed and API costs by applying realistic string generation only where most needed. This feature requires cover-annotations library v1.8.0+ and an active LLM Configuration (Beta). [Ref: TG-23811] Docs

Resolved Issues

• Resolved an issue where a security sandbox policy violation would prevent Diffblue Cover from writing tests for code using Google Protobuf. Test generation will now proceed for methods that previously triggered an R011 output code in this scenario. [Ref: TG-23902]

• Resolved an issue which prevented the use of Anthropic / Claude models for the LLM String Generation for Test Inputs beta feature. Diffblue Cover can now correctly connect to this provider to generate realistic string values in tests. [Ref: TG-23892]

• Plugin: Resolved a rare issue that caused an 'Internal Error' after Environment Detection due to a class path resolution problem, which prevented some users from writing tests. [Ref: TG-23890]

• CLI: Resolved an issue that caused the dcover fix-build command to unreliably update pom.xml files. The command now reliably modifies Maven project configurations to resolve testability blockers. [Ref: TG-23392]

• Resolved an issue that could cause Diffblue Cover to generate tests with incompatible @RunWith and @ExtendWith annotations. All generated tests now have compatible annotation configurations. [Ref: TG-23378]

• Resolved an issue where the dcover validate command could incorrectly remove valid fields, imports, or entire test classes. The command now correctly identifies and removes only individual failing tests. [Ref: TG-23151]

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]