Diffblue Cover is an AI agent for automating the generation, maintenance and management of Java unit tests.
Unlike LLM-based coding assistants that help write individual tests when prompted, Diffblue Cover uses reinforcement learning (RL) to autonomously produce comprehensive coverage across entire codebases, perfect for meeting coverage gates, catching regressions, and shipping with confidence.
Proven at Enterprise Scale:
* US Aerospace and Defense company: 1M lines of code coverage initiative
* Goldman Sachs: From 36% to 72% in less than 10% of the time it would take to do it manually
* US Pension & Retirement System: 70% unit coverage without manual effort
* Handles what others can't: Complex Spring contexts, Guice, legacy singletons, millions of lines of codeLOC without OOM errors, tests are guaranteed to compile and pass
Diffblue Cover augments developers by automating away tedious and time-consuming aspects of the Java unit test generation process.
Documents actual behavior:
Unit tests reveal what your code really does (not what comments claim), essential for understanding legacy systems and inherited codebases.
Enables rapid coverage increases:
Creates unit tests in bulk, covering all relevant branches to rapidly improve coverage and enable teams to reach and maintain coverage goals.
Handles enterprise complexity:
Works with complex Spring contexts, Mockito configurations, and legacy patterns that cause other tools to fail with OOM errors.
Enables safe refactoring:
Create regression safety net before Java version upgrades, cloud migrations, or modernization initiatives. Know what breaks before production.
Secures inherited codebases:
Generate comprehensive test suites for acquired or legacy code with 0% coverage, creating a safety net for integration and modification.
Unblocks CI/CD pipelines:
Rapidly increase coverage to meet gates blocking your deployments, achieving in days what would take months manually.
Use Cases:
Accelerate Development:
✓ Sprint velocity improvement - Stop spending 30-50% of time writing tests
✓ New feature protection - Ensure all new code has regression tests
✓ Refactoring confidence - Safe changes with comprehensive test coverage
✓ Code review acceleration - PRs include tests automatically
Meet Requirements:
✓ Coverage gates and requirements - Achieve targets faster than manual writing
✓ Compliance mandates - SOC2/ISO/MRM requiring test evidence
✓ Quality initiatives - Systematic improvement of test coverage
✓ Technical debt reduction - Address testing gaps efficiently
Enable Transformation:
✓ Java version upgrades - Test safety net for 8→11/17/21 migrations
✓ Architecture modernization - Confidence to refactor and improve
✓ Cloud migration - Ensure functionality during platform changes
✓ M&A integration - Quickly understand and test acquired code
