Diffblue Cover - AI Agent for Java unit test generation and management - Diffblue
The hard truths about generating Java unit test coverage for application modernization
Modernization depends on coverage
Thorough unit test coverage is the foundation of safe refactoring and application modernization, yet many large Java codebases lack sufficient coverage to move quickly and confidently.
Automation must scale, not assist
Generating thousands of unit tests fast enough requires automation, but generic LLM coding assistants rely on continuous prompting and manual review, which makes them hard to scale across evolving systems.
Coverage alone isn’t enough
High coverage doesn’t automatically mean safety. If unit tests don’t reflect real behavior—or aren’t maintained as the code evolves—they become noise: flaky pipelines, brittle refactors, and false confidence during modernization.
The Solution: Diffblue Cover
Built for autonomous Java unit testing
Diffblue’s unit test generation agent is designed specifically for this challenge, autonomously producing high-quality Java unit tests that deliver meaningful coverage with minimal ongoing developer effort.
LLM-based coding assistants can do impressive things, but they’re not built to deliver comprehensive unit testing coverage. They don’t reason about full applications, struggle with consistency, and can’t guarantee regression safety across a changing codebase.
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Why generic LLM coding assistants aren’t enough
How Diffblue Cover automates Java unit test coverage end-to-end
Analyze your code, generate meaningful JUnit tests, keep them in sync as the code changes, and track coverage and risk in Cover Reports.
Analyze: Understand your Java application
Cover models classes, methods, and behavior across your codebase to target meaningful test generation.
Generate: Generate meaningful tests
Produces human-readable JUnit tests using program analysis, generated in the IDE, via CLI, or automatically in CI.
Maintain: Keep tests in sync
Updates, adds, or removes tests as behavior changes, keeping regression coverage stable as the code evolves.
Assess: Monitor coverage, risk, and testability
Visualize coverage, coverage risk, and testability in Cover Reports, so teams can prioritize improvements and track progress.
Driving big results for enterprise organizations worldwide
59M +
lines of Java tested
1,000 years
of developer time saved
Up to 250x
faster test creation vs humans
Built for the way Java teams work
Run automated Java unit testing in the IDE for fast iteration, via CLI for scale, and in CI/CD to keep tests current on every merge.
Integrates with your Java toolchain
