The things we get asked the most. Always worth a look.

What is Diffblue Cover?

Diffblue Cover is a reinforcement learning AI platform that automatically writes comprehensive, human-like Java unit tests. Cover is provided as an IDE plugin (Cover Plugin) and a CLI application (Cover CLI) for developer use and can also be integrated into your CI Pipeline (Cover Pipeline). We've also added three reporting and optimization tools for further monitoring and management control (Cover Reports, Cover Optimize, and Cover Refactor).

See What is Diffblue Cover? for more details and to view our intro video.

Do I have to upload my code to a cloud service?

No. Cover Plugin and Cover CLI are used on developer workstations and Cover Pipeline operates within your CI environment.

What are the benefits of using Diffblue Cover?

Diffblue Cover helps your team increase automation of your CI pipeline.

For development teams, this:

  • Improves velocity and quality of the software you deliver.

  • Frees up time to focus on creating new features.

For DevOps teams, this:

  • Helps catch errors and issues earlier (shift left!).

  • Improves deployment frequency, lead time, and mean time to repair (MTTR).

See Diffblue Cover #in-summary for more details.

Will the tests find regressions in my code?

Yes. Diffblue Cover quickly generates tests that will allow you to adopt CI. The generated tests will help developers quickly identify regressions in subsequent commits before committing new versions.

What are the requirements for running Diffblue Cover?

Basic pre-requisites:

  • Java 8, 11, 17, or 21 compatible source code, or Kotlin source code.

  • Maven 3.2.5+ or Gradle 4.9+ build tools.

  • The project (for use with Diffblue Cover) must compile and run with no failing unit tests. JUnit and TestNG testing frameworks are supported.

More details:

Diffblue Cover requires that the system environment (hardware, operating system, network connectivity, Java installation) as well as the project environment (build tooling, dependencies, presence of artifacts, existing unit tests) meet the minimum requirements as detailed in Specs & Reqs. Diffblue Cover will perform an environment check before analysis begins to ensure that the requirements are met - if there are any issues, these will be reported using Output Codes.

Note that you can run dcover create --preflight (using Diffblue Cover CLI) to check the Cover pre-requisites for your project, without performing any other actions.

How can I learn more about customers using Diffblue Cover?

See our case study on how Goldman Sachs has benefited from using Diffblue Cover to increase coverage and create a safety net against regressions.

For examples of other ways our customers use Diffblue Cover, click here.

How do we maintain Diffblue unit tests in the future?

Diffblue regression suites are maintained automatically and updated with each new code version to capture the current behavior of the code.

How does Diffblue Cover help me adopt Continuous Integration?

Diffblue Cover AI analyzes your code and writes Java unit tests that run in a CI pipeline after each commit. Cover’s tests:

  • Always compile.

  • Run quickly.

  • Detect regressions from previous versions.

  • Improve coverage.

  • Are easy to understand.

Should our team stop writing unit tests after adopting Diffblue Cover?

No. Diffblue Cover is meant to complement your own unit tests and help you catch regressions.

How is a unit test different from a Diffblue regression suite?

Developers write individual unit tests to test specific functionality. Diffblue regression suites are generated automatically to help find regressions early in the development cycle. Find out more in our Unit Regression Tests eBook.

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