Get started - Cover Refactor

Get started with Diffblue Cover Refactor - no download or install needed, it's integrated directly into Cover CLI and Cover Pipeline.

Diffblue Cover Refactor makes your code more testable - it suggests refactoring patches for your code that allow Diffblue Cover to create more and better tests for your project, and these suggestions can then be automatically applied to your code.

Note that this getting started topic focuses on Cover CLI - for information on using Cover Refactor with Cover Pipeline see Cover Pipeline.

Prefer video? No problem. Check out our getting started video.

Using Cover Refactor

Diffblue Cover generates Output Codes when running dcover create. Each of these output codes identifies a potential issue with your environment or your code base, which could potentially be fixed automatically. Performing these fixes is the purpose of Diffblue Cover Refactor.

1. When running dcover create on a module, a refactorings.yml file is stored in the .diffblue directory of the module. This file contains a description of the refactorings that Diffblue Cover Refactor can perform on your code base.

2. Running dcover refactor applies these refactorings to your code base. You can view the code changes performed by Diffblue Cover Refactor using git diff or similar, and then commit them to your code base when you're happy.

3. If you run dcover create again after recompiling your project, Diffblue Cover will take the refactorings into account, potentially producing more and better tests for your code base.

Note: Steps 1 and 2 can be performed jointly using dcover create --refactor

Considerations and limitations

• OpenRewrite Maven or Gradle plugin (and its transitive dependencies) must be available in your local Maven or Gradle mirror.

  • OpenRewrite Gradle plugin: 6.12.0

  • OpenRewrite Maven plugin: 5.28.0

• For Gradle projects, only the Groovy DSL is supported at this time.
• Cover Refactor only supports refactoring of the following. Future releases will expand this output code set.

  • Missing observers

    • R002 - Missing observers
  • Missing dependencies

    • E027 - JUnit Jupiter Engine not found
    • E052 - Missing dependency
    • E086 - Specified test framework not available
    • E118 - JUnit Vintage Engine not found
    • E137 - Mockito JUnit Jupiter is not configured
  • Incompatible dependency versions

    • E013 - Compatible launcher not found
    • E053 - Unsupported dependency
    • E066 - Dependency incompatible with JDK
    • E119 - JUnit Vintage Engine incompatible