Diffblue Cover is an automated unit test-writing tool. It analyses your existing Java application and writes unit tests that reflect the current behavior, increasing test coverage and helping you find regressions in future code changes. Cover automatically maintains the tests by updating them when your code changes. Cover supports Java 8, 11, 17 and 21, Spring and Spring Boot. Cover is available as a CLI tool for Windows, Linux and macOS, and works 100% autonomously, configuring itself from your Maven or Gradle environment. There is also a Cover plug-in for IntelliJ IDEA for interactive test writing.