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. Diffblue Cover automatically maintains the tests by updating them when your code changes. It supports standard Java 8 and 11, Spring and Spring Boot.
Diffblue Cover is available as Diffblue Cover CLI and the Diffblue Cover plugin for IntelliJ. (The plugin is available in two versions - Community Edition and Professional Edition).

Below is a feature comparison:

Operating Systems

CLI IntelliJ Plugin
Windows 10 Enterprise
Ubuntu 18.04
RHEL 7.7
macOS 10.15

Hardware Requirements

CLI IntelliJ Plugin
Minimum RAM
16 GB 16 GB
Minimum disk space
5 GB 5 GB
4 4
TCP connection
Cover requires the use of an analysis service that communicates with the plugin and CLI via TCP connections on localhost. In particular, Cover must be able to start up the analysis service, and open a TCP connection from the frontend to the service, and from the service to the frontend.

IntelliJ Versions

CLI IntelliJ Plugin
IntelliJ Community 2021.2
IntelliJ Community 2021.1
IntelliJ Ultimate 2021.2
IntelliJ Ultimate 2021.1

Java Versions

CLI IntelliJ Plugin
Open JDK, Oracle JDK 8 and 11 (but please note that Java 11.0.7 is NOT supported)

Spring Versions

CLI IntelliJ Plugin
Spring Boot 1.3.3+, Spring 4.2.5+

Build Tools

CLI IntelliJ Plugin
Maven 3.2.5+, Gradle 2.6+

Test Frameworks

CLI IntelliJ Plugin
JUnit 4.7 - 4.13, JUnit 5.0 - 5.7

Mock Frameworks

CLI IntelliJ Plugin
Mockito 1.9.5 - 3.10.0

Coverage Measurement

CLI IntelliJ Plugin
Externally via JaCoCo, SonarQube etc.

Creating Tests - Scope

CLI IntelliJ Plugin
Per method
Per class
Per package
This feature is not available for the IntelliJ Plugin Community Edition
Per module
Exclude methods from analysis

Incremental test updating

CLI IntelliJ Plugin
Use git diff patch file to update tests (


CLI IntelliJ Plugin
Export detailed JSON report


CLI IntelliJ Plugin
Web based dashboard


CLI IntelliJ Plugin
Zip bundle
Via JetBrains marketplace or customised install bundle


CLI IntelliJ Plugin
Anonymous usage data sent to Diffblue (can be turned off). For details, please see our Privacy Notice.