Mathew Lodge, CEO of Diffblue: An innovative leader changing the way software is developed using Artificial Intelligence

Diffblue spun out of the University of Oxford in 2016 and has raised $32m of venture financing to date. Investors include IP Group, Oxford Science Enterprises, Goldman Sachs and Oxford University. Diffblue is headquartered in Oxford, UK. Diffblue Cover, the company’s first product, automatically writes tests for Java code to enable development teams to deliver higher quality software, faster. Diffblue’s technology is developed by their team of leading experts in software verification and synthesis. Their customers include JP Morgan, Citi, Goldman Sachs and Amazon Web Services. Their culture is based on independence, accountability, collaboration and intellectual curiosity. They encourage an open and diverse environment that gives their people the tools needed to grow personally and professionally.

Diffblue Cover: Autonomous Java Unit Test Writing with AI for Code

Diffblue Cover gives enterprises and Java developers the means to unlock more value from unit testing, the key enabler of fast delivery of high-quality code. Its core technology uses AI to autonomously write JUnit tests that are indistinguishable from those created by a developer. A range of additional features leverage this AI for Code platform to further increase coverage, accelerate development and reduce risk. Cover operates at high speed: it can write more tests in hours than a typical developer could create in a full year, and automatically update your entire unit test library whenever subsequent code changes are made. For new or existing code, on the desktop or embedded in a CI pipeline, Cover eliminates tedious, repetitive, error-prone work from developer workloads. Diffblue Cover writes unit tests at the click of a button so developers can spend their time on more creative work. Diffblue Cover quickly writes tests for large legacy codebases, and identifies untestable code that should be refactored.

Diffblue Cover’s key features are built on the foundation of the product’s central AI for Code technology.

• Diffblue Cover Core automatically writes and maintains Java unit tests. Cover Core is available in all versions of Diffblue Cover;
• Diffblue Cover Reports visualizes the state of unit testing and pinpoints actionable insights that improve quality and efficiency;
• Diffblue Cover Optimize cuts unit test execution time, for faster feedback, quicker deployment and lower costs;
• Diffblue Cover Refactor improves existing code by making it more testable, automatically increasing test coverage.

Crucially, Cover’s code-writing technology - based on reinforcement learning rather than generative ‘transformer’ models - operates completely autonomously, without the manual intervention required by some other AI-assisted coding tools. Cover doesn’t just suggest code that might work for you - it writes new code completely automatically. The unit tests it produces accurately reflect the current behavior of your code and are ready to compile and run without developer intervention.

Keeping Your Code Secure

Cover recognizes the importance of security to every business - and particularly those in highly competitive or regulated industries - Cover runs entirely within your local user environment. Diffblue Cover only relies on code your developers have written for your Java applications. It never uses code from other sources, like open source repositories. This fact, combined with a deterministic reinforcement learning approach to unit test writing, means that no connections to external servers are required. With Diffblue Cover no data needs to leave your network. Diffblue Cover analyzes your existing Java program and writes unit regression tests that reflect the current behavior of the code. Then when your code's behavior changes, Diffblue Cover's tests alert you. Diffblue Cover can be installed on Linux, Windows and MacOS and runs 100% locally within your user environment. IntelliJ plugin and CLI options are available. You can run Cover on your entire Java project, just one class, or anything in between (it gets your project structure and dependencies from Maven or Gradle). Cover supports Spring Java apps and writes tests that use standard Spring idioms and mocking.

CLI Tool

Advanced Cover users prefer the CLI tool. It's more powerful, scriptable, and can generate tests for entire projects with a single command. The CLI tool works 100% autonomously, configuring itself from your Maven or Gradle environment. The power of Cover’s CLI is what allows it to be added to a CI pipeline. Each time a pull request is opened Cover can automatically create, execute and update your unit test library at appropriate points in the process. CI integration is the most scalable, reliable, repeatable option: unit testing becomes an effortless part of your workflow.

IntelliJ Plugin

The IntelliJ IDEA plugin generates tests per method or per class within the IDE. The plugin can be used for interactive test writing on the developer desktop, and supports test-driven development (TDD) by quickly generating unit regression tests for utility code in bulk — so you can focus on unit tests that cover the complex, critical business logic, and spend more time writing testable code.

About | Mathew Lodge

Mathew Lodge is the Chief Executive Officer of Diffblue. He has over twenty-five years of experience in the software industry in developer, product and marketing roles. Before joining Diffblue, his titles included SVP at Anaconda and Vice President of Cloud Services at VMWare. In each role, his focus is on building and marketing products that customers love.

"Cover is the only fully-automated, AI-powered solution that can automatically write new Java code, improve existing code, accelerate CI pipelines and provide deep insights into the risk of change."