Tag Archives : mutation testing


How well is it tested: Puppet (part 2 of 2)

In the last post, I showed analysis results of Puppet’s test duplication along with other interesting findings. The relationships discovered seem to suggest that test duplication is not due to chance alone, and that there is a complex relationship in terms of amount of tests in the suites that is not entirely linear. The results in the post also […]

Test duplication vs mutation score (log-scaled and reversed)

Mutator now supports multiple source files!

You asked, we listened! We heard you loud and clear and we are thrilled to introduce multi-source support for Mutator! Previously, Mutator only allowed one source file per test suite using the assumption that each test suite had one and only one source (a.k.a. system under test, or SUT). This original design choice was deliberately made partly to encourage […]


How well is it tested: Composer

Composer is a very popular dependency manager that many PHP projects use. With the newly introduced support for PHP by Mutator, I set off to rate the quality of Composer. For the analysis, I utilized the Composer snapshot of version 1.0-dev, from Aug 24 2015. Recall that the mutation score of a test suite is a quality metric […]

95% confidence interval for Composer's test quality

Mutator now supports PHP!

Create world-class PHP apps with Mutator Working on a PHP project? Then this is what you were waiting for! With Mutator, you can finally rate and improve the quality of your PHP projects reliably!     Mutator uses mutation analysis — an extremely reliable technique that is more robust than code coverage — to find and improve the quality of your tests. Check out […]


Mutator is now Free!

Mutator was created with a simple objective: to improve the quality of software. The companies listed in Mutator’s page have already delivered higher quality products and apps by using it. But what about developers like you that still rely on the outdated and inaccurate code coverage metric? Whether you are a freelancer, or working in a small shop, or even in a huge team […]


How well is it tested: Mutant

This time, Mutator analyzes another mutation testing tool for Ruby called Mutant. Mutant is an alternative to mutation analysis for Ruby projects. It is fast because it applies mutations on the abstract syntax tree. However, Mutant has several disadvantages. First, since it goes under the Ruby hood, it only supports Ruby exclusively and, second, it only support […]

Mutant's test quality