Mutation Tester

This extension provides a mutation tester for C#.

The Project

This is part of a honours degree project to develop a C# mutation testing tool.
It builds upon a previous masters degree project by Le Duc Quy.
The project supervisor is Dr Tim Storer Timothy.Storer@glasgow.ac.uk

Mutation Testing Overview

Mutation Testing is a technique that can be used to assess overall test suite quality. It runs the test suite against many versions of the code that have been altered in some way, called mutants. These mutants are classified as either 'Killed' if any test failed or 'Survived' if all tests passed. Surviving mutants represent a way the code could be changed without causing the tests to fail. There are two main reasons for surviving mutants:

• There is a test that can be added to the test suite to kill this mutant
• The mutant is equivalent to the original code. For example, x <= y and !(x > y)

It is down to a developer's judgement to decide whether a surviving mutant is equivalent or not and whether writing tests to kill mutants is of benefit.

#####Warning

This tool may take a long time (weeks) to execute on large projects and it is advised to only use it on smaller projects.

Using the tool

Opening the tool

You can open the tool's window from the menu. View -> Other Windows -> Mutation Testing

Choosing project to test

Load the project and solution you want to test into Visual Studio. Press the 'Get current setup' button. The tool should now display a path to the solution file (.sln) and the filename of the .exe or .dll the project produces.

Running the mutation tester

When you are happy with the selected files, press the 'run' button on the tool. The tool will keep you updated on its progress but may take a little time to get going.

Cancelling a run

If a run is taking too long, press the cancel button, all progress on the current mutation testing run is lost when it is cancelled.

Results

One running is complete select a class from the drop down menu then 'Show surviving mutants'. Areas of code that contain surviving mutants will be highlighted in red, hover over those areas to get a list of all the mutants in that area survived.