mutation-tests's Introduction

mutation-tests

This project is an example of mutation tests with Stryker.
We have a simple method that returns true or false, and we create a test for this method. We have 100% code coverage, but we don't have coverage of all the scenarios.
Look at the Stryker page and get more information about it.

Stryker mutation report (on Github pages)

Getting Started

Install the dependencies:

npm install

Compile TypeScript:

npm run build

Running tests

Run tests using Jest:

npm run test

 PASS  dist/test/elections.test.js
  ✓ An 27-year-old cannot be a president (1 ms)
  ○ skipped An 35-year-old can be a president

--------------|---------|----------|---------|---------|-------------------
File          | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line  s
--------------|---------|----------|---------|---------|-------------------
All files     |     100 |      100 |     100 |     100 |
 elections.ts |     100 |      100 |     100 |     100 |
--------------|---------|----------|---------|---------|-------------------

Running mutation tests

Run tests using Stryker:

npm run mutation:test

Ran all tests for this mutant.
Ran 1.00 tests per mutant on average.
--------------|---------|----------|-----------|------------|----------|---------|
File          | % score | killed   | timeout   | survived   | no cov   | error   |
--------------|---------|----------|-----------|------------|----------|---------|
All files     |   60.00 |        3 |         0 |          2 |        0 |       0 |
 elections.ts |   60.00 |        3 |         0 |          2 |        0 |       0 |
--------------|---------|----------|-----------|------------|----------|---------|

Note: There is a test in skip mode, if you remove this skip, we will get 100% coverage after the mutation.