Custom JavaScript testing framework

This is a custom JS testing framework similar in essence to the broadly known jest framework.

The goal of re-implementing jest fom scratch was to be able to capture the essence of its underlying principles.

This project was based on Mathieu Eveillard's idea.

Getting started

# Install dependencies
npm install

# Run one test file
npm test ./sample-test-files/sample.test.ts

# Run multiple test files
npm run run-test-list ./sample-test-files/sam*.ts

Sample output

Hereafter is the output we currently get when running the test on a sample file.

$ npm test ./sample-test-files/sample.test.ts

> typescript-kata-starter@1.0.0 test
> ts-node "./sample-test-files/sample.test.ts"


--------- Some tests are skipped ----------
✅ Test that passes
❌ Test that fails
      Expected: 12
      But got: 11
⚠️  ERROR IN TEST Test that throws an error !!
      Got the following error: Error: I throw an error

--------- Only `only` should run ----------
❌ Only test that should be run (test1)
      Expected: 12
      But got: 11
❌ Only test that should be run (test2)
      Expected: 12
      But got: 11

--------- Tests with mocks ----------
✅ Test on expectToHaveBeenCalled that should pass as it has been called
✅ Test on expectToHaveBeenCalled that should pass as it has been called twice
❌ Test on expectToHaveBeenCalled that should fail as the dependency has *NOT* been called
      Expected to have been called at least once.
      But got called 0 times.
✅ Test on expectToHaveBeenCalled that should pass as it has been called 3 times
❌ Test on expectToHaveBeenCalled that should fail as it has been called 3 times
      Expected to have been called 2 times.
      But got called 3 times.

File organization

The framework is in the src/ folder.

The sample-test-files/ folder contains sample test files, defined in the format understandable by this custom testing library.

Features list

• Display failing tests
• Display unexpected errors
• Add a skip feature to tests
• Add a modulator: either skip OR only
• Add a describe option
• Add a skip option on describe sections
• Add a function emulator (mock feature)
• Allow to compare objects (not only scalars - cf expectEqual)
• Display full report
• Pass test files as parameters
• Exit on fail