Vtest - A very simple test library

Thinking about how a test library works I decided to create my own test library using TypeScript, taking inspiration from the functionality and design of existing libraries such as Jest. The code is available for anyone to clone and learn from.

Run Locally

Clone the project

git clone https://github.com/Andre0n/vtest

Go to the project directory

cd vtest

Install dependencies

npm install

Compiling the code

npm run build

Usage/Examples

Running the tests.

npm test

Now let's dive into the tests.js file.

Basic usage of this lib

• Create a basic test suite

const vtest = require('./vtest');

const my_suite = new vtest.TestSuite("Test Suite Example");

• Use the function add_test to create a new test

my_suite.add_test("1 + 1 should be 2");

• This function returns the expect() function that returns matchers like toBe() that compares whether two elements are equals.

my_suite
  .add_test(" 1 + 1 should be 2")
  .expect(() => {
    return 1 + 1;
  })
  .toBe(2);

my_suite
  .add_test(" 'aabb' == 'aabb' ")
  .expect(() => {
    return "aabb";
  })
  .toBe("aabb");

• The toBe has a variant the notBe

my_suite
  .add_test("2 - 1 should not be 3")
  .expect(() => {
    return 2 - 1;
  })
  .notBe(3);

Other important matchers

• The toBeDefined

my_suite
  .add_test("check if was defined")
  .expect(() => {
    return {};
  })
  .toBeDefined();

• The toBeCloseTo

my_suite
  .add_test("check if 0.1 + 0.2 is close to 0.3")
  .expect(() => {
    return 0.1 + 0.2;
  })
  .toBeCloseTo(0.3);

• The toBeNull

my_suite
  .add_test("check if is null")
  .expect(() => {
    return null;
  })
  .toBeNull();

• The notBeNull

my_suite
  .add_test("check if is not null")
  .expect(() => {
    return null;
  })
  .notBeNull();

Checking the results

To print test results the TestSuite object has the report() method.

my_suite.report();

Output

Our example will produce the following result

Test Suite Example
  ✔  1 + 1 should be 2
  ✔  'aabb' == 'aabb'
  ✔ 2 - 1 should not be 3
  ✔ check if was defined
  ✔ check if 0.1 + 0.2 is close to 0.3
  ✔ check if is null
  ✖ check if is not null  notBeNull: The object is null
         >> Expected: any  Got: null <<

Tests:  Passed: 6, Failed: 1, Total: 7

License

MIT

Authors

• @Andre0n