jest-test-each

jest-test-each

This package will help you to run parametrised tests easily [typesafe] without text tables or arrays of arrays.

Test environment can be overridden (by default it is jest)

Table of Contents

1. Examples
2. Setup
3. Features
4. What's next

Examples

Simple

its('roundings')
  .each([
    { input: 0, expected: '0' },
    { input: 0.99, expected: '1' },
    { input: 102.99998, expected: '103' },
    { input: -6, expected: '-6' },
  ])
  .run(t => {
    expect(Math.round(t.input).toFixed(0)).toBe(t.expected);
  });

Run test in idea with jest plugin:

More complex

its('check calculator')
  .each([
    { a: 1, b: 2, exp: [3, -1, 2, 0.5] },
    { a: 1, b: 0, exp: [1, 1, 0, Infinity] },
  ])
  .each(t => [
    { sign: '+' as const, exp: t.exp[0] },
    { sign: '-' as const, exp: t.exp[1] },
    { sign: '*' as const, exp: t.exp[2] },
    { sign: '/' as const, exp: t.exp[3] },
  ])
  .each(t => [{ flatDesc: `${t.a} ${t.sign} ${t.b} should be ${t.exp}` }])
  .run(async t => {
    expect(calc(t.a, t.b, t.sign)).toBe(t.exp);
  });

and the same test with auto cases names:

Setup

Install dev dependency:

yarn add -D jest-test-each

Add the following into your setupFilesAfterEnv config jest.setup.js file:

require('jest-test-each');

Looking a way to improve this. Can anyone help ?)

for .ts tests to see globals 'its' and 'Test' add the following to your tsconfig:

// tsconfig.json
 "include": [
    ...
    "node_modules/jest-test-each/dist/index.d.ts"
  ]

Additional

You can override test runner environment (by default it is jest env) by the following:

TestEachEnv({
  suiteRunner: describe,
  testRunner: it,
  beforeAll: beforeAll,
  ...
});

Features

• cases multiplication (.each().each()....run())
• ability to setup test-each:
  • number cases or not
  • group each level by suite or not
• ability to setup test runner environment (by default it is jest)
• ability to specify description for each case as function depending on case args
• ability to create .each level depending on previous
• ability to have flat tests cases (not groupped) when each case has 'flatDesc'
• global var 'Test' (or 'its' alias) to access test each (I'm accepting suggestions on namings)
• ability to run without single .each (its('foo').run(..))
• To run one test from TestEach like it.only (.only(<filter>))
• To start testEach by Idea plugin (workaround: wrap with describe and do not put name into Test Each)

What's next

• add '.before' to testEach with disposable interface for automatic cleanup
• do not create suite wrapping when only one test in the group
• add ability to skip test if it is marked by defect