cypress-each

cypress-each

A demo of mocha-each and custom describe.each and it.each implementation for Cypress

Blog posts

• Dynamic API Tests Using Cypress-Each Plugin
• Refactor Tests To Be Independent And Fast Using Cypress-Each Plugin

Install and use

# install using NPM
$ npm i -D cypress-each
# install using Yarn
# yarn add -D cypress-each

Import cypress-each in a single spec or in Cypress support file

import 'cypress-each'
// now can use describe.each and it.each

Let's create a separate test for each selector from a list

import 'cypress-each'

// create a separate test for each selector
const selectors = ['header', 'footer', '.new-todo']
it.each(selectors)('element %s is visible', (selector) => {
  cy.visit('/')
  cy.get(selector).should('be.visible')
})
// creates tests
// "element header is visible"
// "element footer is visible"
// "element .new-todo is visible"

Multiple arguments

You can pass multiple arguments into the callback function by using an array of arrays. For example, to check if an element is visible, invisible, or exists, you can have both a selector and the assertion string for each item.

const data = [
  // each entry is an array [selector, assertion]
  ['header', 'be.visible'],
  ['footer', 'exist']
  ['.new-todo', 'not.be.visible']
]
it.each(data)('element %s should %s', (selector, assertion) => {
  cy.visit('/')
  cy.get(selector).should(assertion)
})
// creates tests
// "element header should be.visible"
// "element footer should exist"
// "element .new-todo should not.be.visible"

Test and suite titles

You can use the arguments to the test callback in the test title in order.

it.each([10, 20, 30])('number is %d', (x) => { ... })
// creates the tests
// "number is 10"
// "number is 20"
// "number is 30"

If you want to use the iteration variable in the title, use %k for zero-based index, or %K for one-based index.

it.each([10, 20, 30])('checking item %k', (x) => { ... })
// creates the tests
// "checking item 0"
// "checking item 1"
// "checking item 2"
it.each([10, 20, 30])('checking item %K', (x) => { ... })
// creates the tests
// "checking item 1"
// "checking item 2"
// "checking item 3"

Title function

You can form the test title yourself using a function. The function will get the item, the index, and all items and should return a string with the test title.

function makeTestTitle(s, k, strings) {
  return `test ${k + 1} for "${s}"`
}
it.each(['first', 'second'])(makeTestTitle, () => ...)
// creates the tests
// 'test 1 for "first"'
// 'test 2 for "second"'

It is very useful for forming a test title based on a property of an object, like

it.each([
  { name: 'Joe', age: 30 },
  { name: 'Mary', age: 20 },
])(
  (person) => `tests person ${person.name}`,
  (person) => { ... }
})
// creates the tests
// "tests person Joe"
// "tests person Mary"

See [cypress/integration/title-function.js](./cypress/integration/ title-function.js) for more examples

Chunking

There is a built-in chunking helper in describe.each and it.each to only take a subset of the items. For example, to split all items into 3 chunks, and take the middle one, use

it.each(items, 3, 1)(...)

The other spec files can take the other chunks. The index starts at 0, and should be less than the number of chunks.

// split all items among 3 specs
// spec-a.js
it.each(items, 3, 0)(...)
// spec-b.js
it.each(items, 3, 1)(...)
// spec-c.js
it.each(items, 3, 2)(...)

Examples

• Watch Using cypress-each To Create Separate Tests
• Read Dynamic API Tests Using Cypress-Each Plugin

Specs

Find the implementation in src/index.js

• it-spec.js uses no shortcuts to define multiple tests that are almost the same. We want to avoid the repetition
• it-each-spec.js uses the it.each helper to generate multiple it tests given a data array
• describe-each-spec.js uses describe.each helper to create describe blocks for each item in the given data array
• mocha-each-spec.js uses 3rd party mocha-each to generate it tests for each data item

Types

This package includes TypeScript definition for it.each and describe.each. Thus the parameter should be the right type from the array of values:

it.each([
  { name: 'Joe', age: 30 },
  { name: 'Mary', age: 20 },
])('has correct types', (user) => {
  // the type for the "user" should be
  // name: string, age: number
  expect(user).to.have.keys('name', 'age')
  expect(user.name).to.be.a('string')
  expect(user.age).to.be.a('number')
})

Include this module with other library types, like

{
  "compilerOptions": {
    "types": ["cypress", "cypress-each"],
  }
}

Or inside an individual spec file add

/// <reference types="cypress-each" />

Small print

Author: Gleb Bahmutov <[e-mail]> © 2021

• @bahmutov
• glebbahmutov.com
• blog
• videos
• presentations
• cypress.tips

License: MIT - do anything with the code, but don't blame me if it does not work.

Support: if you find any problems with this module, email / tweet / open issue on Github

MIT License

Copyright (c) 2021 Gleb Bahmutov <[e-mail]>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.