cypress-benchmark

A simple Cypress plugin to run benchmark tests.

Cypress is not meant to be used as a performance testing tool since it has some overhead that causes things to run slower. However, if you're already using Cypress and want to get some benchmarks on the performance of your app, this will at least give you a good starting point.

Setup

npm install --save-dev cypress-benchmark

There are 3 parts to this plugin package, the plugin, the commands, and the test wrapper.

plugin

Setup the plugin in your plugins file

let setupPlugin = require('cypress-benchmark/plugin')

module.exports = (on, config) => {
    /**
     * ...other plugins
     */
    setupPlugin(on)
}

If you don't already have a plugins file (typically cypress/plugins/index.js), create one with the snippet above. See https://on.cypress.io/plugins-guide for details.

commands

Import the commands in your support file.

import commands from 'cypress-benchmark/commands'

This is typically in cypress/support/index.js. See https://on.cypress.io/configuration for details.

Test wrapper

In your spec files, you can now import cypress-benchmark, and use it as if it were the global it method:

import benchmark from 'cypress-benchmark';

benchmark('My Benchmark Test', () => {
    cy.visit('...')

    cy.mark('start')
    /**
     * ...perform actions to measure
     */
    cy.mark('end')

    cy.measure('Data load time', 'start', 'end')
})

An alternative to importing the test wrapper in every spec file is to add it to the global scope in the support file where you would import commands:

import benchmark from 'cypress-benchmark';

global.benchmark = benchmark;

Now you should have benchmark available globally just like it and describe.

Usage

benchmark(name, [options], test)

Runs a test and compiles measures recorded in the test.

name: String

Required

Name of the benchmark, similar in hierarchy to a describe

options: Object

An optional set of parameters described below.

test: Function

Required

The test function to run.

benchmark should be used in conjunction with the support commands cy.mark and cy.measure which are just wrappers for the respective performance methods.

import benchmark from 'cypress-benchmark';

benchmark('My Benchmark Test', () => {
	cy.visit('/');

	cy.mark('start1');
	/**
	 * ...perform actions to measure
	 */
	cy.mark('end1');

	cy.mark('start2');
	/**
	 * ...perform some other actions to measure
	 */
	cy.mark('end2');

	cy.measure('Measure 1', 'start1', 'end1');
	cy.measure('Measure 2', 'start2', 'end2');
});

Should result in something like this in your output file:

{
	"My Benchmark Test": {
		"Measure 1": [
			41.505000030156225,
		],
		"Measure 2": [
			43.69500000029802
		]
	}
}

Options

benchmark supports an optional second parameter which allows the following options to be set:

merge: Boolean

Default: true

Determines if the new results should be merged in with the existing results. Setting to false will overwrite the output file.

runCount: Number

Default: 1

Number of times to run the test

outPath: String

Default: 'benchmark.json'

File path to write the results to. The path is relative to the Cypress root.

Support commands

The two support commands cy.mark and cy.measure simply call the respective methods from performance.