Cypress HTML-Validate plugin

Validates HTML using html-validate. It automatically fetches the active source markup from the browser and validates, failing the test if any validation errors is encountered.

Prerequisites

• NodeJS 14.17 or later.
• [email protected] or later.
• [email protected] or later.

Installation

npm install --save-dev html-validate cypress-html-validate

Make sure you install both html-validate and the plugin cypress-html-validate. With NPM 7 or later it will be satisfied by the peer dependency but for a more consistent and deterministic experience it is suggested to include both as dependencies for your project.

Usage

With Cypress 10 or later

Import the plugin:

import htmlvalidate from "cypress-html-validate/plugin";

Add the setupNodeEvents if it doesnt already exist (either in the e2e or component block):

export default defineConfig({
  e2e: {
    setupNodeEvents(on) {
      htmlvalidate.install(on);
    },
  },
});

Import the command in the support file (default cypress/support/e2e.[jt]s for E2E-tests and cypress/support/component.[jt]s for component tests):

import "cypress-html-validate/commands";

With earlier versions (pre v10)

Install the plugin in cypress/plugins/index.js:

const htmlvalidate = require("cypress-html-validate/plugin");

module.exports = (on) => {
  htmlvalidate.install(on);
};

Import the command in the support file cypress/support/index.js:

import "cypress-html-validate/commands";

In test files:

it("should be valid", () => {
  cy.visit("/my-page.html");
  cy.htmlvalidate();
});

To automatically run after each test you can use afterEach either in the spec file or in cypress/support/index.js:

afterEach(() => {
  cy.htmlvalidate();
});

Options may optionally be passed (both plugin options and html-validate configuration):

/* plugin option to exclude an element */
cy.htmlvalidate({
  exclude: [".ignore-me"],
});

/* html-validate config to disable a rule */
cy.htmlvalidate({
  rules: {
    "input-missing-label": "off",
  },
});

/* both options */
cy.htmlvalidate(
  {
    rules: {
      "input-missing-label": "off",
    },
  },
  {
    exclude: [".ignore-me"],
  }
);

Running without a subject validates the entire document (with exception of using configuration options include and exclude). If you use it on a subject only that element and its descendants are validated:

it("should be valid", () => {
  cy.visit("/my-page.html");
  cy.get("#my-fancy-element").htmlvalidate();
});

Configuration

html-validate and the plugin can configured globally in the install function:

/* html-validate configuration */
const config = {
  rules: {
    foo: "error",
  },
};

/* plugin options */
const options = {
  exclude: [],
  include: [],
  formatter(messages) {
    console.log(messages);
  },
};

htmlvalidate.install(on, config, options);

The default configuration extends html-validate:recommended and html-validate:document (see presets). This can be overridden by explictly specifying extends: []:

htmlvalidate.install(on, {
  extends: [],
});

See html-validate documentation for full description of configuration.

If you want to override per call you can pass configuration and/or options directly to the function:

cy.htmlvalidate([config], [options]);

Options

exclude: string[]

A list of selectors to ignore errors from. Any errors from the elements or any descendant will be ignored.

include: []

A list of selectors to include errors from. If this is set to non-empty array only errors from elements or any descendants will be included.

formatter

• type: (messages: Message[]): void

Custom formatter/reporter for detected errors. Default uses console.table(..) to log to console. Set to null to disable.

The original formatter can be imported with:

import { formatter } from "cypress-html-validate";