Add Cypress visual testing (#2471)

* add the travis-encrypted PERCY_TOKEN value pair, and a database bootstrap as part of the test setup

.gitignore

@@ -112,3 +112,6 @@ network-api/networkapi/frontend/*
 
 # PyCharm
 .idea/
+
+# Cypress visual regression testing
+cypress/videos

.travis.yml

@@ -14,10 +14,12 @@ install:
 - pipenv run python network-api/manage.py collectstatic --no-input
 before_script:
 - psql -c 'create database network;' -U postgres
+- ./release-steps.sh
 script:
 - npm test
 - pipenv run flake8 tasks.py network-api/
 - pipenv run coverage run --source './network-api/networkapi' network-api/manage.py test networkapi
+- npm run cypress
 after_success:
 - coveralls
 env:

cypress.json

@@ -0,0 +1,3 @@
+{
+  "baseUrl": "http://localhost:8000"
+}

cypress/fixtures/example.json

@@ -0,0 +1,5 @@
+{
+  "name": "Using fixtures to represent data",
+  "email": "hello@cypress.io",
+  "body": "Fixtures are a great way to mock data for responses to routes"
+}

cypress/integration/single-page.js

@@ -0,0 +1,10 @@
+describe('Integration test with visual testing', () => {
+  it('Loads the homepage', function() {
+
+    // Load the page or perform any other interactions with the app.
+    cy.visit(`/`);
+
+    // Take a snapshot for visual diffing
+    cy.percySnapshot();
+  });
+});

cypress/plugins/index.js

@@ -0,0 +1,17 @@
+// ***********************************************************
+// This example plugins/index.js can be used to load plugins
+//
+// You can change the location of this file or turn off loading
+// the plugins file with the 'pluginsFile' configuration option.
+//
+// You can read more here:
+// https://on.cypress.io/plugins-guide
+// ***********************************************************
+
+// This function is called when a project is opened or re-opened (e.g. due to
+// the project's config changing)
+
+module.exports = (on, config) => {
+  // `on` is used to hook into various events Cypress emits
+  // `config` is the resolved Cypress config
+}

cypress/support/commands.js

@@ -0,0 +1,27 @@
+// ***********************************************
+// This example commands.js shows you how to
+// create various custom commands and overwrite
+// existing commands.
+//
+// For more comprehensive examples of custom
+// commands please read more here:
+// https://on.cypress.io/custom-commands
+// ***********************************************
+//
+//
+// -- This is a parent command --
+// Cypress.Commands.add("login", (email, password) => { ... })
+//
+//
+// -- This is a child command --
+// Cypress.Commands.add("drag", { prevSubject: 'element'}, (subject, options) => { ... })
+//
+//
+// -- This is a dual command --
+// Cypress.Commands.add("dismiss", { prevSubject: 'optional'}, (subject, options) => { ... })
+//
+//
+// -- This is will overwrite an existing command --
+// Cypress.Commands.overwrite("visit", (originalFn, url, options) => { ... })
+
+import '@percy/cypress';

cypress/support/index.js

@@ -0,0 +1,20 @@
+// ***********************************************************
+// This example support/index.js is processed and
+// loaded automatically before your test files.
+//
+// This is a great place to put global configuration and
+// behavior that modifies Cypress.
+//
+// You can change the location of this file or turn off
+// automatically serving support files with the
+// 'supportFile' configuration option.
+//
+// You can read more here:
+// https://on.cypress.io/configuration
+// ***********************************************************
+
+// Import commands.js using ES2015 syntax:
+import './commands'
+
+// Alternatively you can use CommonJS syntax:
+// require('./commands')

package.json

@@ -14,6 +14,8 @@
     "build:sass": "shx mkdir -p network-api/networkapi/frontend/_css && node-sass source/sass/main.scss network-api/networkapi/frontend/_css/main.compiled.css && node-sass source/sass/buyers-guide/bg-main.scss network-api/networkapi/frontend/_css/buyers-guide.compiled.css && npm run autoprefix",
     "build": "npm run build:common && npm run build:js",
     "build-uncompressed": "npm run build:common && npm run build:js-uncompressed",
+    "cypress": "run-p --race server cypress:test",
+    "cypress:test": "wait-on tcp:8000 && cypress run",
     "heroku-postbuild": "npm run build",
     "migrate": "pipenv run python network-api/manage.py migrate",
     "optimize:svg": "find source/images -type f -name '*.svg' -print0 | xargs -0 -n 1 -P 6 svgo --multipass --pretty --enable=removeTitle",
@@ -77,5 +79,10 @@
   },
   "engines": {
     "node": "^8.9.0"
+  },
+  "devDependencies": {
+    "@percy/cypress": "^0.2.3",
+    "cypress": "^3.1.4",
+    "wait-on": "^3.2.0"
   }
 }