Add tests for download

cypress/integration/2-create-pages/download.cypress.js

@@ -0,0 +1,18 @@
+import { download } from '../utils'
+
+describe('download page', () => {
+  beforeEach(() => {
+    cy.visit('/docs/tutorials-and-examples')
+  })
+
+  it('loaded ok', () => {
+    cy.get('a[data-link="download"]')
+      .should('contains.text', 'Download the Prototype Kit (zip file)')
+      .click()
+
+    cy.get('details a span')
+      .first()
+      .should('contains.text', 'Source code')
+      .then(download({ timeout: 60000 }))
+  })
+})

cypress/integration/utils.js

@@ -8,7 +8,37 @@ const waitForApplication = async () => {
     .should('contains.text', 'Prototype your service using GOV.UK Prototype Kit')
 }
 
+const getFilename = ({ currentTarget }) => currentTarget.location.pathname
+  .split('/')
+  .pop()
+  .replace('v', 'govuk-prototype-kit-') + '.zip'
+
+/*   Based on the workaround examples here: https://github.com/cypress-io/cypress/issues/14857  */
+const download = ({ timeout }) => (element) => {
+  cy.window().document().then(doc => {
+    doc.addEventListener('click', async (event) => {
+      const downloadsFolder = Cypress.config('downloadsFolder')
+      const filename = getFilename(event)
+      await sleep(1000)
+      cy.task('downloaded', { filename, downloadsFolder })
+      await sleep(1000)
+      cy.task('installApp', { timeout })
+      doc.location.reload()
+    })
+
+    /* Make sure the file exists */
+    cy.intercept('/', (req) => {
+      req.reply((res) => {
+        expect(res.statusCode).to.equal(200)
+      })
+    })
+
+    element.click()
+  })
+}
+
 module.exports = {
+  download,
   sleep,
   waitForApplication
 }

cypress/plugins/index.js

@@ -14,20 +14,60 @@
 // const spawn = require('child_process').spawn
 const fs = require('fs')
 const path = require('path')
-
 const waitOn = require('wait-on')
+const extract = require('extract-zip')
+const { exec } = require('child_process')
 
 const { sleep } = require('../integration/utils')
+const { waitUntilFileExists } = require('../../lib/utils')
 
 const createFolderForFile = (filepath) => {
-  const dir = filepath.substring(0, filepath.lastIndexOf('/'))
+  const separator = (filepath.indexOf('/') > -1) ? '/' : '\\'
+  const dir = filepath.substring(0, filepath.lastIndexOf(separator))
   if (dir && !fs.existsSync(dir)) {
     fs.mkdirSync(dir, {
       recursive: true
     })
   }
 }
 
+const validateExtractedVersion = extractFolder => {
+  // Retrieve the name and version from the package.json from the extracted zip file
+  const data = fs.readFileSync(path.join(extractFolder, 'package.json'))
+  const { name, version } = JSON.parse(data)
+  // Retrieve the directory name of the extracted files
+  const separator = (extractFolder.indexOf('/') > -1) ? '/' : '\\'
+  const dirname = extractFolder.substring(extractFolder.lastIndexOf(separator) + 1)
+  // Make sure they match
+  if (`${name}-${version}` !== dirname) {
+    throw new Error(`Extracted folder ${extractFolder} contains wrong version in package.json >> ${name}-${version}`)
+  }
+}
+
+const waitForDownload = async (filename, previousModified = -1) => {
+  return new Promise((resolve) => {
+    const exists = fs.existsSync(filename)
+    const currentModified = exists ? fs.statSync(filename).mtime.getTime() : previousModified - 1
+    if (previousModified !== currentModified) {
+      setTimeout(() => waitForDownload(filename, currentModified).then(resolve), 100)
+    } else {
+      resolve()
+    }
+  })
+}
+
+const performInstall = async ({ folder }) => {
+  exec(`cd ${folder} && npm install`, (err, stdout, stderr) => {
+    if (err) {
+      throw new Error(err.message)
+    } else {
+    // the *entire* stdout and stderr (buffered)
+      console.log(`stdout: ${stdout}`)
+      console.log(`stderr: ${stderr}`)
+    }
+  })
+}
+
 /**
  * @type {Cypress.PluginConfig}
  */
@@ -42,7 +82,22 @@ module.exports = (on, config) => {
   const waitUntilAppRestarts = async (timeout) => await waitOn({ delay: 2000, resources: [config.baseUrl], timeout })
 
   on('task', {
-    copyFile: async ({ source, target, timeout = 2000 }) => {
+    downloaded: async ({ filename, downloadsFolder }) => {
+      try {
+        const fullFilename = path.join(downloadsFolder, filename)
+        await waitForDownload(fullFilename)
+        await extract(fullFilename, { dir: downloadsFolder })
+        const extractFolder = fullFilename.substring(0, fullFilename.lastIndexOf('.zip'))
+        validateExtractedVersion(extractFolder)
+        return Promise.resolve(null)
+      } catch (err) {
+        return Promise.reject(err)
+      }
+    }
+  })
+
+  on('task', {
+    copyFile: async ({ source, target }) => {
       try {
         createFolderForFile(target)
         fs.copyFileSync(source, target)
@@ -56,6 +111,24 @@ module.exports = (on, config) => {
     }
   })
 
+  on('task', {
+    installApp: async ({ timeout }) => {
+      try {
+        const downloadsFolder = path.join('cypress', 'downloads')
+        const files = fs.readdirSync(downloadsFolder)
+        if (files.length) {
+          const folder = path.join(downloadsFolder, files[0])
+          await performInstall({ folder })
+          const filename = path.join(folder, 'node_modules', 'govuk-frontend', 'package.json')
+          await waitUntilFileExists(filename, timeout)
+        }
+        return Promise.resolve(null)
+      } catch (err) {
+        return Promise.reject(err)
+      }
+    }
+  })
+
   on('task', {
     createFile: async ({ filename, data, replace = false }) => {
       try {

package.json

@@ -54,6 +54,7 @@
   "optionalDependencies": {
     "cypress": "^9.6.0",
     "eslint-plugin-cypress": "^2.12.1",
+    "extract-zip": "^2.0.1",
     "glob": "^7.1.4",
     "jest": "^27.3.1",
     "standard": "^14.3.3",