Scenario: A user has an existing prototype and tries to follow our

standard upgrade path but fails to copy the changes made in `/app`

- Stylesheets > Still uses node_modules directly in the backend before
                being compiled to application.css

- scripts > `govuk-frontend/all.js` was not loading in the browser. I had
            to reintroduce the route to `node_modules/govuk-frontend` to
            server.js so that the file could be served to the browser.
            I have written tests for this scenario to ensure it is not an
            issue in the future. It could be tidied up once we finalise
            extensions and move it out of experimental.

Author: Alistair Laing

__tests__/spec/sanity-checks.js

@@ -45,46 +45,65 @@ describe('The Prototype Kit', () => {
     })
   })
 
-  it('should allow known assets to be loaded from node_modules', function (done) {
-    request(app)
-      .get('/extension-assets/govuk-frontend/all.js')
-      .expect('Content-Type', /application\/javascript; charset=UTF-8/)
-      .expect(200)
-      .end(function (err, res) {
-        if (err) {
-          done(err)
-        } else {
-          assert.strictEqual('' + res.text, readFile('node_modules/govuk-frontend/all.js'))
-          done()
-        }
-      })
-  })
+  describe('extensions', () => {
+    it('should allow known assets to be loaded from node_modules', (done) => {
+      request(app)
+        .get('/extension-assets/govuk-frontend/all.js')
+        .expect('Content-Type', /application\/javascript; charset=UTF-8/)
+        .expect(200)
+        .end(function (err, res) {
+          if (err) {
+            done(err)
+          } else {
+            assert.strictEqual('' + res.text, readFile('node_modules/govuk-frontend/all.js'))
+            done()
+          }
+        })
+    })
 
-  it('should allow known assets to be loaded from node_modules', function (done) {
-    request(app)
-      .get('/assets/images/favicon.ico')
-      .expect('Content-Type', /image\/x-icon/)
-      .expect(200)
-      .end(function (err, res) {
-        if (err) {
-          done(err)
-        } else {
-          assert.strictEqual('' + res.body, readFile('node_modules/govuk-frontend/assets/images/favicon.ico'))
-          done()
-        }
-      })
-  })
+    it('should allow known assets to be loaded from node_modules', (done) => {
+      request(app)
+        .get('/assets/images/favicon.ico')
+        .expect('Content-Type', /image\/x-icon/)
+        .expect(200)
+        .end(function (err, res) {
+          if (err) {
+            done(err)
+          } else {
+            assert.strictEqual('' + res.body, readFile('node_modules/govuk-frontend/assets/images/favicon.ico'))
+            done()
+          }
+        })
+    })
+
+    it('should not expose everything', function (done) {
+      request(app)
+        .get('/assets/common.js')
+        .expect(404)
+        .end(function (err, res) {
+          if (err) {
+            done(err)
+          } else {
+            done()
+          }
+        })
+    })
 
-  it('should not expose everything', function (done) {
-    request(app)
-      .get('/assets/common.js')
-      .expect(404)
-      .end(function (err, res) {
-        if (err) {
-          done(err)
-        } else {
-          done()
-        }
+    describe('misconfigured prototype kit - while upgrading kit developer did not copy over changes in /app folder', () => {
+      it('should still allow known assets to be loaded from node_modules', (done) => {
+        request(app)
+          .get('/node_modules/govuk-frontend/all.js')
+          .expect('Content-Type', /application\/javascript; charset=UTF-8/)
+          .expect(200)
+          .end(function (err, res) {
+            if (err) {
+              done(err)
+            } else {
+              assert.strictEqual('' + res.text, readFile('node_modules/govuk-frontend/all.js'))
+              done()
+            }
+          })
       })
+    })
   })
 })

server.js

@@ -111,6 +111,9 @@ app.set('view engine', 'html')
 // Middleware to serve static assets
 app.use('/public', express.static(path.join(__dirname, '/public')))
 
+// Serve govuk-frontend in from node_modules (so not to break pre-extenstions prototype kits)
+app.use('/node_modules/govuk-frontend', express.static(path.join(__dirname, '/node_modules/govuk-frontend')))
+
 // Set up documentation app
 if (useDocumentation) {
   var documentationViews = [