feat(client): Add email prefill on the /signin page if the email ad…

…dress is passed as a search parameter.

app/scripts/views/sign_in.js

@@ -33,10 +33,15 @@ function (_, p, BaseView, FormView, SignInTemplate, Constants, Session, Password
     },
 
     context: function () {
+      // Session.prefillEmail comes first because users can edit the email,
+      // go to another screen, edit the email again, and come back here. We
+      // want the last used email.
+      var email = Session.prefillEmail || Url.searchParam('email', this.window.location.search);
+
       return {
         service: this.service,
         serviceName: this.serviceName,
-        email: Session.prefillEmail,
+        email: email,
         password: Session.prefillPassword,
         isSync: Session.isSync()
       };

app/tests/spec/views/sign_in.js

@@ -22,17 +22,21 @@ function (chai, $, p, View, Session, AuthErrors, Metrics, WindowMock, RouterMock
   var wrapAssertion = TestHelpers.wrapAssertion;
 
   describe('views/sign_in', function () {
-    var view, email, routerMock, metrics;
+    var view, email, routerMock, metrics, windowMock;
 
     beforeEach(function () {
       email = 'testuser.' + Math.random() + '@testuser.com';
 
+      Session.clear();
+
       routerMock = new RouterMock();
+      windowMock = new WindowMock();
       metrics = new Metrics();
 
       view = new View({
         router: routerMock,
-        metrics: metrics
+        metrics: metrics,
+        window: windowMock
       });
 
       return view.render()
@@ -63,6 +67,16 @@ function (chai, $, p, View, Session, AuthErrors, Metrics, WindowMock, RouterMock
       });
     });
 
+
+    it('prefills email with email from search parameter if Session.prefillEmail is not set', function () {
+      windowMock.location.search = '?email=' + encodeURIComponent('testuser@testuser.com');
+
+      return view.render()
+          .then(function () {
+            assert.equal(view.$('[type=email]').val(), 'testuser@testuser.com');
+          });
+    });
+
     describe('updatePasswordVisibility', function () {
       it('pw field set to text when clicked', function () {
         $('.show-password').click();

app/tests/spec/views/sign_up.js

@@ -92,7 +92,6 @@ function (chai, _, $, p, View, Session, AuthErrors, Metrics, RouterMock, WindowM
 
         return view.render()
             .then(function () {
-              assert.ok($('#fxa-signup-header').length);
               assert.equal(view.$('[type=email]').val(), 'testuser@testuser.com');
             });
       });