diff --git a/app/assets/javascripts/previewPane.js b/app/assets/javascripts/previewPane.js
index 7a8172861..514b02274 100644
--- a/app/assets/javascripts/previewPane.js
+++ b/app/assets/javascripts/previewPane.js
@@ -1,9 +1,8 @@
-(function () {
+(function (global) {
 
   'use strict';
 
-  const root = this,
-      $ = this.jQuery;
+  $ = global.jQuery;
 
   let branding_style = $('.multiple-choice input[name="branding_style"]:checked');
 
@@ -34,4 +33,4 @@
   $form.find('button[type="submit"]').text('Save');
 
   $('fieldset').on('change', 'input[name="branding_style"]', setPreviewPane);
-})();
+})(window);
diff --git a/tests/javascripts/previewPane.test.js b/tests/javascripts/previewPane.test.js
new file mode 100644
index 000000000..dd25031dc
--- /dev/null
+++ b/tests/javascripts/previewPane.test.js
@@ -0,0 +1,234 @@
+const helpers = require('./support/helpers.js');
+
+const emailPageURL = '/services/6658542f-0cad-491f-bec8-ab8457700ead/service-settings/set-email-branding';
+const emailPreviewConfirmationURL = '/services/6658542f-0cad-491f-bec8-ab8457700ead/service-settings/preview-email-branding';
+const letterPageURL = '/services/6658542f-0cad-491f-bec8-ab8457700ead/service-settings/set-letter-branding';
+const letterPreviewConfirmationURL = '/services/6658542f-0cad-491f-bec8-ab8457700ead/service-settings/preview-letter-branding';
+
+let locationMock;
+
+beforeAll(() => {
+
+  // mock calls to window.location
+  // default to the email page, the pathname can be changed inside specific tests
+  locationMock = new helpers.LocationMock(emailPageURL);
+
+});
+
+afterAll(() => {
+
+  // reset window.location to its original state
+  locationMock.reset();
+  require('./support/teardown.js');
+
+});
+
+describe('Preview pane', () => {
+
+  let form;
+  let radios;
+
+  beforeEach(() => {
+
+    const brands = {
+      "name": "branding_style",
+      "label": "Branding style",
+      "cssClasses": [],
+      "fields": [
+        {
+          "label": "Department for Education",
+          "value": "dfe",
+          "checked": true
+        },
+        {
+          "label": "Home Office",
+          "value": "ho",
+          "checked": false
+        },
+        {
+          "label": "Her Majesty's Revenue and Customs",
+          "value": "hmrc",
+          "checked": false
+        },
+        {
+          "label": "Department for Work and Pensions",
+          "value": "dwp",
+          "checked": false
+        }
+      ]
+    };
+
+    // set up DOM
+    document.body.innerHTML =
+      `<form method="post" action="${emailPageURL}" autocomplete="off" data-preview-type="email" novalidate>
+        <div class="grid-row"></div>
+        <div class="grid-row">
+          <div class="column-full">
+            <div data-module="autofocus">
+              <div class="live-search js-header" data-module="live-search" data-targets=".multiple-choice">
+                <div class="form-group">
+                  <label class="form-label" for="search">
+                      Search branding styles by name
+                  </label>
+                  <input autocomplete="off" class="form-control form-control-1-1 " id="search" name="search" required="" rows="8" type="search" value="">
+                </div>
+              </div>
+            </div> 
+          </div>
+        </div>
+        <div class="page-footer">
+          <button type="submit" class="button">Preview</button>
+        </div>
+      </form>`;
+
+    document.querySelector('.column-full').appendChild(helpers.getRadioGroup(brands));
+    form = document.querySelector('form');
+    radios = form.querySelector('fieldset');
+
+  });
+
+  afterEach(() => {
+
+    document.body.innerHTML = '';
+
+    // we run the previewPane.js script every test
+    // the module cache needs resetting each time for the script to execute
+    jest.resetModules();
+
+  });
+
+  describe("If the page type is 'email'", () => {
+
+    describe("When the page loads", () => {
+
+      test("it should add the preview pane", () => {
+
+        // run preview pane script
+        require('../../app/assets/javascripts/previewPane.js');
+
+        expect(document.querySelector('iframe')).not.toBeNull();
+
+      });
+
+      test("it should change the form to submit the selection instead of posting to a preview page", () => {
+
+        // run preview pane script
+        require('../../app/assets/javascripts/previewPane.js');
+
+        expect(form.getAttribute('action')).toEqual(emailPreviewConfirmationURL);
+
+      });
+
+      test("the preview pane should show the page for the selected brand", () => {
+
+        // run preview pane script
+        require('../../app/assets/javascripts/previewPane.js');
+
+        const selectedValue = Array.from(radios.querySelectorAll('input[type=radio]')).filter(radio => radio.checked)[0].value;
+
+        expect(document.querySelector('iframe').getAttribute('src')).toEqual(`/_email?branding_style=${selectedValue}`);
+
+      });
+
+      test("the submit button should change from 'Preview' to 'Save'", () => {
+
+        // run preview pane script
+        require('../../app/assets/javascripts/previewPane.js');
+
+        expect(document.querySelector('button[type=submit]').textContent).toEqual('Save');
+
+      });
+
+    });
+
+    describe("If the selection changes", () => {
+
+      test("the page shown should match the selected brand", () => {
+
+        // run preview pane script
+        require('../../app/assets/javascripts/previewPane.js');
+
+        const newSelection = radios.querySelectorAll('input[type=radio]')[1];
+
+        helpers.moveSelectionToRadio(newSelection);
+
+        expect(document.querySelector('iframe').getAttribute('src')).toEqual(`/_email?branding_style=${newSelection.value}`);
+
+      });
+
+    });
+
+  });
+
+  describe("If the page type is 'letter'", () => {
+
+    beforeEach(() => {
+
+      // set page URL and page type to 'letter'
+      window.location.pathname = letterPreviewConfirmationURL;
+      form.setAttribute('data-preview-type', 'letter');
+
+    });
+
+    describe("When the page loads", () => {
+
+      test("it should add the preview pane", () => {
+
+        // run preview pane script
+        require('../../app/assets/javascripts/previewPane.js');
+
+        expect(document.querySelector('iframe')).not.toBeNull();
+
+      });
+
+      test("it should change the form to submit the selection instead of posting to a preview page", () => {
+
+        // run preview pane script
+        require('../../app/assets/javascripts/previewPane.js');
+
+        expect(form.getAttribute('action')).toEqual(letterPreviewConfirmationURL);
+
+      });
+
+      test("the preview pane should show the page for the selected brand", () => {
+
+        // run preview pane script
+        require('../../app/assets/javascripts/previewPane.js');
+
+        const selectedValue = Array.from(radios.querySelectorAll('input[type=radio]')).filter(radio => radio.checked)[0].value;
+
+        expect(document.querySelector('iframe').getAttribute('src')).toEqual(`/_letter?branding_style=${selectedValue}`);
+
+      });
+
+      test("the submit button should change from 'Preview' to 'Save'", () => {
+
+        // run preview pane script
+        require('../../app/assets/javascripts/previewPane.js');
+
+        expect(document.querySelector('button[type=submit]').textContent).toEqual('Save');
+
+      });
+
+    });
+
+    describe("If the selection changes", () => {
+
+      test("the page shown should match the selected brand", () => {
+
+        // run preview pane script
+        require('../../app/assets/javascripts/previewPane.js');
+
+        const newSelection = radios.querySelectorAll('input[type=radio]')[1];
+
+        helpers.moveSelectionToRadio(newSelection);
+
+        expect(document.querySelector('iframe').getAttribute('src')).toEqual(`/_letter?branding_style=${newSelection.value}`);
+
+      });
+
+    });
+
+  });
+
+});
diff --git a/tests/javascripts/stick-to-window-when-scrolling.test.js b/tests/javascripts/stick-to-window-when-scrolling.test.js
index fec68663f..32bacaf9f 100644
--- a/tests/javascripts/stick-to-window-when-scrolling.test.js
+++ b/tests/javascripts/stick-to-window-when-scrolling.test.js
@@ -472,8 +472,8 @@ describe("Stick to top/bottom of window when scrolling", () => {
         // add another sticky element before the form footer
         radios = helpers.getRadioGroup({
           cssClasses: ['js-stick-at-top-when-scrolling'],
-          name: 'send-time',
-          label: 'send time',
+          name: 'choose-send-time',
+          label: 'Choose send time',
           fields: [
             {
               label: 'Now',
@@ -604,7 +604,7 @@ describe("Stick to top/bottom of window when scrolling", () => {
                 }
               });
 
-            radios.querySelector('fieldset').insertAdjacentHTML('beforeend', helpers.getRadios(fields));
+            radios.querySelector('fieldset').insertAdjacentHTML('beforeend', helpers.getRadios(fields, 'days'));
 
             radios.offsetHeight = 475;
 
@@ -1146,8 +1146,8 @@ describe("Stick to top/bottom of window when scrolling", () => {
         // add another sticky element before the form footer
         radios = helpers.getRadioGroup({
           cssClasses: ['js-stick-at-bottom-when-scrolling'],
-          name: 'send-time',
-          label: 'Send time',
+          name: 'choose-send-time',
+          label: 'Choose send time',
           fields: [
             {
               label: 'Now',
@@ -1280,7 +1280,7 @@ describe("Stick to top/bottom of window when scrolling", () => {
                 }
               });
 
-            radios.querySelector('fieldset').insertAdjacentHTML('beforeend', helpers.getRadios(fields));
+            radios.querySelector('fieldset').insertAdjacentHTML('beforeend', helpers.getRadios(fields, 'days'));
 
             radios.offsetHeight = 475;
 
diff --git a/tests/javascripts/support/helpers.js b/tests/javascripts/support/helpers.js
index 7fef27e98..90c253306 100644
--- a/tests/javascripts/support/helpers.js
+++ b/tests/javascripts/support/helpers.js
@@ -1,3 +1,4 @@
+const globals = require('./helpers/globals.js');
 const events = require('./helpers/events.js');
 const domInterfaces = require('./helpers/dom_interfaces.js');
 const html = require('./helpers/html.js');
@@ -6,6 +7,7 @@ const rendering = require('./helpers/rendering.js');
 const forms = require('./helpers/forms.js');
 const utilities = require('./helpers/utilities.js');
 
+exports.LocationMock = globals.LocationMock;
 exports.triggerEvent = events.triggerEvent;
 exports.clickElementWithMouse = events.clickElementWithMouse;
 exports.moveSelectionToRadio = events.moveSelectionToRadio;
diff --git a/tests/javascripts/support/helpers/globals.js b/tests/javascripts/support/helpers/globals.js
new file mode 100644
index 000000000..89fa44e08
--- /dev/null
+++ b/tests/javascripts/support/helpers/globals.js
@@ -0,0 +1,89 @@
+// helpers for mocking objects attached to the global space as properties, ie. window.location
+
+class LocationMock {
+
+  constructor (URL) {
+
+    this._location = window.location;
+
+    // setting href sets all sub-properties
+    this.href = URL;
+
+    // JSDOM sets window.location as non-configurable
+    // the only way to mock it, currently, is to replace it completely
+    delete window.location;
+    window.location = this;
+
+  }
+
+  get href () {
+
+    return `${this.protocol}://${this.host}${this.pathname}${this.search}${this.hash}`
+
+  }
+
+  set href (value) {
+
+    const partNames = ['protocol', 'hostname', 'port', 'pathname', 'search', 'hash'];
+
+    const protocol = '(https:|http:)';
+    const hostname = '[^\\/]+';
+    const port = '(:\\d)';
+    const pathname = '([^?]+)';
+    const search = '([^#])';
+    const hash = '(#[\\x00-\\x7F])'; // match any ASCII character
+
+    const re = new RegExp(`^${protocol}{0,1}(?:\\/\\/){0,1}(${hostname}${port}{0,1}){0,1}${pathname}{0,1}${search}{0,1}${hash}{0,1}$`);
+    const match = value.match(re)
+
+    if (match === null) { throw Error(`${value} is not a valid URL`); }
+
+    match.forEach((part, idx) => {
+
+      let partName;
+
+      // 0 index is whole match, we want the groups
+      if (idx > 0) {
+        partName = partNames[idx - 1];
+
+        if (part !== undefined) {
+          this[partName] = part;
+        } else if (!(partName in this)) { // only get value from window.location if property not set
+          this[partName] = this._location[partName];
+        }
+      }
+
+    });
+
+  }
+
+  get host () {
+
+    return `${this.hostname}:${this.port}`;
+
+  }
+
+  set host (value) {
+
+    const parts = value.split(':');
+
+    this.hostname = parts[0];
+    this.protocol = parts[1];
+
+  }
+
+  // origin is read-only
+  get origin () {
+
+    return `${this.protol}://${this.hostname}`;
+
+  }
+
+  reset () {
+
+    window.location = this._location;
+
+  }
+}
+
+exports.LocationMock = LocationMock;
diff --git a/tests/javascripts/support/helpers/html.js b/tests/javascripts/support/helpers/html.js
index 7b3d78eb4..e0b8aa22e 100644
--- a/tests/javascripts/support/helpers/html.js
+++ b/tests/javascripts/support/helpers/html.js
@@ -1,6 +1,6 @@
 // helpers for generating patterns of HTML
 
-function getRadios (fields) {
+function getRadios (fields, name) {
   const result = '';
 
   return fields.map((field, idx) => {
@@ -8,8 +8,8 @@ function getRadios (fields) {
 
     return `
       <div class="multiple-choice">
-        <input id="choose-${field.name}-1" name="choose-${field.name}-1" type="radio" value="${field.value}" ${field.checked ? 'checked' : ''}>
-        <label class="block-label" for="choose-${field.name}-1">
+        <input id="${name}-1" name="${name}" type="radio" value="${field.value}" ${field.checked ? 'checked' : ''}>
+        <label class="block-label" for="${name}-1">
           ${field.label}
         </label>
       </div>`;
@@ -22,11 +22,11 @@ function getRadioGroup (data) {
   data.cssClasses.forEach(cssClass => radioGroup.classList.add(cssClass));
   radioGroup.innerHTML = `
     <div class="form-group ">
-      <fieldset id="choose-${data.name}">
+      <fieldset id="${data.name}">
         <legend class="form-label">
-           Choose ${data.label}
+          ${data.label}
         </legend>
-        ${getRadios(data.fields)}
+        ${getRadios(data.fields, data.name)}
       </fieldset>
     </div>`;