Add acceptance test for form preview

[MAILPOET-2743]

assets/js/src/common/preview/preview.jsx

@@ -26,6 +26,7 @@ function Preview({
           }}
           title={MailPoet.I18n.t('formPreviewDesktop')}
           href="#"
+          data-automation-id="preview_type_desktop"
         >
           <DesktopIcon />
         </a>
@@ -37,6 +38,7 @@ function Preview({
           }}
           title={MailPoet.I18n.t('formPreviewMobile')}
           href="#"
+          data-automation-id="preview_type_mobile"
         >
           <MobileIcon />
         </a>

assets/js/src/form_editor/components/header.jsx

@@ -28,6 +28,7 @@ export default () => {
           onClick={showPreview}
           isPressed={isPreview}
           className="editor-post-preview"
+          data-automation-id="form_preview_button"
         >
           {__('Preview')}
         </Button>

assets/js/src/form_editor/components/preview.jsx

@@ -132,6 +132,7 @@ const FormPreview = () => {
               <select
                 onChange={onChange(setFormType)}
                 value={formType}
+                data-automation-id="form_type_selection"
               >
                 <option value="sidebar">{MailPoet.I18n.t('placeFormSidebar')}</option>
                 <option value="below_post">{MailPoet.I18n.t('placeFormBellowPages')}</option>
@@ -155,6 +156,7 @@ const FormPreview = () => {
               src={iframeSrc}
               title={MailPoet.I18n.t('formPreview')}
               onLoad={() => setIframeLoaded(true)}
+              data-automation-id="form_preview_iframe"
             />
           </Preview>
         </>