MC-23058: Template strict mode is not set for unsaved template previews

Author: nathanjosiah

app/code/Magento/Newsletter/Test/Mftf/ActionGroup/AdminNewsletterTemplateActionGroup.xml

@@ -31,19 +31,25 @@
     </actionGroup>
 
     <actionGroup name="OpenNewsletterPreviewTab">
-        <waitForElementVisible selector="{{BasicFieldNewsletterSection.templateName}}" stepKey="waitForPreviewButton"/>
+        <annotations>
+            <description>Open the currently drafted newletter in new tab preview mode. The JS is required due to the sandboxed iframe not playing nicely with selenium.</description>
+        </annotations>
+        <waitForElementVisible selector="{{BasicFieldNewsletterSection.preview}}" stepKey="waitForPreviewButton"/>
         <click selector="{{BasicFieldNewsletterSection.preview}}" stepKey="clickPreview"/>
         <switchToNextTab stepKey="switchToPreviewTab"/>
         <waitForPageLoad stepKey="waitForTabLoaded"/>
         <waitForElementVisible selector="{{BasicFieldNewsletterSection.previewIframe}}" stepKey="waitForIframeVisible"/>
-        <waitForJS function="return document.getElementById('preview_iframe').sandbox.add('allow-scripts') || true" stepKey="removeSandboxValues"/>
+        <waitForJS function="return document.getElementById('preview_iframe').sandbox.add('allow-scripts') || true" stepKey="addSandboxValue"/>
     </actionGroup>
 
     <actionGroup name="AssertNewsletterContent">
+        <annotations>
+            <description>Validate the content of the newsletter preview tab that is open. JS is used due to strange behaviors with selenium and the posted form sandboxed iframe containing the text.</description>
+        </annotations>
         <arguments>
             <argument name="Newsletter" defaultValue="BasicFieldNewsletterSection"/>
         </arguments>
-        <executeJS function="return document.getElementById('preview_iframe').contentDocument.body.textContent" stepKey="grabTemplateText"/>
+        <waitForJS function="return document.getElementById('preview_iframe').contentDocument.body.textContent" stepKey="grabTemplateText"/>
         <assertContains stepKey="checkTemplateContainsText">
             <actualResult type="variable">grabTemplateText</actualResult>
             <expectedResult type="string">{{Newsletter.expectedTemplate}}</expectedResult>