             // keeping all existing JS in place.
             webVC?.wkUserContentControllerTestingConfigurationBlock = { userContentController in
                 // Add self as 'jsTesting' script message handler.
-                userContentController.add(self, name: self.jsTestingMessageHandlerString)
+                userContentController.add(self, name: self.testFirstSectionAppearanceMessageHandlerString)
                 
                 // This message will be sent as soon as the web view inflates the DOM of the index.html (before our
                 // sections are injected).
-                let startTimeJS = "window.webkit.messageHandlers.\(self.jsTestingMessageHandlerString).postMessage('\(self.startTimeMessageString)')"
+                let startTimeJS = "window.webkit.messageHandlers.\(self.testFirstSectionAppearanceMessageHandlerString).postMessage('\(self.testFirstSectionAppearanceStartTimeMessageString)')"
                 userContentController.addUserScript(
                     WKUserScript.init(source: startTimeJS, injectionTime: .atDocumentEnd, forMainFrameOnly: true)
                 )

        }
        
        switch message.name {
        case jsTestingMessageHandlerString:
            switch messageString {
            case startTimeMessageString:
                startTimeMessageReceivedExpectation?.fulfill()
            case firstSectionAppearedMessageString:
                firstSectionAppearedMessageReceivedExpectation?.fulfill()
            default:
                return

                let tenMillisecondPollingJS = """
                const checkFirstSectionPresence = () => {
                   if(document.querySelector('#section_heading_and_content_block_0')){
                       window.webkit.messageHandlers.\(self.testFirstSectionAppearanceMessageHandlerString).postMessage('\(self.testFirstSectionAppearedMessageString)')
                   }else{
                       setTimeout(checkFirstSectionPresence, 10 )
                   }
