Add new data property to iframe that indicates if the content is ready.

Some tests fail because the iframe hasn't loaded the inner hedgedoc renderer yet
but cypress tries to travel through the dom and verify the render results.

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

cypress/support/getMarkdownRenderer.ts

@@ -14,7 +14,7 @@ declare namespace Cypress {
 
 Cypress.Commands.add('getMarkdownRenderer', () => {
   return cy
-    .get(`iframe[data-cy="documentIframe"]`)
+    .get(`iframe[data-cy="documentIframe"][data-content-ready="true"]`)
     .should('be.visible')
     .its('0.contentDocument')
     .should('exist')

src/components/editor-page/renderer-pane/render-iframe.tsx

@@ -140,6 +140,7 @@ export const RenderIframe: React.FC<RenderIframeProps> = ({
         {...(isTestMode() ? {} : { sandbox: 'allow-downloads allow-same-origin allow-scripts allow-popups' })}
         ref={frameReference}
         className={`border-0 ${frameClasses ?? ''}`}
+        data-content-ready={rendererReady}
       />
     </Fragment>
   )