chore:add e2e test

on-behalf-of: @Mermaid-Chart <hello@mermaidchart.com>

cypress/helpers/util.ts

@@ -97,10 +97,18 @@ export const openURLAndVerifyRendering = (
 
   cy.visit(url);
   cy.window().should('have.property', 'rendered', true);
-  cy.get('svg').should('be.visible');
 
-  if (validation) {
+  // Handle sandbox mode where SVG is inside an iframe
-    cy.get('svg').should(validation);
+  if (options.securityLevel === 'sandbox') {
+    cy.get('iframe').should('be.visible');
+    if (validation) {
+      cy.get('iframe').should(validation);
+    }
+  } else {
+    cy.get('svg').should('be.visible');
+    if (validation) {
+      cy.get('svg').should(validation);
+    }
   }
 
   verifyScreenshot(name);

cypress/integration/rendering/flowchart-v2.spec.js

@@ -79,6 +79,18 @@ describe('Flowchart v2', () => {
       { htmlLabels: true, flowchart: { htmlLabels: true }, securityLevel: 'loose' }
     );
   });
+  it('6a: should render complex HTML in labels with sandbox security', () => {
+    imgSnapshotTest(
+      `flowchart TD
+    A[Christmas] -->|Get money| B(Go shopping)
+    B --> C{Let me think}
+    C -->|One| D[Laptop]
+    C -->|Two| E[iPhone]
+    C -->|Three| F[fa:fa-car Car]
+      `,
+      { securityLevel: 'sandbox', flowchart: { htmlLabels: true } }
+    );
+  });
   it('7: should render a flowchart when useMaxWidth is true (default)', () => {
     renderGraph(
       `flowchart TD