Add test

cypress/integration/layout.spec.ts

@@ -0,0 +1,29 @@
+describe('Graph layout', () => {
+  it('layout should not fail with self transitions on machine node', () => {
+    // Plant a fake entry in localStorage
+    cy.setLocalStorage(
+      'xstate_viz_raw_source|no_source',
+      JSON.stringify({
+        date: new Date(),
+        sourceRawContent: `
+import { createMachine } from 'xstate';
+const machine = createMachine({
+  on: {
+    // These will now display as expected
+    LOAD: {},
+    UPDATE: {},
+  },
+  states: {
+    something: {},
+  },
+});
+`,
+      }),
+    );
+
+    cy.visit('/viz');
+
+    // Will time out if visualization fails
+    cy.getCanvas();
+  });
+});