chore: import upstream snapshot with attribution

tools/challenge-helper-scripts/helpers/insert-erms.test.ts

@@ -0,0 +1,50 @@
+import { describe, it, expect } from 'vitest';
+import { insertErms } from './insert-erms.js';
+
+describe('insertErms helper', () => {
+  const code = `<h1>Hello World</h1>
+<main>
+<h2>CatPhotoApp</h2>
+<img src="https://www.bit.ly/fcc-relaxing-cat" alt="A cute orange cat lying on its back.">
+<p>Kitty ipsum dolor sit amet, shed everywhere shed everywhere stretching attack your ankles chase the red dot, hairball run catnip eat the grass sniff.</p>
+<p>Purr jump eat the grass rip the couch scratched sunbathe, shed everywhere rip the couch sleep in the sink fluffy fur catnip scratched.</p>
+</main>`;
+
+  it('should throw error if erm length is less than 2', () => {
+    const items = [[], [1]];
+
+    items.forEach(item => {
+      expect(() => {
+        insertErms(code, item);
+      }).toThrow();
+    });
+  });
+
+  it('should update code with markers if provided', () => {
+    const newCode = `--fcc-editable-region--
+<h1>Hello World</h1>
+<main>
+<h2>CatPhotoApp</h2>
+<img src="https://www.bit.ly/fcc-relaxing-cat" alt="A cute orange cat lying on its back.">
+<p>Kitty ipsum dolor sit amet, shed everywhere shed everywhere stretching attack your ankles chase the red dot, hairball run catnip eat the grass sniff.</p>
+<p>Purr jump eat the grass rip the couch scratched sunbathe, shed everywhere rip the couch sleep in the sink fluffy fur catnip scratched.</p>
+--fcc-editable-region--
+</main>`;
+
+    expect(insertErms(code, [0, 7])).toEqual(newCode);
+  });
+
+  it('should update code with 2 markers if more are provided', () => {
+    const newCode = `<h1>Hello World</h1>
+<main>
+--fcc-editable-region--
+<h2>CatPhotoApp</h2>
+--fcc-editable-region--
+<img src="https://www.bit.ly/fcc-relaxing-cat" alt="A cute orange cat lying on its back.">
+<p>Kitty ipsum dolor sit amet, shed everywhere shed everywhere stretching attack your ankles chase the red dot, hairball run catnip eat the grass sniff.</p>
+<p>Purr jump eat the grass rip the couch scratched sunbathe, shed everywhere rip the couch sleep in the sink fluffy fur catnip scratched.</p>
+</main>`;
+
+    expect(insertErms(code, [2, 4, 6, 7])).toEqual(newCode);
+  });
+});