add depth-utils.spec.ts

packages/remark-lsx/src/utils/depth-utils.spec.ts

@@ -0,0 +1,13 @@
+import { getDepthOfPath } from './depth-utils';
+
+describe('getDepthOfPath()', () => {
+
+  it('returns 0 when the path does not include slash', () => {
+    // when
+    const result = getDepthOfPath('Sandbox');
+
+    // then
+    expect(result).toBe(0);
+  });
+
+});