feat(content): hidden test cases

backend/data/questions/subtree-of-another-tree.yaml

@@ -27,6 +27,12 @@ test_cases:
       expected: true
     - input: { root: [1, 2, 3], sub_root: [3, 1] }
       expected: false
+    - input: { root: [3, 4, 5, 1, null, 2], sub_root: [3, 1, 2] }
+      expected: false
+    - input: { root: [1, 2, 3, 4, 5], sub_root: [2, 4, 5] }
+      expected: true
+    - input: { root: [1], sub_root: [0] }
+      expected: false
 
 description: |
   Given the roots of two binary trees `root` and `subRoot`, return `true` if there is a subtree of `root` with the same structure and node values of `subRoot` and `false` otherwise.