feat(content): hidden test cases

backend/data/questions/check-knight-tour-configuration.yaml

@@ -9,6 +9,22 @@ categories:
 patterns:
   - matrix-traversal
 
+function_signature: "def check_valid_grid(grid: list[list[int]]) -> bool:"
+
+test_cases:
+  visible:
+    - input: { grid: [[0, 11, 16, 5, 20], [17, 4, 19, 10, 15], [12, 1, 8, 21, 6], [3, 18, 23, 14, 9], [24, 13, 2, 7, 22]] }
+      expected: true
+    - input: { grid: [[0, 3, 6], [5, 8, 1], [2, 7, 4]] }
+      expected: false
+  hidden:
+    - input: { grid: [[0, 2, 4], [5, 7, 1], [6, 3, 8]] }
+      expected: false
+    - input: { grid: [[1, 0, 2], [3, 4, 5], [6, 7, 8]] }
+      expected: false
+    - input: { grid: [[0, 5, 4], [3, 2, 7], [6, 1, 8]] }
+      expected: false
+
 description: |
   There is a knight on an `n x n` chessboard. In a valid configuration, the knight starts **at the top-left cell** of the board and visits every cell on the board **exactly once**.