feat(content): function signatures + test cases

backend/data/questions/binary-gap.yaml

@@ -8,6 +8,30 @@ categories:
 patterns:
   - two-pointers
 
+function_signature: "def binary_gap(n: int) -> int:"
+
+test_cases:
+  visible:
+    - input: { n: 22 }
+      expected: 2
+    - input: { n: 8 }
+      expected: 0
+    - input: { n: 5 }
+      expected: 2
+  hidden:
+    - input: { n: 1 }
+      expected: 0
+    - input: { n: 6 }
+      expected: 1
+    - input: { n: 9 }
+      expected: 3
+    - input: { n: 15 }
+      expected: 1
+    - input: { n: 17 }
+      expected: 4
+    - input: { n: 1073741824 }
+      expected: 0
+
 description: |
   Given a positive integer `n`, find and return *the **longest distance** between any two **adjacent*** `1`*'s in the binary representation of* `n`. If there are no two adjacent `1`'s, return `0`.