feat(content): function signatures + test cases

backend/data/questions/buddy-strings.yaml

@@ -9,6 +9,30 @@ categories:
 patterns:
   - two-pointers
 
+function_signature: "def buddy_strings(s: str, goal: str) -> bool:"
+
+test_cases:
+  visible:
+    - input: { s: "ab", goal: "ba" }
+      expected: true
+    - input: { s: "ab", goal: "ab" }
+      expected: false
+    - input: { s: "aa", goal: "aa" }
+      expected: true
+  hidden:
+    - input: { s: "aaaaaaabc", goal: "aaaaaaacb" }
+      expected: true
+    - input: { s: "abcd", goal: "badc" }
+      expected: false
+    - input: { s: "a", goal: "a" }
+      expected: false
+    - input: { s: "ab", goal: "ca" }
+      expected: false
+    - input: { s: "abab", goal: "abab" }
+      expected: true
+    - input: { s: "abcdef", goal: "abcfed" }
+      expected: false
+
 description: |
   Given two strings `s` and `goal`, return `true` *if you can swap two letters in* `s` *so the result is equal to* `goal`, *otherwise, return* `false`.