feat(content): function signatures + test cases

backend/data/questions/arithmetic-slices.yaml

@@ -9,6 +9,26 @@ categories:
 patterns:
   - dynamic-programming
 
+function_signature: "def number_of_arithmetic_slices(nums: list[int]) -> int:"
+
+test_cases:
+  visible:
+    - input: { nums: [1, 2, 3, 4] }
+      expected: 3
+    - input: { nums: [1] }
+      expected: 0
+  hidden:
+    - input: { nums: [1, 2] }
+      expected: 0
+    - input: { nums: [1, 2, 3] }
+      expected: 1
+    - input: { nums: [1, 2, 3, 4, 5] }
+      expected: 6
+    - input: { nums: [7, 7, 7, 7] }
+      expected: 3
+    - input: { nums: [1, 2, 3, 5, 7] }
+      expected: 1
+
 description: |
   An integer array is called *arithmetic* if it consists of **at least three elements** and if the difference between any two consecutive elements is the same.