Implementiere Feature1

feature1.py

+from abc import ABC, abstractmethod
+import unittest
+
+class IStringCalculator(ABC):
+    @abstractmethod
+    def add(self, numbers: str) -> int:
+        pass
+
+class StringCalculator(IStringCalculator):
+    def add(self, numbers: str) -> int:
+        if not numbers:
+            return 0
+        return sum(map(int, numbers.split(',')))
+
+class TestStringCalculator(unittest.TestCase):
+    def setUp(self):
+        self.calculator = StringCalculator()
+    
+    def test_empty_string(self):
+        self.assertEqual(self.calculator.add(""), 0)
+    
+    def test_single_number(self):
+        self.assertEqual(self.calculator.add("1"), 1)
+    
+    def test_two_numbers(self):
+        self.assertEqual(self.calculator.add("1,2"), 3)
+    
+    def test_multiple_numbers(self):
+        self.assertEqual(self.calculator.add("1,2,3,4,5"), 15)
+
+if __name__ == "__main__":
+    unittest.main()