Update backtest service functionality and corresponding unit tests A…

…ddresses issue #28

app/services/backtest_service.py

@@ -0,0 +1,9 @@
+import sys
+import os
+sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), '..', '..')))
+from scripts.backtest_runner import run_backtest, RsiBollingerBandsStrategy
+
+class BacktestService:
+    @staticmethod
+    def execute_backtest(symbol, start_date, end_date):
+        return run_backtest(RsiBollingerBandsStrategy, symbol, start_date, end_date)

tests/unit/test_backtest_service.py

@@ -0,0 +1,10 @@
+import unittest
+from app.services.backtest_service import BacktestService
+
+class TestBacktestService(unittest.TestCase):
+    def test_execute_backtest(self):
+        result = BacktestService.execute_backtest('BTC/USDT', '2023-06-20', '2024-06-20')
+        self.assertIn('Ending Portfolio Value', result)
+
+if __name__ == '__main__':
+    unittest.main()