[server]: Add return_punctuality_by_timestamp unit tests

server/src/test/return_punctuality_by_timestamp/test_return_punctuality_by_timestamp.py

@@ -0,0 +1,92 @@
+import unittest
+from unittest.mock import patch, MagicMock
+import json
+from functions.return_punctuality_by_timestamp.lambda_function import lambda_handler
+
+class TestPunctualityLambda(unittest.TestCase):
+    """
+    Unit tests for the Lambda function that retrieves punctuality data by timestamp.
+    """
+
+    @patch("functions.return_punctuality_by_timestamp.lambda_function.dynamodb.Table")
+    def test_lambda_handler_success(self, mock_table):
+        """
+        Test Lambda function when DynamoDB returns valid data.
+        """
+        mock_table.return_value.scan.return_value = {
+            "Items": [
+                {"timestamp": "1711814400", "average_punctuality": "95"},
+                {"timestamp": "1711900800", "average_punctuality": "88"}
+            ]
+        }
+
+        event = {}
+        result = lambda_handler(event, {})
+
+        self.assertEqual(result["statusCode"], 200)
+        body = json.loads(result["body"])
+        self.assertIsInstance(body, list)
+        self.assertEqual(len(body), 2)  # Expecting 2 items
+        self.assertEqual(body[0]["timestamp"], "1711814400")
+        self.assertEqual(body[1]["average_punctuality"], "88")
+
+    @patch("functions.return_punctuality_by_timestamp.lambda_function.dynamodb.Table")
+    def test_lambda_handler_empty_response(self, mock_table):
+        """
+        Test Lambda function when DynamoDB returns an empty response.
+        """
+        mock_table.return_value.scan.return_value = {"Items": []}  # Empty dataset
+
+        event = {}
+        result = lambda_handler(event, {})
+
+        self.assertEqual(result["statusCode"], 200)
+        body = json.loads(result["body"])
+        self.assertIsInstance(body, list)
+        self.assertEqual(len(body), 0)  # Expecting an empty list
+
+    @patch("functions.return_punctuality_by_timestamp.lambda_function.dynamodb.Table")
+    def test_lambda_handler_pagination(self, mock_table):
+        """
+        Test Lambda function handles paginated DynamoDB results correctly.
+        """
+        # Simulate paginated responses
+        def scan_side_effect(*args, **kwargs):
+            if "ExclusiveStartKey" not in kwargs:
+                return {"Items": [{"timestamp": "1711814400", "average_punctuality": "95"}], "LastEvaluatedKey": "key1"}
+            elif kwargs["ExclusiveStartKey"] == "key1":
+                return {"Items": [{"timestamp": "1711900800", "average_punctuality": "88"}], "LastEvaluatedKey": "key2"}
+            elif kwargs["ExclusiveStartKey"] == "key2":
+                return {"Items": [{"timestamp": "1711987200", "average_punctuality": "92"}]}  # Last page
+
+        mock_table.return_value.scan.side_effect = scan_side_effect
+
+        event = {}
+        result = lambda_handler(event, {})
+
+        self.assertEqual(result["statusCode"], 200)
+        body = json.loads(result["body"])
+        self.assertIsInstance(body, list)
+        self.assertEqual(len(body), 3)  # Expecting 3 items
+        self.assertEqual(body[0]["timestamp"], "1711814400")
+        self.assertEqual(body[1]["timestamp"], "1711900800")
+        self.assertEqual(body[2]["timestamp"], "1711987200")
+
+    @patch("functions.return_punctuality_by_timestamp.lambda_function.dynamodb.Table")
+    def test_lambda_handler_exception(self, mock_table):
+        """
+        Test Lambda function when an exception occurs (e.g., DynamoDB error).
+        """
+        mock_table.return_value.scan.side_effect = Exception("DynamoDB error")  # Simulate error
+
+        event = {}
+        result = lambda_handler(event, {})
+
+        self.assertEqual(result["statusCode"], 500)
+        body = json.loads(result["body"])
+        self.assertIsInstance(body, dict)
+        self.assertIn("error", body)
+        self.assertEqual(body["error"], "DynamoDB error")
+
+if __name__ == "__main__":
+    unittest.main()