test: add agent test coverage and standardize test suite (#2051)

- Add 104 comprehensive tests for agent system
- Integrate agent tests into CI/CD pipeline
- Standardize tests with @pytest.mark.unit markers
- Fix cross-platform path compatibility
- Clean up unused imports and dependencies

tests/test_error.py

@@ -1,6 +1,6 @@
 import pytest
-from flask import Flask
 from application.error import bad_request, response_error
+from flask import Flask
 
 
 @pytest.fixture
@@ -9,31 +9,35 @@ def app():
     return app
 
 
+@pytest.mark.unit
 def test_bad_request_with_message(app):
     with app.app_context():
         message = "Invalid input"
         response = bad_request(status_code=400, message=message)
         assert response.status_code == 400
-        assert response.json == {'error': 'Bad Request', 'message': message}
+        assert response.json == {"error": "Bad Request", "message": message}
 
 
+@pytest.mark.unit
 def test_bad_request_without_message(app):
     with app.app_context():
         response = bad_request(status_code=400)
         assert response.status_code == 400
-        assert response.json == {'error': 'Bad Request'}
+        assert response.json == {"error": "Bad Request"}
 
 
+@pytest.mark.unit
 def test_response_error_with_message(app):
     with app.app_context():
         message = "Something went wrong"
         response = response_error(code_status=500, message=message)
         assert response.status_code == 500
-        assert response.json == {'error': 'Internal Server Error', 'message': message}
+        assert response.json == {"error": "Internal Server Error", "message": message}
 
 
+@pytest.mark.unit
 def test_response_error_without_message(app):
     with app.app_context():
         response = response_error(code_status=500)
         assert response.status_code == 500
-        assert response.json == {'error': 'Internal Server Error'}
+        assert response.json == {"error": "Internal Server Error"}