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/agents/test_agent_creator.py

@@ -0,0 +1,56 @@
+import pytest
+from application.agents.agent_creator import AgentCreator
+from application.agents.classic_agent import ClassicAgent
+from application.agents.react_agent import ReActAgent
+
+
+@pytest.mark.unit
+class TestAgentCreator:
+
+    def test_create_classic_agent(self, agent_base_params):
+        agent = AgentCreator.create_agent("classic", **agent_base_params)
+        assert isinstance(agent, ClassicAgent)
+        assert agent.endpoint == agent_base_params["endpoint"]
+        assert agent.llm_name == agent_base_params["llm_name"]
+        assert agent.gpt_model == agent_base_params["gpt_model"]
+
+    def test_create_react_agent(self, agent_base_params):
+        agent = AgentCreator.create_agent("react", **agent_base_params)
+        assert isinstance(agent, ReActAgent)
+        assert agent.endpoint == agent_base_params["endpoint"]
+        assert agent.llm_name == agent_base_params["llm_name"]
+
+    def test_create_agent_case_insensitive(self, agent_base_params):
+        agent_upper = AgentCreator.create_agent("CLASSIC", **agent_base_params)
+        agent_mixed = AgentCreator.create_agent("ClAsSiC", **agent_base_params)
+
+        assert isinstance(agent_upper, ClassicAgent)
+        assert isinstance(agent_mixed, ClassicAgent)
+
+    def test_create_agent_invalid_type(self, agent_base_params):
+        with pytest.raises(ValueError, match="No agent class found for type"):
+            AgentCreator.create_agent("invalid_agent_type", **agent_base_params)
+
+    def test_agent_registry_contains_expected_agents(self):
+        assert "classic" in AgentCreator.agents
+        assert "react" in AgentCreator.agents
+        assert AgentCreator.agents["classic"] == ClassicAgent
+        assert AgentCreator.agents["react"] == ReActAgent
+
+    def test_create_agent_with_optional_params(self, agent_base_params):
+        agent_base_params["user_api_key"] = "user_key_123"
+        agent_base_params["chat_history"] = [{"prompt": "test", "response": "test"}]
+        agent_base_params["json_schema"] = {"type": "object"}
+
+        agent = AgentCreator.create_agent("classic", **agent_base_params)
+
+        assert agent.user_api_key == "user_key_123"
+        assert len(agent.chat_history) == 1
+        assert agent.json_schema == {"type": "object"}
+
+    def test_create_agent_with_attachments(self, agent_base_params):
+        attachments = [{"name": "file.txt", "content": "test"}]
+        agent_base_params["attachments"] = attachments
+
+        agent = AgentCreator.create_agent("classic", **agent_base_params)
+        assert agent.attachments == attachments