151 fix: added agents unit tests

tests/unit/agents/test_agents.py

@@ -0,0 +1,126 @@
+"""Tests for fenn/agents/agent.py"""
+import pytest
+from unittest.mock import MagicMock, patch, mock_open
+
+
+FAKE_CONFIG = """
+agent:
+  system_prompt: "You are a helpful assistant."
+  max_iterations: 5
+"""
+
+
+def _make_agent():
+    """Construct an Agent with all heavy dependencies mocked out."""
+    mock_llm = MagicMock()
+
+    with patch("fenn.agents.agent.yaml.safe_load", return_value={
+        "agent": {"system_prompt": "You are helpful.", "max_iterations": 3}
+    }):
+        with patch("builtins.open", mock_open(read_data=FAKE_CONFIG)):
+            with patch("fenn.agents.agent.ThinkNode") as MockThink, \
+                 patch("fenn.agents.agent.ActNode") as MockAct, \
+                 patch("fenn.agents.agent.ObserveNode") as MockObserve, \
+                 patch("fenn.agents.agent.Flow") as MockFlow, \
+                 patch("fenn.agents.agent.get_tool_schema", return_value=[]):
+
+                # Make node - operator return the node itself so chaining doesn't error
+                for MockNode in (MockThink, MockAct, MockObserve):
+                    instance = MockNode.return_value
+                    instance.__sub__ = MagicMock(return_value=instance)
+                    instance.__rshift__ = MagicMock(return_value=instance)
+
+                from fenn.agents.agent import Agent
+                agent = Agent(config="fake_config.yaml", llm=mock_llm)
+
+    return agent, mock_llm, MockFlow
+
+
+# ── __init__ ───────────────────────────────────────────────────────────────────
+
+def test_agent_stores_llm():
+    agent, mock_llm, _ = _make_agent()
+    assert agent.llm is mock_llm
+
+
+def test_agent_loads_config():
+    agent, _, _ = _make_agent()
+    assert agent.config["agent"]["system_prompt"] == "You are helpful."
+    assert agent.config["agent"]["max_iterations"] == 3
+
+
+def test_agent_creates_flow():
+    agent, _, MockFlow = _make_agent()
+    assert agent.flow is MockFlow.return_value
+
+
+def test_agent_config_file_not_found():
+    from fenn.agents.agent import Agent
+    with pytest.raises((FileNotFoundError, OSError)):
+        Agent(config="/nonexistent/path/config.yaml", llm=MagicMock())
+
+
+# ── run ────────────────────────────────────────────────────────────────────────
+
+def test_run_calls_flow_run():
+    agent, _, _ = _make_agent()
+    agent.flow.run = MagicMock()
+
+    # Simulate flow.run appending a response message
+    def fake_run(shared):
+        shared["messages"].append({"role": "assistant", "content": "Done!"})
+
+    agent.flow.run.side_effect = fake_run
+
+    with patch("fenn.agents.agent.get_tool_schema", return_value=[]):
+        result = agent.run("Hello")
+
+    agent.flow.run.assert_called_once()
+    assert result == "Done!"
+
+
+def test_run_returns_last_message_content():
+    agent, _, _ = _make_agent()
+
+    def fake_run(shared):
+        shared["messages"].append({"role": "assistant", "content": "Final answer"})
+
+    agent.flow.run.side_effect = fake_run
+
+    result = agent.run("What is 2+2?")
+    assert result == "Final answer"
+
+
+def test_run_builds_correct_shared_state():
+    agent, mock_llm, _ = _make_agent()
+    captured = {}
+
+    def fake_run(shared):
+        captured.update(shared)
+        shared["messages"].append({"role": "assistant", "content": "ok"})
+
+    agent.flow.run.side_effect = fake_run
+
+    with patch("fenn.agents.agent.get_tool_schema", return_value=["tool1"]):
+        agent.run("Test input")
+
+    assert captured["llm"] is mock_llm
+    assert captured["messages"][0] == {"role": "system", "content": "You are helpful."}
+    assert captured["messages"][1] == {"role": "user", "content": "Test input"}
+    assert captured["tools"] == ["tool1"]
+    assert captured["iterations"] == 0
+    assert captured["max_iterations"] == 3
+    assert captured["last_thought"] is None
+    assert captured["last_observation"] is None
+
+
+def test_run_with_different_user_inputs():
+    agent, _, _ = _make_agent()
+
+    for user_input in ["Hello", "What time is it?", ""]:
+        def fake_run(shared):
+            shared["messages"].append({"role": "assistant", "content": "response"})
+
+        agent.flow.run.side_effect = fake_run
+        result = agent.run(user_input)
+        assert result == "response"