Add an integration test with streamlit app

tests/integration/test_docker_e2e.py

@@ -1,4 +1,5 @@
 import pytest
+from streamlit.testing.v1 import AppTest
 
 from client import AgentClient
 
@@ -13,3 +14,24 @@ def test_service_with_fake_model():
     response = client.invoke("Tell me a joke?", model="fake")
     assert response.type == "ai"
     assert response.content == "This is a test response from the fake model."
+
+
+@pytest.mark.docker
+def test_service_with_app():
+    """Test the service using the app.
+
+    This test requires the service container to be running with USE_FAKE_MODEL=true
+    """
+    at = AppTest.from_file("../../src/streamlit_app.py").run()
+    assert at.chat_message[0].avatar == "assistant"
+    welcome = at.chat_message[0].markdown[0].value
+    assert welcome.startswith("Hello! I'm an AI-powered research assistant")
+    assert not at.exception
+
+    at.sidebar.selectbox[1].set_value("chatbot")
+    at.chat_input[0].set_value("What is the weather in Tokyo?").run()
+    assert at.chat_message[0].avatar == "user"
+    assert at.chat_message[0].markdown[0].value == "What is the weather in Tokyo?"
+    assert at.chat_message[1].avatar == "assistant"
+    assert at.chat_message[1].markdown[0].value == "This is a test response from the fake model."
+    assert not at.exception