chore: add unit test for router and implement command router

ref: N25B-205

test/unit/api/endpoints/test_command_endpoint.py

@@ -0,0 +1,62 @@
+import pytest
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+from unittest.mock import MagicMock
+
+from control_backend.api.v1.endpoints import command
+from control_backend.schemas.ri_message import SpeechCommand
+
+@pytest.fixture
+def app():
+    """
+    Creates a FastAPI test app and attaches the router under test.
+    Also sets up a mock internal_comm_socket.
+    """
+    app = FastAPI()
+    app.include_router(command.router)
+    app.state.internal_comm_socket = MagicMock()  # mock ZMQ socket
+    return app
+
+
+@pytest.fixture
+def client(app):
+    """Create a test client for the app."""
+    return TestClient(app)
+
+
+def test_receive_command_endpoint(client, app):
+    """
+    Test that a POST to /command sends the right multipart message
+    and returns a 202 with the expected JSON body.
+    """
+    mock_socket = app.state.internal_comm_socket
+
+    # Prepare test payload that matches SpeechCommand
+    payload = {"endpoint": "actuate/speech", "data": "yooo"}
+
+    # Send POST request
+    response = client.post("/command", json=payload)
+
+    # Check response
+    assert response.status_code == 202
+    assert response.json() == {"status": "Command received"}
+
+    # Verify that the socket was called with the correct data
+    assert mock_socket.send_multipart.called, "Socket should be used to send data"
+
+    args, kwargs = mock_socket.send_multipart.call_args
+    sent_data = args[0]
+
+    assert sent_data[0] == b"command"
+    # Check JSON encoding roughly matches
+    assert isinstance(sent_data[1], SpeechCommand)
+
+
+def test_receive_command_invalid_payload(client):
+    """
+    Test invalid data handling (schema validation).
+    """
+    # Missing required field(s)
+    bad_payload = {"invalid": "data"}
+    response = client.post("/command", json=bad_payload)
+    assert response.status_code == 422  # validation error