Add further server setup tests splitting up configuration testing from CLI

tests/conftest.py

@@ -17,3 +17,11 @@ def mock_app(mocker):
     app = mocker.Mock()
     app.get.return_value = wrapper
     return app
+
+
+@pytest.fixture
+def mock_server(mock_app, mocker):
+    """Return a LabThings FastAPI server where .app is the mock_app fixture."""
+    server = mocker.Mock()
+    server.app = mock_app
+    return server

tests/test_server_cli.py

@@ -0,0 +1,102 @@
+"""Test server booting and shut down."""
+
+import logging
+
+import pytest
+from fastapi import FastAPI
+
+# Import as ofm server to attempt to minimise confusion with server as a var in other
+# functions and also FastAPI `Server`.
+from openflexure_microscope_server import server as ofm_server
+
+from .test_server_config import FULL_CONFIG
+
+
+def test_no_config():
+    """Check that an error is thrown if no configuration is set for the microspe via CLI."""
+    with pytest.raises(RuntimeError, match="No configuration"):
+        ofm_server.serve_from_cli([])
+
+
+def test_successful_start(mock_server, mocker, caplog):
+    """Check some basic things from the microscope setup.
+
+    This test checks that logging is set up and that the actual function used for
+    handling shutdown events shuts down the mjpeg streams.
+    """
+    # Create a mock for the camera so we can check the MJPEG streams are closed on
+    # shutdown.
+    mock_camera = mocker.Mock()
+    mock_server.things = {"/camera/": mock_camera}
+    # Mock the LabThings function that returns the server so we have a mock server
+    mocker.patch(
+        "openflexure_microscope_server.server.lt.cli.server_from_config",
+        return_value=mock_server,
+    )
+    # Also mock customisation or it will try to access the hard drive and make files.
+    mock_customise = mocker.patch.object(ofm_server, "customise_server")
+    # And mock uvicorn.run as we don't want to start a server process
+    mock_uvicorn_run = mocker.patch("openflexure_microscope_server.server.uvicorn.run")
+
+    # Run the mock CLI
+    ofm_server.serve_from_cli(["-c", FULL_CONFIG])
+
+    # Check that the server was customised and the run
+    assert mock_customise.call_count == 1
+    assert mock_uvicorn_run.call_count == 1
+    # Read the log config that was set
+    log_config = mock_uvicorn_run.call_args.kwargs["log_config"]
+    # Check both uvicorn loggers were set to propagate
+    assert log_config["loggers"]["uvicorn"]["propagate"]
+    assert log_config["loggers"]["uvicorn.access"]["propagate"]
+
+    # Now Mock a shutdown signal being sent
+    ofm_server.Server.handle_exit(mock_server.app, "mock_signal", "mock_frame")
+
+    # Check
+    assert mock_camera.kill_mjpeg_streams.call_count == 1
+
+    # Mock shutdown again but with the MJPEG stream throwing a BaseException
+    mock_camera.kill_mjpeg_streams.side_effect = BaseException("mock-54321")
+
+    # This should log at error level but even a BaseException will not cause an error
+    # that stops the shutdown signal propagating
+    with caplog.at_level(logging.ERROR):
+        ofm_server.Server.handle_exit(mock_server.app, "mock_signal", "mock_frame")
+    # Assert there is one error log
+    assert len(caplog.records) == 1
+    # And that it is the message raised by the kill_mjpeg_streams mock
+    assert str(caplog.records[0].msg) == "mock-54321"
+
+
+def test_failed_customise(mock_server, mocker):
+    """Check what happens if there is an error before the server is started by uvicorn.
+
+    This differs based on whether the --fallback flag is set.
+    """
+    # Mock the LabThings function that returns the server so we have a mock server
+    mocker.patch(
+        "openflexure_microscope_server.server.lt.cli.server_from_config",
+        return_value=mock_server,
+    )
+    # Also mock customisation or it will try to access the hard drive and make files.
+    mocker.patch.object(
+        ofm_server, "customise_server", side_effect=RuntimeError("Can't touch this")
+    )
+    # And mock uvicorn.run as we don't want to start a server process
+    mock_uvicorn_run = mocker.patch("openflexure_microscope_server.server.uvicorn.run")
+
+    # Running the mock CLI will error
+    with pytest.raises(RuntimeError, match="Can't touch this"):
+        ofm_server.serve_from_cli(["-c", FULL_CONFIG])
+
+    # But with the fallback flag uvicorn run will be run
+    ofm_server.serve_from_cli(["-c", FULL_CONFIG, "--fallback"])
+
+    assert mock_uvicorn_run.call_count == 1
+    # Get the fallback app passed to uvicorn tun
+    fallback_app = mock_uvicorn_run.call_args.args[0]
+    # Check it really is a fastapi
+    assert isinstance(fallback_app, FastAPI)
+    # An that it has the error to display
+    assert str(fallback_app.labthings_error) == "Can't touch this"

tests/test_server_config.py

@@ -6,7 +6,9 @@ from copy import deepcopy
 
 import pytest
 
-from openflexure_microscope_server import server
+# Import as ofm server to attempt to minimise confusion with server as a var in other
+# functions and also FastAPI `Server`.
+from openflexure_microscope_server import server as ofm_server
 
 THIS_DIR = os.path.dirname(os.path.abspath(__file__))
 REPO_ROOT = os.path.dirname(THIS_DIR)
@@ -20,16 +22,16 @@ def test_monkey_patched_handle_exit(side_effect, mock_app, mocker):
     # Setup the same for any side_effect
     # Create mocks for FastAPI.Server, and for our custom shutdown function
     mock_shutdown_func = mocker.Mock(side_effect=side_effect)
-    mock_fastapi_server = mocker.patch.object(server, "Server")
+    mock_fastapi_server = mocker.patch.object(ofm_server, "Server")
     original_mock_handle_exit = mock_fastapi_server.handle_exit
     handle_exit_args = (mock_app, "mock_signal", "mock_frame")
 
-    server.set_shutdown_function(mock_shutdown_func)
+    ofm_server.set_shutdown_function(mock_shutdown_func)
 
     if side_effect is None:
         # In normal operation, both the custom shutdown function and the original
         # handle_exit should be called
-        server.Server.handle_exit(*handle_exit_args)
+        ofm_server.Server.handle_exit(*handle_exit_args)
 
         assert mock_shutdown_func.call_count == 1
         assert original_mock_handle_exit.call_count == 1
@@ -39,30 +41,30 @@ def test_monkey_patched_handle_exit(side_effect, mock_app, mocker):
         # Use an error side effect to check that our custom shutdown function is called
         # before the standard `handle_exit`
         with pytest.raises(RuntimeError, match="Mock"):
-            server.Server.handle_exit(*handle_exit_args)
+            ofm_server.Server.handle_exit(*handle_exit_args)
         # The error was raised so we know our custom function was run, check that
-        # handle_exit wasn't
+        # handle_exit wasn't.
+        # Note: that the non-mocked shutdown function is entirely wrapped in a
+        # try/except BaseExcpetion, so that handle_exit will always run.
         assert original_mock_handle_exit.call_count == 0
 
 
-def test_customise_server(mock_app, mocker):
+def test_customise_server(mock_server, mocker):
     """Check that all server customisation stages are called."""
     # Mock everything to be called in customisation, partly setup may not be complete,
     # but also to limit excess coverage reporting.
-    mocked_add_static = mocker.patch.object(server, "add_static_files")
-    mocked_v2_endpoints = mocker.patch.object(server, "add_v2_endpoints")
-    mocked_configure_logging = mocker.patch.object(server, "configure_logging")
-    mocked_retrieve_log = mocker.patch.object(server, "retrieve_log")
-    mocked_retrieve_log_file = mocker.patch.object(server, "retrieve_log_from_file")
+    mocked_add_static = mocker.patch.object(ofm_server, "add_static_files")
+    mocked_v2_endpoints = mocker.patch.object(ofm_server, "add_v2_endpoints")
+    mocked_configure_logging = mocker.patch.object(ofm_server, "configure_logging")
+    mocked_retrieve_log = mocker.patch.object(ofm_server, "retrieve_log")
+    mocked_retrieve_log_file = mocker.patch.object(ofm_server, "retrieve_log_from_file")
 
-    # Set up a mock server
-    mock_server = mocker.Mock()
-    mock_server.app = mock_app
+    mock_app = mock_server.app
     # The wrapper returned for app.get so we can see what functions are decorated.
     wrapper = mock_app.get.return_value
 
     # Finally we can run it!
-    server.customise_server(mock_server, "mock_log_folder", "mock_scan_folder")
+    ofm_server.customise_server(mock_server, "mock_log_folder", "mock_scan_folder")
 
     # Check each internal customisation function is called
     assert mocked_add_static.call_count == 1
@@ -89,7 +91,7 @@ def test_get_scans_dir_ok(config_file, expected_scan_dir):
     """Test the _get_scans_dir function and also check the standard config files."""
     with open(config_file, "r", encoding="utf-8") as f_obj:
         config_dict = json.load(f_obj)
-    assert server._get_scans_dir(config_dict) == expected_scan_dir
+    assert ofm_server._get_scans_dir(config_dict) == expected_scan_dir
 
 
 def test_get_scans_dir_no_smart_scan():
@@ -100,7 +102,7 @@ def test_get_scans_dir_no_smart_scan():
     # Delete smart scan
     del config_dict["things"]["/smart_scan/"]
     # No SmartScanThing, should return None
-    assert server._get_scans_dir(config_dict) is None
+    assert ofm_server._get_scans_dir(config_dict) is None
 
 
 def test_get_scans_dir_bad_smart_scan_config():
@@ -115,11 +117,11 @@ def test_get_scans_dir_bad_smart_scan_config():
     del broken_config["things"]["/smart_scan/"]["kwargs"]
     # Creates an Error
     with pytest.raises(RuntimeError):
-        server._get_scans_dir(broken_config)
+        ofm_server._get_scans_dir(broken_config)
 
     # Same thing should happen if just the scans_folder key is deleted
     broken_config = deepcopy(config_dict)
     del broken_config["things"]["/smart_scan/"]["kwargs"]
     # Creates an Error
     with pytest.raises(RuntimeError):
-        server._get_scans_dir(broken_config)
+        ofm_server._get_scans_dir(broken_config)