Add webservice.parse_config test

tests/test_webservice.py

@@ -4,7 +4,7 @@ from pathlib import Path
 import pytest
 
 sys.path.insert(0, Path(__file__).parent / 'webservice')
-from webservice.webservice import check_files, merge  # noqa
+from webservice.webservice import check_files, merge, parse_config  # noqa
 
 
 def test_check_files():
@@ -36,3 +36,30 @@ def test_merge():
                                  'number': 1}},
                 'completely': 'different'}
     assert ret == expected
+
+
+def test_parse_config():
+    cmd = ['whatever']
+    config = {'somebool': True,
+              'notsomebool': False,
+              'alist': [1, 2, 3],
+              'some_empty_key': '""',
+              'other_empty_key': "''",
+              'brian': 'scone'}
+
+    expected = ['whatever', '--somebool', '--alist', '1', '2', '3',
+                '--some_empty_key', '', '--other_empty_key', '',
+                '--brian', 'scone']
+
+    config = parse_config(cmd, config)
+
+    assert config == expected
+    assert '--notsomebool' not in config
+
+    with pytest.raises(ValueError):
+        config = {'some key': 'value'}
+        config = parse_config(cmd, config)
+
+    with pytest.raises(ValueError):
+        config = {'somekey': 'a value'}
+        config = parse_config(cmd, config)

webservice/webservice.py

@@ -13,7 +13,7 @@ import urllib.parse
 from asyncio import get_event_loop, shield
 from datetime import datetime
 from pathlib import Path
-from typing import List
+from typing import Any, Dict, List
 
 import yaml
 import zmq
@@ -128,9 +128,8 @@ async def upload_config(socket, config, yaml, instrument, cycle, proposal):
     socket.send(Success.UPLOADED_CONFIG.format(cycle, proposal).encode())
 
 
-def merge(source, destination):
-    """
-    Deep merge two dictionaries
+def merge(source: Dict, destination: Dict) -> Dict:
+    """Deep merge two dictionaries.
 
     :param source: source dictionary to merge into destination
     :param destination: destination dictionary which is being merged in
@@ -284,16 +283,27 @@ async def query_rid(conn, socket, rid):
     socket.send(msg.encode())
 
 
-def parse_config(cmd, config):
+def parse_config(cmd: List[str], config: Dict[str, Any]) -> List[str]:
+    """Convert a dictionary to a list of arguments.
+
+       Values that are not strings will be cast.
+       Lists will be converted to several strings following their `--key`
+       flag.
+       Booleans will be converted to a `--key` flag, where `key` is the
+       dictionary key.
+    """
     for key, value in config.items():
+        if ' ' in key or (isinstance(value, str) and ' ' in value):
+            raise ValueError('Spaces are not allowed', key, value)
+
         if isinstance(value, list):
-            cmd += ["--{}".format(key)]
+            cmd.append(f"--{key}")
             cmd += [str(v) for v in value]
         elif isinstance(value, bool):
             if value:
                 cmd += ["--{}".format(key)]
         else:
-            if value == '""' or value == "''":
+            if value in ['""', "''"]:
                 value = ""
             cmd += ["--{}".format(key), str(value)]