allow pre-loading API tokens from config

This is the first small part of easing the pain of services,
which is generating the API tokens,
and used to require initializing the JupyterHub database.

jupyterhub/tests/test_app.py

@@ -6,6 +6,7 @@ import sys
 from subprocess import check_output, Popen, PIPE
 from tempfile import NamedTemporaryFile, TemporaryDirectory
 from .mocking import MockHub
+from .. import orm
 
 def test_help_all():
     out = check_output([sys.executable, '-m', 'jupyterhub', '--help-all']).decode('utf8', 'replace')
@@ -48,3 +49,30 @@ def test_generate_config():
     assert cfg_file in out
     assert 'Spawner.cmd' in cfg_text
     assert 'Authenticator.whitelist' in cfg_text
+
+def test_init_tokens():
+    with TemporaryDirectory() as td:
+        db_file = os.path.join(td, 'jupyterhub.sqlite')
+        tokens = {
+            'super-secret-token': 'alyx',
+            'also-super-secret': 'gordon',
+            'boagasdfasdf': 'chell',
+        }
+        app = MockHub(db_file=db_file, api_tokens=tokens)
+        app.initialize([])
+        db = app.db
+        for token, username in tokens.items():
+            api_token = orm.APIToken.find(db, token)
+            assert api_token is not None
+            user = api_token.user
+            assert user.name == username
+        
+        # simulate second startup, reloading same tokens:
+        app = MockHub(db_file=db_file, api_tokens=tokens)
+        app.initialize([])
+        db = app.db
+        for token, username in tokens.items():
+            api_token = orm.APIToken.find(db, token)
+            assert api_token is not None
+            user = api_token.user
+            assert user.name == username