diff --git a/jupyterhub/tests/test_api.py b/jupyterhub/tests/test_api.py
index a3e3e843..c5d83092 100644
--- a/jupyterhub/tests/test_api.py
+++ b/jupyterhub/tests/test_api.py
@@ -134,7 +134,7 @@ def test_auth_api(app):
 
 
 @mark.gen_test
-def test_referer_check(app, io_loop):
+def test_referer_check(app):
     url = ujoin(public_host(app), app.hub.base_url)
     host = urlparse(url).netloc
     user = find_user(app.db, 'admin')
@@ -390,7 +390,7 @@ def test_make_admin(app):
 
 
 @mark.gen_test
-def test_spawn(app, io_loop):
+def test_spawn(app):
     db = app.db
     name = 'wash'
     user = add_user(db, app=app, name=name)
@@ -445,7 +445,7 @@ def test_spawn(app, io_loop):
 
 
 @mark.gen_test
-def test_slow_spawn(app, io_loop, no_patience, request):
+def test_slow_spawn(app, no_patience, request):
     patch = mock.patch.dict(app.tornado_settings, {'spawner_class': mocking.SlowSpawner})
     patch.start()
     request.addfinalizer(patch.stop)
@@ -495,7 +495,7 @@ def test_slow_spawn(app, io_loop, no_patience, request):
 
 
 @mark.gen_test
-def test_never_spawn(app, io_loop, no_patience, request):
+def test_never_spawn(app, no_patience, request):
     patch = mock.patch.dict(app.tornado_settings, {'spawner_class': mocking.NeverSpawner})
     patch.start()
     request.addfinalizer(patch.stop)
@@ -520,7 +520,7 @@ def test_never_spawn(app, io_loop, no_patience, request):
 
 
 @mark.gen_test
-def test_get_proxy(app, io_loop):
+def test_get_proxy(app):
     r = yield api_request(app, 'proxy')
     r.raise_for_status()
     reply = r.json()
diff --git a/jupyterhub/tests/test_app.py b/jupyterhub/tests/test_app.py
index e879efeb..2f9af395 100644
--- a/jupyterhub/tests/test_app.py
+++ b/jupyterhub/tests/test_app.py
@@ -56,7 +56,9 @@ def test_generate_config():
     assert 'Spawner.cmd' in cfg_text
     assert 'Authenticator.whitelist' in cfg_text
 
-def test_init_tokens(io_loop):
+
+@pytest.mark.gen_test
+def test_init_tokens():
     with TemporaryDirectory() as td:
         db_file = os.path.join(td, 'jupyterhub.sqlite')
         tokens = {
@@ -65,7 +67,7 @@ def test_init_tokens(io_loop):
             'boagasdfasdf': 'chell',
         }
         app = MockHub(db_url=db_file, api_tokens=tokens)
-        io_loop.run_sync(lambda : app.initialize([]))
+        yield app.initialize([])
         db = app.db
         for token, username in tokens.items():
             api_token = orm.APIToken.find(db, token)
@@ -75,7 +77,7 @@ def test_init_tokens(io_loop):
 
         # simulate second startup, reloading same tokens:
         app = MockHub(db_url=db_file, api_tokens=tokens)
-        io_loop.run_sync(lambda : app.initialize([]))
+        yield app.initialize([])
         db = app.db
         for token, username in tokens.items():
             api_token = orm.APIToken.find(db, token)
@@ -87,7 +89,7 @@ def test_init_tokens(io_loop):
         tokens['short'] = 'gman'
         app = MockHub(db_url=db_file, api_tokens=tokens)
         with pytest.raises(ValueError):
-            io_loop.run_sync(lambda : app.initialize([]))
+            yield app.initialize([])
         assert orm.User.find(app.db, 'gman') is None
 
 
@@ -141,15 +143,16 @@ def test_cookie_secret_env(tmpdir):
     assert not os.path.exists(hub.cookie_secret_file)
 
 
-def test_load_groups(io_loop):
+@pytest.mark.gen_test
+def test_load_groups():
     to_load = {
         'blue': ['cyclops', 'rogue', 'wolverine'],
         'gold': ['storm', 'jean-grey', 'colossus'],
     }
     hub = MockHub(load_groups=to_load)
     hub.init_db()
-    io_loop.run_sync(hub.init_users)
-    hub.init_groups()
+    yield hub.init_users()
+    yield hub.init_groups()
     db = hub.db
     blue = orm.Group.find(db, name='blue')
     assert blue is not None
@@ -158,6 +161,3 @@ def test_load_groups(io_loop):
     assert gold is not None
     assert sorted([ u.name for u in gold.users ]) == sorted(to_load['gold'])
 
-def test_version():
-    if sys.version_info[:2] < (3, 3):
-        assertRaises(ValueError)
diff --git a/jupyterhub/tests/test_auth.py b/jupyterhub/tests/test_auth.py
index 9e63c017..680536be 100644
--- a/jupyterhub/tests/test_auth.py
+++ b/jupyterhub/tests/test_auth.py
@@ -10,38 +10,42 @@ from .mocking import MockPAMAuthenticator
 
 from jupyterhub import auth, orm
 
-def test_pam_auth(io_loop):
+
+@pytest.mark.gen_test
+def test_pam_auth():
     authenticator = MockPAMAuthenticator()
-    authorized = io_loop.run_sync(lambda : authenticator.get_authenticated_user(None, {
+    authorized = yield authenticator.get_authenticated_user(None, {
         'username': 'match',
         'password': 'match',
-    }))
+    })
     assert authorized['name'] == 'match'
     
-    authorized = io_loop.run_sync(lambda : authenticator.get_authenticated_user(None, {
+    authorized = yield authenticator.get_authenticated_user(None, {
         'username': 'match',
         'password': 'nomatch',
-    }))
+    })
     assert authorized is None
 
-def test_pam_auth_whitelist(io_loop):
+
+@pytest.mark.gen_test
+def test_pam_auth_whitelist():
     authenticator = MockPAMAuthenticator(whitelist={'wash', 'kaylee'})
-    authorized = io_loop.run_sync(lambda : authenticator.get_authenticated_user(None, {
+    authorized = yield authenticator.get_authenticated_user(None, {
         'username': 'kaylee',
         'password': 'kaylee',
-    }))
+    })
     assert authorized['name'] == 'kaylee'
     
-    authorized = io_loop.run_sync(lambda : authenticator.get_authenticated_user(None, {
+    authorized = yield authenticator.get_authenticated_user(None, {
         'username': 'wash',
         'password': 'nomatch',
-    }))
+    })
     assert authorized is None
     
-    authorized = io_loop.run_sync(lambda : authenticator.get_authenticated_user(None, {
+    authorized = yield authenticator.get_authenticated_user(None, {
         'username': 'mal',
         'password': 'mal',
-    }))
+    })
     assert authorized is None
 
 
@@ -50,7 +54,8 @@ class MockGroup:
         self.gr_mem = names
 
 
-def test_pam_auth_group_whitelist(io_loop):
+@pytest.mark.gen_test
+def test_pam_auth_group_whitelist():
     g = MockGroup('kaylee')
     def getgrnam(name):
         return g
@@ -58,38 +63,41 @@ def test_pam_auth_group_whitelist(io_loop):
     authenticator = MockPAMAuthenticator(group_whitelist={'group'})
     
     with mock.patch.object(auth, 'getgrnam', getgrnam):
-        authorized = io_loop.run_sync(lambda : authenticator.get_authenticated_user(None, {
+        authorized = yield authenticator.get_authenticated_user(None, {
             'username': 'kaylee',
             'password': 'kaylee',
-        }))
+        })
     assert authorized['name'] == 'kaylee'
 
     with mock.patch.object(auth, 'getgrnam', getgrnam):
-        authorized = io_loop.run_sync(lambda : authenticator.get_authenticated_user(None, {
+        authorized = yield authenticator.get_authenticated_user(None, {
             'username': 'mal',
             'password': 'mal',
-        }))
+        })
     assert authorized is None
 
 
-def test_pam_auth_no_such_group(io_loop):
+@pytest.mark.gen_test
+def test_pam_auth_no_such_group():
     authenticator = MockPAMAuthenticator(group_whitelist={'nosuchcrazygroup'})
-    authorized = io_loop.run_sync(lambda : authenticator.get_authenticated_user(None, {
+    authorized = yield authenticator.get_authenticated_user(None, {
         'username': 'kaylee',
         'password': 'kaylee',
-    }))
+    })
     assert authorized is None
 
 
-def test_wont_add_system_user(io_loop):
+@pytest.mark.gen_test
+def test_wont_add_system_user():
     user = orm.User(name='lioness4321')
     authenticator = auth.PAMAuthenticator(whitelist={'mal'})
     authenticator.create_system_users = False
     with pytest.raises(KeyError):
-        io_loop.run_sync(lambda : authenticator.add_user(user))
+        yield authenticator.add_user(user)
 
 
-def test_cant_add_system_user(io_loop):
+@pytest.mark.gen_test
+def test_cant_add_system_user():
     user = orm.User(name='lioness4321')
     authenticator = auth.PAMAuthenticator(whitelist={'mal'})
     authenticator.add_user_cmd = ['jupyterhub-fake-command']
@@ -111,11 +119,12 @@ def test_cant_add_system_user(io_loop):
     
     with mock.patch.object(auth, 'Popen', DummyPopen):
         with pytest.raises(RuntimeError) as exc:
-            io_loop.run_sync(lambda : authenticator.add_user(user))
+            yield authenticator.add_user(user)
         assert str(exc.value) == 'Failed to create system user lioness4321: dummy error'
 
 
-def test_add_system_user(io_loop):
+@pytest.mark.gen_test
+def test_add_system_user():
     user = orm.User(name='lioness4321')
     authenticator = auth.PAMAuthenticator(whitelist={'mal'})
     authenticator.create_system_users = True
@@ -131,11 +140,12 @@ def test_add_system_user(io_loop):
             return
     
     with mock.patch.object(auth, 'Popen', DummyPopen):
-        io_loop.run_sync(lambda : authenticator.add_user(user))
+        yield authenticator.add_user(user)
     assert record['cmd'] == ['echo', '/home/lioness4321', 'lioness4321']
 
 
-def test_delete_user(io_loop):
+@pytest.mark.gen_test
+def test_delete_user():
     user = orm.User(name='zoe')
     a = MockPAMAuthenticator(whitelist={'mal'})
     
@@ -160,49 +170,52 @@ def test_handlers(app):
     assert handlers[0][0] == '/login'
 
 
-def test_normalize_names(io_loop):
+@pytest.mark.gen_test
+def test_normalize_names():
     a = MockPAMAuthenticator()
-    authorized = io_loop.run_sync(lambda : a.get_authenticated_user(None, {
+    authorized = yield a.get_authenticated_user(None, {
         'username': 'ZOE',
         'password': 'ZOE',
-    }))
+    })
     assert authorized['name'] == 'zoe'
 
-    authorized = io_loop.run_sync(lambda: a.get_authenticated_user(None, {
+    authorized = yield a.get_authenticated_user(None, {
         'username': 'Glenn',
         'password': 'Glenn',
-    }))
+    })
     assert authorized['name'] == 'glenn'
 
-    authorized = io_loop.run_sync(lambda: a.get_authenticated_user(None, {
+    authorized = yield a.get_authenticated_user(None, {
         'username': 'hExi',
         'password': 'hExi',
-    }))
+    })
     assert authorized['name'] == 'hexi'
 
-    authorized = io_loop.run_sync(lambda: a.get_authenticated_user(None, {
+    authorized = yield a.get_authenticated_user(None, {
         'username': 'Test',
         'password': 'Test',
-    }))
+    })
     assert authorized['name'] == 'test'
 
-def test_username_map(io_loop):
+
+@pytest.mark.gen_test
+def test_username_map():
     a = MockPAMAuthenticator(username_map={'wash': 'alpha'})
-    authorized = io_loop.run_sync(lambda : a.get_authenticated_user(None, {
+    authorized = yield a.get_authenticated_user(None, {
         'username': 'WASH',
         'password': 'WASH',
-    }))
+    })
 
     assert authorized['name'] == 'alpha'
 
-    authorized = io_loop.run_sync(lambda : a.get_authenticated_user(None, {
+    authorized = yield a.get_authenticated_user(None, {
         'username': 'Inara',
         'password': 'Inara',
-    }))
+    })
     assert authorized['name'] == 'inara'
 
 
-def test_validate_names(io_loop):
+def test_validate_names():
     a = auth.PAMAuthenticator()
     assert a.validate_username('willow')
     assert a.validate_username('giles')
diff --git a/jupyterhub/tests/test_db.py b/jupyterhub/tests/test_db.py
index 45f857d7..8950fd2f 100644
--- a/jupyterhub/tests/test_db.py
+++ b/jupyterhub/tests/test_db.py
@@ -3,6 +3,8 @@ import os
 import shutil
 
 from sqlalchemy.exc import OperationalError
+
+import pytest
 from pytest import raises
 
 from ..dbutil import upgrade
@@ -24,7 +26,8 @@ def test_upgrade(tmpdir):
     print(db_url)
     upgrade(db_url)
 
-def test_upgrade_entrypoint(tmpdir, io_loop):
+@pytest.mark.gen_test
+def test_upgrade_entrypoint(tmpdir):
     generate_old_db(str(tmpdir))
     tmpdir.chdir()
     tokenapp = NewToken()
@@ -36,7 +39,7 @@ def test_upgrade_entrypoint(tmpdir, io_loop):
     assert len(sqlite_files) == 1
 
     upgradeapp = UpgradeDB()
-    io_loop.run_sync(lambda : upgradeapp.initialize([]))
+    yield upgradeapp.initialize([])
     upgradeapp.start()
 
     # check that backup was created:
diff --git a/jupyterhub/tests/test_orm.py b/jupyterhub/tests/test_orm.py
index 4fb8f598..7b6bafc3 100644
--- a/jupyterhub/tests/test_orm.py
+++ b/jupyterhub/tests/test_orm.py
@@ -140,7 +140,8 @@ def test_token_find(db):
     assert found is None
 
 
-def test_spawn_fails(db, io_loop):
+@pytest.mark.gen_test
+def test_spawn_fails(db):
     orm_user = orm.User(name='aeofel')
     db.add(orm_user)
     db.commit()
@@ -156,7 +157,7 @@ def test_spawn_fails(db, io_loop):
     })
     
     with pytest.raises(RuntimeError) as exc:
-        io_loop.run_sync(user.spawn)
+        yield user.spawn()
     assert user.spawners[''].server is None
     assert not user.running('')
 
diff --git a/jupyterhub/tests/test_spawner.py b/jupyterhub/tests/test_spawner.py
index 6b546741..e2e01eb7 100644
--- a/jupyterhub/tests/test_spawner.py
+++ b/jupyterhub/tests/test_spawner.py
@@ -96,7 +96,7 @@ def wait_for_spawner(spawner, timeout=10):
     yield wait()
 
 
-@pytest.mark.gen_test(run_sync=False)
+@pytest.mark.gen_test
 def test_single_user_spawner(app, request):
     user = next(iter(app.users.values()), None)
     spawner = user.spawner
@@ -112,42 +112,45 @@ def test_single_user_spawner(app, request):
     assert status == 0
 
 
-def test_stop_spawner_sigint_fails(db, io_loop):
+@pytest.mark.gen_test
+def test_stop_spawner_sigint_fails(db):
     spawner = new_spawner(db, cmd=[sys.executable, '-c', _uninterruptible])
-    io_loop.run_sync(spawner.start)
-    
+    yield spawner.start()
+
     # wait for the process to get to the while True: loop
-    time.sleep(1)
-    
-    status = io_loop.run_sync(spawner.poll)
+    yield gen.sleep(1)
+
+    status = yield spawner.poll()
     assert status is None
     
-    io_loop.run_sync(spawner.stop)
-    status = io_loop.run_sync(spawner.poll)
+    yield spawner.stop()
+    status = yield spawner.poll()
     assert status == -signal.SIGTERM
 
 
-def test_stop_spawner_stop_now(db, io_loop):
+@pytest.mark.gen_test
+def test_stop_spawner_stop_now(db):
     spawner = new_spawner(db)
-    io_loop.run_sync(spawner.start)
-    
+    yield spawner.start()
+
     # wait for the process to get to the while True: loop
-    time.sleep(1)
-    
-    status = io_loop.run_sync(spawner.poll)
+    yield gen.sleep(1)
+
+    status = yield spawner.poll()
     assert status is None
     
-    io_loop.run_sync(lambda : spawner.stop(now=True))
-    status = io_loop.run_sync(spawner.poll)
+    yield spawner.stop(now=True)
+    status = yield spawner.poll()
     assert status == -signal.SIGTERM
 
 
-def test_spawner_poll(db, io_loop):
+@pytest.mark.gen_test
+def test_spawner_poll(db):
     first_spawner = new_spawner(db)
     user = first_spawner.user
-    io_loop.run_sync(first_spawner.start)
+    yield first_spawner.start()
     proc = first_spawner.proc
-    status = io_loop.run_sync(first_spawner.poll)
+    status = yield first_spawner.poll()
     assert status is None
     if user.state is None:
         user.state = {}
@@ -159,21 +162,21 @@ def test_spawner_poll(db, io_loop):
     spawner.start_polling()
     
     # wait for the process to get to the while True: loop
-    io_loop.run_sync(lambda : gen.sleep(1))
-    status = io_loop.run_sync(spawner.poll)
+    yield gen.sleep(1)
+    status = yield spawner.poll()
     assert status is None
     
     # kill the process
     proc.terminate()
     for i in range(10):
         if proc.poll() is None:
-            time.sleep(1)
+            yield gen.sleep(1)
         else:
             break
     assert proc.poll() is not None
 
-    io_loop.run_sync(lambda : gen.sleep(2))
-    status = io_loop.run_sync(spawner.poll)
+    yield gen.sleep(2)
+    status = yield spawner.poll()
     assert status is not None