diff --git a/tests/test_configurer.py b/tests/test_configurer.py
new file mode 100644
index 0000000..cb4f2b7
--- /dev/null
+++ b/tests/test_configurer.py
@@ -0,0 +1,127 @@
+"""
+Test
+"""
+
+from tljh import configurer
+
+
+class MockConfigurer:
+    """
+    Mock a Traitlet Configurable object.
+
+    Equivalent to the `c` in `c.JupyterHub.some_property` method of setting
+    traitlet properties. If an accessed attribute doesn't exist, a new instance
+    of EmtpyObject is returned. This lets us set arbitrary attributes two
+    levels deep.
+
+      >>> c = MockConfigurer()
+      >>> c.FirstLevel.second_level = 'hi'
+      >>> c.FirstLevel.second_level == 'hi'
+      True
+      >>> hasattr(c.FirstLevel, 'does_not_exist')
+      False
+    """
+
+    class _EmptyObject:
+        """
+        Empty class for putting attributes in.
+        """
+        pass
+
+    def __getattr__(self, k):
+        if k not in self.__dict__:
+            self.__dict__[k] = MockConfigurer._EmptyObject()
+        return self.__dict__[k]
+
+
+def test_mock_configurer():
+    """
+    Test the MockConfigurer's mocking ability
+    """
+    m = MockConfigurer()
+    m.SomethingSomething = 'hi'
+    m.FirstLevel.second_level = 'boo'
+
+    assert m.SomethingSomething == 'hi'
+    assert m.FirstLevel.second_level == 'boo'
+
+    assert not hasattr(m.FirstLevel, 'non_existent')
+
+
+def apply_mock_config(overrides):
+    """
+    Configure a mock configurer with given overrides.
+
+    overrides should be a dict that matches what you parse from a config.yaml
+    """
+    c = MockConfigurer()
+    configurer.apply_config(overrides, c)
+    return c
+
+
+def test_app_default():
+    """
+    Test default application with no config overrides.
+    """
+    c = apply_mock_config({})
+    # default_url is not set, so JupyterHub will pick default.
+    assert not hasattr(c.Spawner, 'default_url')
+
+
+def test_app_jupyterlab():
+    """
+    Test setting JupyterLab as default application
+    """
+    c = apply_mock_config({'user_environment': {'default_app': 'jupyterlab'}})
+    assert c.Spawner.default_url == '/lab'
+
+
+def test_app_nteract():
+    """
+    Test setting nteract as default application
+    """
+    c = apply_mock_config({'user_environment': {'default_app': 'nteract'}})
+    assert c.Spawner.default_url == '/nteract'
+
+
+def test_auth_default():
+    """
+    Test default authentication settings with no overrides
+    """
+    c = apply_mock_config({})
+
+    assert c.JupyterHub.authenticator_class == 'firstuseauthenticator.FirstUseAuthenticator'
+    # Do not auto create users who haven't been manually added by default
+    assert not c.FirstUseAuthenticator.create_users
+
+
+def test_auth_dummy():
+    """
+    Test setting Dummy Authenticator & password
+    """
+    c = apply_mock_config({
+        'auth': {
+            'type': 'dummy',
+            'dummy': {
+                'password': 'test'
+            }
+        }
+    })
+    assert c.JupyterHub.authenticator_class == 'dummyauthenticator.DummyAuthenticator'
+    assert c.DummyAuthenticator.password == 'test'
+
+
+def test_auth_firstuse():
+    """
+    Test setting FirstUse Authenticator options
+    """
+    c = apply_mock_config({
+        'auth': {
+            'type': 'firstuse',
+            'firstuse': {
+                'create_users': True
+            }
+        }
+    })
+    assert c.JupyterHub.authenticator_class == 'firstuseauthenticator.FirstUseAuthenticator'
+    assert c.FirstUseAuthenticator.create_users