auth: Implement `create_resource` function

* gn3/auth/authentication/checks.py: new `authenticated_p` decorator to apply
  on any function that requires the user to be authenticated before it runs.
* gn3/auth/authorisation/checks.py: use a `auth.authentication.users.User`
  object rather than a UUID object in the global `g`.
* gn3/auth/authorisation/groups.py: Implement the `authenticated_user_group`
  function to get the group(s) in which the currently authenticated user
  belongs.
* gn3/auth/authorisation/resources.py: Implement the `create_resource`
  function correctly.
* tests/unit/auth/conftest.py: extract the User objects into a global variable
  for reusability with the tests.
* tests/unit/auth/test_resources.py: Use global user objects from conftest in
  the tests. Set a User object (rather than UUID) in the global `g` variable.

1 files changed, 14 insertions, 0 deletions

diff --git a/gn3/auth/authentication/checks.py b/gn3/auth/authentication/checks.py
new file mode 100644
index 0000000..63b0752
--- /dev/null
+++ b/gn3/auth/authentication/checks.py
@@ -0,0 +1,14 @@
+"""Functions to check for user authentication."""
+
+from flask import g
+
+from .exceptions import AuthenticationError
+
+def authenticated_p(func):
+    """Decorator for functions requiring authentication."""
+    def __authenticated__(*args, **kwargs):
+        user = g.user if hasattr(g, "user") else False
+        if user:
+            return func(*args, **kwargs)
+        raise AuthenticationError("You need to be authenticated")
+    return __authenticated__