Unit test api

* adds unit test for APIUserToken
* enhances handling of token fetching for API

api/models/token.py

@@ -14,7 +14,7 @@ class APIUserToken(models.Model):
     valid_until = models.DateField(
         blank=True,
         null=True,
-        help_text="Token is only valid until this date",
+        help_text="Token is only valid until this date. Forever if null/blank.",
     )
     is_active = models.BooleanField(
         default=False,
@@ -25,12 +25,11 @@ class APIUserToken(models.Model):
         return self.token
 
     @staticmethod
-    def get_user_from_token(token: str, username: str):
+    def get_user_from_token(token: str):
         """ Getter for the related user object
 
         Args:
             token (str): The used token
-            username (str): The username
 
         Returns:
             user (User): Otherwise None
@@ -39,7 +38,6 @@ class APIUserToken(models.Model):
         try:
             token_obj = APIUserToken.objects.get(
                 token=token,
-                user__username=username
             )
             if not token_obj.is_active:
                 raise PermissionError("Token unverified")