✨ Test if user exists & if already friends before creating friend request

app/routes/friends.py

@@ -44,7 +44,6 @@ async def get_friend(id: str, current_user: User = Depends(get_current_user)):
     responses={401: {"model": HTTPError}, 409: {"model": HTTPError}}
 )
 async def add_friend(friend_to_add: FriendAddDTO, current_user: User = Depends(get_current_user)):
-    # TODO: test if exists
     friend: Friend = friend_to_add.model_dump()
 
     if(current_user.uid == friend["friend_user_id"]):
@@ -53,6 +52,20 @@ async def add_friend(friend_to_add: FriendAddDTO, current_user: User = Depends(g
             detail="Cannot add yourself as a friend"
         )
     
+    # Test if already friends
+    if friends_collection.find_one({"user_id": current_user.uid, "friend_user_id": friend["friend_user_id"]}) is not None:
+        raise HTTPException(
+            status_code=status.HTTP_409_CONFLICT,
+            detail="Friend already exists"
+        )
+    
+    # Test if user exists
+    if db["users"].find_one({"_id": ObjectId(friend["friend_user_id"])}):
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="User not found"
+        )
+
     friend["user_id"] = current_user.uid
     friend["status"] = "pending"
     friend_id = friends_collection.insert_one(friend).inserted_id