iOS Facebook graph request error when looking up {user-id} path - ios

Question

I'm using test users with the IOS Facebook SDK. I create test users and retrieve one userID. Then I create a graphPath string that resembles the "/me" path: /{user-id}
NSString* userId = [[self.testUserTokens objectAtIndex:0] userID];
NSString* graphPath = [NSString stringWithFormat:#"/%#", userId];
Then I make the graph request.
FBSDKGraphRequest *request = [[FBSDKGraphRequest alloc] initWithGraphPath:graphPath parameters:#{#"fields": #"name, id"}];
FBSDKGraphRequestConnection *connection = [[FBSDKGraphRequestConnection alloc] init];
[connection addRequest:request
completionHandler:^(FBSDKGraphRequestConnection *connection, id result, NSError *error) {
NSLog(#"data = %#", result);
if (error)
NSLog(#"error = %#", error);
//TODO: process me information
}];
[connection start];
This returns a 400 "Bad Request" error. I don't understand why at all, I thought I was following the correct format from the Facebook documentation. Does anyone know what I'm doing wrong? I figure it's just a small mistake I can't notice.
Edit: After using the Facebook Graph Explorer, it appears that a /{user-id} request works correctly, using my own Facebook User ID for instance. But it does not work with the IDs of my test users, which I can retrieve either in the Roles panel of Facebook Developers Dashboard or in my app using the method above. For my own ID, I notice that it is different whether I'm retrieving it from the Graph Explorer or from my app, which is logical considering Facebook explains IDs differ based on the app being used, I believe.
Doing the request above using my own personal ID, retrieved using [FBSDKAccessToken currentAccessToken].userId works perfectly fine. So the issue seems to stem from the test user IDs.

Answer 1

Facebook Developer support has resolved this issue for me after I submitted it as a bug.
Turns out it was required to pass a user access token, which I assume is required when wanting to access direct {user-id} data instead of "me" data.
The code thus looks like this:
[testManager requestTestAccountTokensWithArraysOfPermissions: #[[NSSet setWithObjects:#"email", #"user_friends", nil], [NSSet setWithObjects:#"email", #"user_friends", nil]] createIfNotFound:NO completionHandler:^(NSArray* tokens, NSError* error)
{
self.testUserTokens = tokens;
NSLog(#"token1 = %#", [[self.testUserTokens objectAtIndex:0] tokenString]);
NSString* userId = [[self.testUserTokens objectAtIndex:0] userID];
NSString *accessToken = [[self.testUserTokens objectAtIndex:0] tokenString];
NSString* graphPath = [NSString stringWithFormat:#"/%#", userId];
NSLog(#"graphPath = %#", graphPath);
[[[FBSDKGraphRequest alloc] initWithGraphPath:graphPath parameters:#{#"fields": #"name, id, email"} tokenString:accessToken version:nil HTTPMethod:#"GET"] startWithCompletionHandler:^(FBSDKGraphRequestConnection* connection, id result, NSError* error)
{
NSLog(#"data = %#", result);
if (error)
NSLog(#"error = %#", error);
}];