CodeUnderTest.m

- (TOCFuture *)updateAccount {
    self.saveButton.enabled = NO;
    
    BGLManagedAccountEditor *const accountEditor = [self newAccountEditor];
    [accountEditor setContributesToAggregateTotals:self.settingsSession.contributesToAggregateTotals];
    [accountEditor setLowFundsAlertEnabled:self.settingsSession.lowBalanceAlertEnabled];
    [accountEditor setLowFundsAlertThreshold:self.settingsSession.lowBalanceThreshold];
    [accountEditor setAccountType:[BGLManagedAccount accountTypeForAccountClass:self.settingsSession.accountClass]];
    [accountEditor setFavorited:self.settingsSession.favorite];
    
    TOCFuture *accountFuture = [accountEditor persistUnless:nil];
    
    MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:self.view animated:YES];
    hud.labelText = NSLocalizedString(@"Loading", @"Loading label");

    [accountFuture catchDo:^(id value) {
        [hud hide:YES];
        [self.navigationController popViewControllerAnimated:YES];
    }];
    
    [accountFuture thenDo:^(id failure){
        self.saveButton.enabled = YES;
        NSError *error = failure;
        UIAlertController *const alertController = [self createAlertControllerWithMessage:error.localizedDescription];
        [hud hide:YES];
        [self presentViewController:alertController animated:YES completion:nil];
    }];
    
    return accountFuture;
}