Convert getCheckout to use token.

Mobile Buy SDK/Mobile Buy SDK Tests/BUYIntegrationTest.m

@@ -933,11 +933,7 @@
 	[OHHTTPStubs stubUsingResponseWithKey:@"testGetCheckoutWithInvalidToken_0" useMocks:[self shouldUseMocks]];
 	
 	XCTestExpectation *expectation = [self expectationWithDescription:NSStringFromSelector(_cmd)];
-
-	BUYCheckout *badCheckout = [[BUYCheckout alloc] initWithCartToken:@""];
-	badCheckout.token = @"zzzzzzzzzzz";
-	
-	[self.client getCheckout:badCheckout completion:^(BUYCheckout *checkout, NSError *error) {
+	[self.client getCheckoutWithToken:@"zzzzzzzzzzz" completion:^(BUYCheckout *checkout, NSError *error) {
 		
 		XCTAssertEqual(404, error.code);
 		[expectation fulfill];

Mobile Buy SDK/Mobile Buy SDK/Data/BUYClient+Checkout.h

@@ -109,17 +109,17 @@ typedef void (^BUYDataGiftCardBlock)(BUYGiftCard * _Nullable giftCard, NSError *
 - (BUYRequestOperation *)updateCheckout:(BUYCheckout *)checkout completion:(BUYDataCheckoutBlock)block;
 
 /**
- *  Retrieves an updated version of a BUYCheckout from Shopify.
+ *  Retrieves an updated BUYCheckout.
  *
  *  Note: There's no guarantee that the BUYCheckout returned will be the same as the one that is passed in.
  *  We recommended using the BUYCheckout returned in the block.
  *
- *  @param checkout The BUYCheckout to retrieve (updated) from Shopify
+ *  @param checkoutToken The checkout token for which to retrieve the updated checkout
  *  @param block         (^BUYDataCheckoutBlock)(BUYCheckout *checkout, NSError *error);
  *
  *  @return The associated BUYRequestOperation
  */
-- (BUYRequestOperation *)getCheckout:(BUYCheckout *)checkout completion:(BUYDataCheckoutBlock)block;
+- (BUYRequestOperation *)getCheckoutWithToken:(NSString *)checkoutToken completion:(BUYDataCheckoutBlock)block;
 
 /**
  *  Finalizes the BUYCheckout and charges the payment provider (ex: Credit Card, Apple Pay, etc).

Mobile Buy SDK/Mobile Buy SDK/Data/BUYClient+Checkout.m

@@ -77,16 +77,16 @@
 	}];
 }
 
-- (BUYRequestOperation *)getCheckout:(BUYCheckout *)checkout completion:(BUYDataCheckoutBlock)block
+- (BUYRequestOperation *)getCheckoutWithToken:(NSString *)checkoutToken completion:(BUYDataCheckoutBlock)block
 {
-	return [self getCheckout:checkout start:YES completion:block];
+	return [self getCheckoutWithToken:checkoutToken start:YES completion:block];
 }
 
-- (BUYRequestOperation *)getCheckout:(BUYCheckout *)checkout start:(BOOL)start completion:(BUYDataCheckoutBlock)block
+- (BUYRequestOperation *)getCheckoutWithToken:(NSString *)checkoutToken start:(BOOL)start completion:(BUYDataCheckoutBlock)block
 {
-	BUYAssertCheckout(checkout);
+	BUYAssertToken(checkoutToken);
 	
-	NSURL *url = [self urlForCheckoutsWithToken:checkout.token];
+	NSURL *url = [self urlForCheckoutsWithToken:checkoutToken];
 	return [self getRequestForURL:url start:start completionHandler:^(NSDictionary *json, NSHTTPURLResponse *response, NSError *error) {
 		[self handleCheckoutResponse:json error:error block:block];
 	}];

Mobile Buy SDK/Mobile Buy SDK/Data/BUYClient+Internal.h

@@ -64,6 +64,6 @@ typedef void (^BUYClientRequestJSONCompletion)(NSDictionary *json, NSHTTPURLResp
 
 - (BUYRequestOperation *)beginCheckout:(BUYCheckout *)checkout paymentToken:(id<BUYPaymentToken>)paymentToken completion:(BUYDataCheckoutBlock)block;
 - (BUYRequestOperation *)getCompletionStatusOfCheckoutWithToken:(NSString *)token start:(BOOL)start completion:(BUYDataStatusBlock)block;
-- (BUYRequestOperation *)getCheckout:(BUYCheckout *)checkout start:(BOOL)start completion:(BUYDataCheckoutBlock)block;
+- (BUYRequestOperation *)getCheckoutWithToken:(NSString *)checkoutToken start:(BOOL)start completion:(BUYDataCheckoutBlock)block;
 
 @end

Mobile Buy SDK/Mobile Buy SDK/Operations/BUYCheckoutOperation.m

@@ -161,7 +161,7 @@
 
 - (BUYRequestOperation *)createGetOperation
 {
-	return [self.client getCheckout:self.checkout start:NO completion:^(BUYCheckout *checkout, NSError *error) {
+	return [self.client getCheckoutWithToken:self.checkout.token start:NO completion:^(BUYCheckout *checkout, NSError *error) {
 		if (checkout) {
 			[self finishWithCheckout:checkout];
 		} else {