Merge pull request #270 from wangliangliang2/master

 fix github issue #269

Author: longbai

QiniuSDK/Storage/QNUpToken.m

@@ -37,7 +37,7 @@ - (NSString *)getAccess {
 - (NSString *)getBucket:(NSDictionary *)info {
 
     NSString *scope = [info objectForKey:@"scope"];
-    if (!scope) {
+    if (!scope || [scope isKindOfClass:[NSNull class]] ) {
         return @"";
     }
 

QiniuSDKTests/QNUpTokenTest.m

@@ -56,4 +56,11 @@ - (void)testReturnUrl {
     XCTAssert(t.hasReturnUrl, @"Pass");
 }
 
+- (void)testScopeNull {
+    QNUpToken *t = [QNUpToken parse:@"k4MXrVJes7RoS7N7teQDfkVqDDXqNOZq5BOfjzPn:MDllYmMxYTkyNjIxZTg0N2NjYTUwNDg0MGIyOWQxYjhjMTBlZTc0Ngo=:eyJzY29wZSI6bnVsbCwiZGVhZGxpbmUiOjE1MTM3Njg3ODl9Cg=="];
+    // This is an example of a functional test case.
+    XCTAssert([t.bucket isEqualToString:@""], @"Pass");
+}
+
+
 @end