Expanded specs and began migrating all the content for testing out in the Fixtures directory. Fixtures is now the root for the Sinatra app and there are new helpers in RKSpecEnvironment.m. Added specs for several users use cases from the mailing list. Introduced a new warning when attempting to map did not set any properties.

Code/ObjectMapping/RKObjectMapper.m

@@ -394,6 +394,7 @@ static const NSString* kRKModelMapperRailsDateFormatString = @"MM/dd/yyyy";
 }
 
 - (void)setPropertiesOfModel:(NSObject<RKObjectMappable>*)model fromElements:(NSDictionary*)elements {
+    BOOL anyValuesSet = NO;
 	NSDictionary* elementToPropertyMappings = [self elementToPropertyMappingsForModel:model];
 	for (NSString* elementKeyPath in elementToPropertyMappings) {		
 		id elementValue = nil;
@@ -413,6 +414,7 @@ static const NSString* kRKModelMapperRailsDateFormatString = @"MM/dd/yyyy";
 		}
 		
 		if (setValue) {
+            anyValuesSet = YES;
 			id propertyValue = elementValue;
 			NSString* propertyName = [elementToPropertyMappings objectForKey:elementKeyPath];
 			Class class = [self typeClassForProperty:propertyName ofClass:[model class]];
@@ -449,6 +451,10 @@ static const NSString* kRKModelMapperRailsDateFormatString = @"MM/dd/yyyy";
 			[self updateModel:model ifNewPropertyValue:propertyValue forPropertyNamed:propertyName];
 		}
 	}
+    
+    if (anyValuesSet == NO) {
+        NSLog(@"WARNING: RestKit did not find any mappable values for the specified object. If you have specified an explicit objectClass for mapping, be sure that the keyPath has been set to target your mappable data.");
+    }
 }
 
 - (void)setRelationshipsOfModel:(NSObject<RKObjectMappable>*)object fromElements:(NSDictionary*)elements {