Updated mapping test API for 0.20

* Reimplemented connection tests to work with `RKConnectionDescription`. Introduced new `RKConnectionTestExpectation` class
* Slimmed down API by removing proxy methods on `RKMappingTest`
* Eliminated `verifiesOnExpect` behavior in favor of using `evaluateExpectation:`
* Ensured compatibility with RKKiwiMatchers

Code/Testing/RKConnectionTestExpectation.m

@@ -0,0 +1,66 @@
+//
+//  RKConnectionTestExpectation.m
+//  RestKit
+//
+//  Created by Blake Watters on 12/8/12.
+//  Copyright (c) 2012 RestKit. All rights reserved.
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+//
+
+#import <CoreData/CoreData.h>
+#import "RKConnectionTestExpectation.h"
+#import "RKObjectUtilities.h"
+
+@interface RKConnectionTestExpectation ()
+@property (nonatomic, copy, readwrite) NSString *relationshipName;
+@property (nonatomic, copy, readwrite) NSDictionary *attributes;
+@property (nonatomic, strong, readwrite) id value;
+@end
+
+@implementation RKConnectionTestExpectation
+
++ (id)expectationWithRelationshipName:(NSString *)relationshipName attributes:(NSDictionary *)attributes value:(id)value
+{
+    return [[self alloc] initWithRelationshipName:relationshipName attributes:attributes value:value];
+}
+
+- (id)initWithRelationshipName:(NSString *)relationshipName attributes:(NSDictionary *)attributes value:(id)value
+{
+    NSParameterAssert(relationshipName);
+    NSAssert(value == nil ||
+             [value isKindOfClass:[NSManagedObject class]] ||
+             RKObjectIsCollectionContainingOnlyManagedObjects(value), @"Can only expect a connection to `nil`, a `NSManagedObject`, or a collection of `NSManagedObject` objects");
+    self = [self init];
+    if (self) {
+        self.relationshipName = relationshipName;
+        self.attributes = attributes;
+        self.value = value;
+    }
+    return self;
+}
+
+- (NSString *)summary
+{
+    return [NSString stringWithFormat:@"connect relationship '%@'", self.relationshipName];
+}
+
+- (NSString *)description
+{
+    NSMutableString *description = [[self summary] mutableCopy];
+    if (self.attributes) [description appendFormat:@" using attributes %@", self.attributes];
+    if (self.value) [description appendFormat:@" to value %@", self.value];
+    return description;
+}
+
+@end