Add test to verify that non-trivial keypaths work

KJSimpleBindingTests/KJBindingManagerTests.m

@@ -30,17 +30,20 @@ @interface TestModel : NSObject
 @property (nonatomic, copy) NSString *stringValue;
 @property (nonatomic, copy) NSString *stringValue2;
 @property (nonatomic) NSInteger numericValue;
+@property (nonatomic, retain) TestModel *submodel;
 @end
 
 @implementation TestModel
 
 @synthesize stringValue;
 @synthesize stringValue2;
 @synthesize numericValue;
+@synthesize submodel;
 
 - (void)dealloc {
     [stringValue release];
     [stringValue2 release];
+    [submodel release];
     [super dealloc];
 }
 
@@ -263,4 +266,22 @@ - (void)testValueTransform {
     STAssertEqualObjects(@"22", observer.text, nil);
 }
 
+- (void)testSubjectKeyPath {
+    TestModel *topModel = [[[TestModel alloc] init] autorelease];
+    TestModel *subModel = [[[TestModel alloc] init] autorelease];
+
+    topModel.submodel = subModel;
+
+    TestObserver *observer = [[[TestObserver alloc] init] autorelease];
+
+    // Bind to topModel, but use a key path to actually bind to its submodel's stringValue
+    [bindingManager bindObserver:observer keyPath:@"text"
+                       toSubject:topModel keyPath:@"submodel.stringValue"];
+    [bindingManager enable];
+
+    subModel.stringValue = @"Submodel value";
+
+    STAssertEqualObjects(@"Submodel value", observer.text, nil);
+}
+
 @end