Merge pull request #1279 from smartdevicelink/feature/issue_1222_align_systemcapabilitymanager_callbacks

Support SDLSystemCapabilityManager Subscriptions

11 files changed, 514 insertions, 50 deletions

diff --git a/SmartDeviceLink-iOS.xcodeproj/project.pbxproj b/SmartDeviceLink-iOS.xcodeproj/project.pbxproj
index 91cebebb7..46abf3e31 100644
--- a/SmartDeviceLink-iOS.xcodeproj/project.pbxproj
+++ b/SmartDeviceLink-iOS.xcodeproj/project.pbxproj
@@ -1004,6 +1004,9 @@
 		5D6F7A351BC5B9B60070BF37 /* SDLLockScreenViewController.h in Headers */ = {isa = PBXBuildFile; fileRef = 5D6F7A331BC5B9B60070BF37 /* SDLLockScreenViewController.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		5D6F7A361BC5B9B60070BF37 /* SDLLockScreenViewController.m in Sources */ = {isa = PBXBuildFile; fileRef = 5D6F7A341BC5B9B60070BF37 /* SDLLockScreenViewController.m */; };
 		5D6F7A3E1BC811FC0070BF37 /* SDLAssets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 5D6F7A3D1BC811FC0070BF37 /* SDLAssets.xcassets */; };
+		5D75960D22972F830013207C /* TestSystemCapabilityObserver.m in Sources */ = {isa = PBXBuildFile; fileRef = 5D75960C22972F830013207C /* TestSystemCapabilityObserver.m */; };
+		5D75961122972FCA0013207C /* SDLSystemCapabilityObserver.h in Headers */ = {isa = PBXBuildFile; fileRef = 5D75960F22972FCA0013207C /* SDLSystemCapabilityObserver.h */; };
+		5D75961222972FCA0013207C /* SDLSystemCapabilityObserver.m in Sources */ = {isa = PBXBuildFile; fileRef = 5D75961022972FCA0013207C /* SDLSystemCapabilityObserver.m */; };
 		5D76E31C1D3805FF00647CFA /* SDLLockScreenManagerSpec.m in Sources */ = {isa = PBXBuildFile; fileRef = 5D76E31B1D3805FF00647CFA /* SDLLockScreenManagerSpec.m */; };
 		5D76E3211D39742300647CFA /* SDLViewControllerPresentable.h in Headers */ = {isa = PBXBuildFile; fileRef = 5D76E3201D39742300647CFA /* SDLViewControllerPresentable.h */; };
 		5D76E3241D39767000647CFA /* SDLLockScreenPresenter.h in Headers */ = {isa = PBXBuildFile; fileRef = 5D76E3221D39767000647CFA /* SDLLockScreenPresenter.h */; };
@@ -2638,6 +2641,10 @@
 		5D6F7A331BC5B9B60070BF37 /* SDLLockScreenViewController.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SDLLockScreenViewController.h; sourceTree = "<group>"; };
 		5D6F7A341BC5B9B60070BF37 /* SDLLockScreenViewController.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SDLLockScreenViewController.m; sourceTree = "<group>"; };
 		5D6F7A3D1BC811FC0070BF37 /* SDLAssets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; name = SDLAssets.xcassets; path = Assets/SDLAssets.xcassets; sourceTree = "<group>"; };
+		5D75960B22972F830013207C /* TestSystemCapabilityObserver.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; name = TestSystemCapabilityObserver.h; path = DevAPISpecs/TestSystemCapabilityObserver.h; sourceTree = "<group>"; };
+		5D75960C22972F830013207C /* TestSystemCapabilityObserver.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; name = TestSystemCapabilityObserver.m; path = DevAPISpecs/TestSystemCapabilityObserver.m; sourceTree = "<group>"; };
+		5D75960F22972FCA0013207C /* SDLSystemCapabilityObserver.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = SDLSystemCapabilityObserver.h; sourceTree = "<group>"; };
+		5D75961022972FCA0013207C /* SDLSystemCapabilityObserver.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = SDLSystemCapabilityObserver.m; sourceTree = "<group>"; };
 		5D76E31B1D3805FF00647CFA /* SDLLockScreenManagerSpec.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = SDLLockScreenManagerSpec.m; path = DevAPISpecs/SDLLockScreenManagerSpec.m; sourceTree = "<group>"; };
 		5D76E3201D39742300647CFA /* SDLViewControllerPresentable.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SDLViewControllerPresentable.h; sourceTree = "<group>"; };
 		5D76E3221D39767000647CFA /* SDLLockScreenPresenter.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SDLLockScreenPresenter.h; sourceTree = "<group>"; };
@@ -5060,6 +5067,24 @@
 			name = "Lock Screen UI";
 			sourceTree = "<group>";
 		};
+		5D75960A22972F620013207C /* Utilities */ = {
+			isa = PBXGroup;
+			children = (
+				5D75960B22972F830013207C /* TestSystemCapabilityObserver.h */,
+				5D75960C22972F830013207C /* TestSystemCapabilityObserver.m */,
+			);
+			name = Utilities;
+			sourceTree = "<group>";
+		};
+		5D75960E22972FB90013207C /* Utilities */ = {
+			isa = PBXGroup;
+			children = (
+				5D75960F22972FCA0013207C /* SDLSystemCapabilityObserver.h */,
+				5D75961022972FCA0013207C /* SDLSystemCapabilityObserver.m */,
+			);
+			name = Utilities;
+			sourceTree = "<group>";
+		};
 		5D76E31A1D3805E600647CFA /* LockScreen */ = {
 			isa = PBXGroup;
 			children = (
@@ -5782,6 +5807,7 @@
 		880E35B12088F73400181259 /* System Capabilities */ = {
 			isa = PBXGroup;
 			children = (
+				5D75960E22972FB90013207C /* Utilities */,
 				880E35B32088F75A00181259 /* SDLSystemCapabilityManager.h */,
 				880E35B22088F75A00181259 /* SDLSystemCapabilityManager.m */,
 			);
@@ -5791,6 +5817,7 @@
 		880E35B62088F77C00181259 /* System Capabilities */ = {
 			isa = PBXGroup;
 			children = (
+				5D75960A22972F620013207C /* Utilities */,
 				880E35B72088F78E00181259 /* SDLSystemCapabilityManagerSpec.m */,
 			);
 			name = "System Capabilities";
@@ -6315,6 +6342,7 @@
 				5D61FDB11A84238C00846EE7 /* SDLSubscribeVehicleData.h in Headers */,
 				5DB996601F28C6ED002D8795 /* SDLControlFramePayloadVideoStartServiceAck.h in Headers */,
 				5DCF76F51ACDBAD300BB647B /* SDLSendLocation.h in Headers */,
+				5D75961122972FCA0013207C /* SDLSystemCapabilityObserver.h in Headers */,
 				5D61FC9E1A84238C00846EE7 /* SDLEncodedSyncPData.h in Headers */,
 				1FF7DABA1F75B2A800B46C30 /* SDLFocusableItemLocator.h in Headers */,
 				5D019276214994AC003500F6 /* NSMutableArray+Safe.h in Headers */,
@@ -7069,6 +7097,7 @@
 				88EEC5BC220A327B005AA2F9 /* SDLPublishAppServiceResponse.m in Sources */,
 				5D61FC951A84238C00846EE7 /* SDLDriverDistractionState.m in Sources */,
 				5DB996611F28C6ED002D8795 /* SDLControlFramePayloadVideoStartServiceAck.m in Sources */,
+				5D75961222972FCA0013207C /* SDLSystemCapabilityObserver.m in Sources */,
 				884E702021FB983F008D53BA /* SDLAppServiceManifest.m in Sources */,
 				5D61FD961A84238C00846EE7 /* SDLShowResponse.m in Sources */,
 				5D61FD981A84238C00846EE7 /* SDLSingleTireStatus.m in Sources */,
@@ -7415,6 +7444,7 @@
 				162E837E1A9BDE8B00906325 /* SDLGPSDataSpec.m in Sources */,
 				5DAE06731BDEC6C000F9B498 /* SDLFileSpec.m in Sources */,
 				162E82E11A9BDE8B00906325 /* SDLHMIZoneCapabilitiesSpec.m in Sources */,
+				5D75960D22972F830013207C /* TestSystemCapabilityObserver.m in Sources */,
 				88B58DBD222042500011B063 /* SDLDirectionSpec.m in Sources */,
 				162E83721A9BDE8B00906325 /* SDLAudioPassThruCapabilitiesSpec.m in Sources */,
 				162E83681A9BDE8B00906325 /* SDLSpeakResponseSpec.m in Sources */,
diff --git a/SmartDeviceLink/SDLError.h b/SmartDeviceLink/SDLError.h
index 9c6209c5b..280c20309 100644
--- a/SmartDeviceLink/SDLError.h
+++ b/SmartDeviceLink/SDLError.h
@@ -90,6 +90,7 @@ extern SDLErrorDomain *const SDLErrorDomainRPCStore;
 + (NSException *)sdl_invalidSoftButtonStateException;
 + (NSException *)sdl_carWindowOrientationException;
 + (NSException *)sdl_invalidLockscreenSetupException;
++ (NSException *)sdl_invalidSelectorExceptionWithSelector:(SEL)selector;
 
 @end
 
diff --git a/SmartDeviceLink/SDLError.m b/SmartDeviceLink/SDLError.m
index 7e5a0e95b..f72608a31 100644
--- a/SmartDeviceLink/SDLError.m
+++ b/SmartDeviceLink/SDLError.m
@@ -328,6 +328,12 @@ SDLErrorDomain *const SDLErrorDomainRPCStore = @"com.sdl.rpcStore.error";
                                  userInfo:nil];
 }
 
++ (NSException *)sdl_invalidSelectorExceptionWithSelector:(SEL)selector {
+    return [NSException exceptionWithName:@"com.sdl.systemCapabilityManager.selectorException"
+                                   reason:[NSString stringWithFormat:@"Capability observation selector: %@ does not match possible selectors, which must have either 0 or 1 parameters", NSStringFromSelector(selector)]
+                                 userInfo:nil];
+}
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/SmartDeviceLink/SDLLifecycleManager.m b/SmartDeviceLink/SDLLifecycleManager.m
index 0c3b257ab..7ba94a6f7 100644
--- a/SmartDeviceLink/SDLLifecycleManager.m
+++ b/SmartDeviceLink/SDLLifecycleManager.m
@@ -385,6 +385,7 @@ SDLLifecycleState *const SDLLifecycleStateReady = @"Ready";
     dispatch_group_enter(managerGroup);
     SDLLogD(@"Setting up assistant managers");
     [self.lockScreenManager start];
+    [self.systemCapabilityManager start];
 
     dispatch_group_enter(managerGroup);
     [self.fileManager startWithCompletionHandler:^(BOOL success, NSError *_Nullable error) {
diff --git a/SmartDeviceLink/SDLSystemCapabilityManager.h b/SmartDeviceLink/SDLSystemCapabilityManager.h
index 11e31a1c2..38030365a 100644
--- a/SmartDeviceLink/SDLSystemCapabilityManager.h
+++ b/SmartDeviceLink/SDLSystemCapabilityManager.h
@@ -24,6 +24,7 @@
 @class SDLPresetBankCapabilities;
 @class SDLRemoteControlCapabilities;
 @class SDLSoftButtonCapabilities;
+@class SDLSystemCapability;
 @class SDLSystemCapabilityManager;
 @class SDLVideoStreamingCapability;
 
@@ -31,7 +32,6 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-
 /**
  *  A completion handler called after a request for the capability type is returned from the remote system.
  *
@@ -40,10 +40,24 @@ NS_ASSUME_NONNULL_BEGIN
  */
 typedef void (^SDLUpdateCapabilityHandler)(NSError * _Nullable error, SDLSystemCapabilityManager *systemCapabilityManager);
 
+/**
+ An observer block for whenever a subscription is called.
+
+ @param capability The capability that was updated.
+ */
+typedef void (^SDLCapabilityUpdateHandler)(SDLSystemCapability *capability);
 
+/**
+ A manager that handles updating and subscribing to SDL capabilities.
+ */
 @interface SDLSystemCapabilityManager : NSObject
 
 /**
+ YES if subscriptions are available on the connected head unit. If NO, calls to `subscribeToCapabilityType:withBlock` and `subscribeToCapabilityType:withObserver:selector` will fail.
+ */
+@property (assign, nonatomic, readonly) BOOL supportsSubscriptions;
+
+/**
  * @see SDLDisplayCapabilities
  *
  * Optional
@@ -134,59 +148,64 @@ typedef void (^SDLUpdateCapabilityHandler)(NSError * _Nullable error, SDLSystemC
 @property (nullable, strong, nonatomic, readonly) SDLAppServicesCapabilities *appServicesCapabilities;
 
 /**
- * If returned, the platform supports navigation
- *
- * @see SDLNavigationCapability
- *
- * Optional
+ If returned, the platform supports navigation
+
+ @see SDLNavigationCapability
+
+ Optional
  */
 @property (nullable, strong, nonatomic, readonly) SDLNavigationCapability *navigationCapability;
 
 /**
- * If returned, the platform supports making phone calls
- *
- * @see SDLPhoneCapability
- *
- * Optional
+ If returned, the platform supports making phone calls
+
+ @see SDLPhoneCapability
+
+ Optional
  */
 @property (nullable, strong, nonatomic, readonly) SDLPhoneCapability *phoneCapability;
 
 /**
- * If returned, the platform supports video streaming
- *
- * @see SDLVideoStreamingCapability
- *
- * Optional
+ If returned, the platform supports video streaming
+
+ @see SDLVideoStreamingCapability
+
+ Optional
  */
 @property (nullable, strong, nonatomic, readonly) SDLVideoStreamingCapability *videoStreamingCapability;
 
 /**
- * If returned, the platform supports remote control capabilities
- *
- * @see SDLRemoteControlCapabilities
- *
- * Optional
+ If returned, the platform supports remote control capabilities
+
+ @see SDLRemoteControlCapabilities
+
+ Optional
  */
 @property (nullable, strong, nonatomic, readonly) SDLRemoteControlCapabilities *remoteControlCapability;
 
 /**
- *  Init is unavailable. Dependencies must be injected using initWithConnectionManager:
- *
- *  @return nil
+ Init is unavailable. Dependencies must be injected using initWithConnectionManager:
+
+ @return nil
  */
 - (instancetype)init NS_UNAVAILABLE;
 
 /**
- *  Creates a new system capability manager with a specified connection manager
- *
- *  @param manager A connection manager to use to forward on RPCs
- *
- *  @return An instance of SDLSystemCapabilityManager
+ Creates a new system capability manager with a specified connection manager
+
+ @param manager A connection manager to use to forward on RPCs
+
+ @return An instance of SDLSystemCapabilityManager
  */
 - (instancetype)initWithConnectionManager:(id<SDLConnectionManagerType>)manager NS_DESIGNATED_INITIALIZER;
 
 /**
- *  Stops the manager. This method is used internally.
+ Starts the manager. This method is used internally.
+ */
+- (void)start;
+
+/**
+ Stops the manager. This method is used internally.
  */
 - (void)stop;
 
@@ -198,6 +217,37 @@ typedef void (^SDLUpdateCapabilityHandler)(NSError * _Nullable error, SDLSystemC
  */
 - (void)updateCapabilityType:(SDLSystemCapabilityType)type completionHandler:(SDLUpdateCapabilityHandler)handler;
 
+/**
+ Subscribe to a particular capability type using a block callback
+
+ @param type The type of capability to subscribe to
+ @param block The block to be called when the capability is updated
+ @return An object that can be used to unsubscribe the block using unsubscribeFromCapabilityType:withObserver: by passing it in the observer callback, or nil if subscriptions aren't available on this head unit
+ */
+- (nullable id<NSObject>)subscribeToCapabilityType:(SDLSystemCapabilityType)type usingBlock:(SDLCapabilityUpdateHandler)block;
+
+/**
+ * Subscribe to a particular capability type with a selector callback. The selector supports the following parameters:
+ *
+ * 1. No parameters e.g. `- (void)phoneCapabilityUpdated;`
+ * 2. One `SDLSystemCapability *` parameter e.g. `- (void)phoneCapabilityUpdated:(SDLSystemCapability *)capability`
+ *
+ * This method will be called immediately with the current value and called every time the value is updated on RPC v5.1.0+ systems (`supportsSubscriptions == YES`). If this method is called on a sub-v5.1.0 system (`supportsSubscriptions == NO`), the method will return `NO` and the selector will never be called.
+ *
+ * @param type The type of the system capability to subscribe to
+ * @param observer The object that will have `selector` called whenever the capability is updated
+ * @param selector The selector on `observer` that will be called whenever the capability is updated
+ * @return Whether or not the subscription succeeded. `NO` if the connected system doesn't support capability subscriptions, or if the `selector` doesn't support the correct parameters (see above)
+ */
+- (BOOL)subscribeToCapabilityType:(SDLSystemCapabilityType)type withObserver:(id)observer selector:(SEL)selector;
+
+/**
+ * Unsubscribe from a particular capability type. If it was subscribed with a block, the return value should be passed to the `observer` to unsubscribe the block. If it was subscribed with a selector, the `observer` object should be passed to unsubscribe the object selector.
+ *
+ * @param type The type of the system capability to unsubscribe from
+ * @param observer The object that will be unsubscribed. If a block was subscribed, the return value should be passed. If a selector was subscribed, the observer object should be passed.
+ */
+- (void)unsubscribeFromCapabilityType:(SDLSystemCapabilityType)type withObserver:(id)observer;
 
 @end
 
diff --git a/SmartDeviceLink/SDLSystemCapabilityManager.m b/SmartDeviceLink/SDLSystemCapabilityManager.m
index 0a48ce71f..82d7c8c82 100644
--- a/SmartDeviceLink/SDLSystemCapabilityManager.m
+++ b/SmartDeviceLink/SDLSystemCapabilityManager.m
@@ -12,19 +12,24 @@
 #import "SDLAppServiceRecord.h"
 #import "SDLAppServicesCapabilities.h"
 #import "SDLConnectionManagerType.h"
+#import "SDLError.h"
 #import "SDLGenericResponse.h"
 #import "SDLGetSystemCapability.h"
 #import "SDLGetSystemCapabilityResponse.h"
 #import "SDLGlobals.h"
 #import "SDLLogMacros.h"
+#import "SDLNavigationCapability.h"
 #import "SDLNotificationConstants.h"
 #import "SDLOnHMIStatus.h"
 #import "SDLOnSystemCapabilityUpdated.h"
+#import "SDLPhoneCapability.h"
 #import "SDLRegisterAppInterfaceResponse.h"
+#import "SDLRemoteControlCapabilities.h"
 #import "SDLRPCNotificationNotification.h"
 #import "SDLRPCResponseNotification.h"
 #import "SDLSetDisplayLayoutResponse.h"
 #import "SDLSystemCapability.h"
+#import "SDLSystemCapabilityObserver.h"
 #import "SDLVersion.h"
 #import "SDLVideoStreamingCapability.h"
 
@@ -55,6 +60,11 @@ typedef NSString * SDLServiceID;
 
 @property (nullable, strong, nonatomic) NSMutableDictionary<SDLServiceID, SDLAppServiceCapability *> *appServicesCapabilitiesDictionary;
 
+@property (assign, nonatomic, readwrite) BOOL supportsSubscriptions;
+@property (strong, nonatomic) NSMutableDictionary<SDLSystemCapabilityType, NSMutableArray<SDLSystemCapabilityObserver *> *> *capabilityObservers;
+
+@property (nullable, strong, nonatomic) SDLSystemCapability *lastReceivedCapability;
+
 @property (assign, nonatomic) BOOL isFirstHMILevelFull;
 
 @end
@@ -73,11 +83,24 @@ typedef NSString * SDLServiceID;
     _isFirstHMILevelFull = NO;
     _appServicesCapabilitiesDictionary = [NSMutableDictionary dictionary];
 
+    _capabilityObservers = [NSMutableDictionary dictionary];
+    for (SDLSystemCapabilityType capabilityType in [self.class sdl_systemCapabilityTypes]) {
+        _capabilityObservers[capabilityType] = [NSMutableArray array];
+    }
+
     [self sdl_registerForNotifications];    
 
     return self;
 }
 
+- (void)start {
+    SDLVersion *onSystemCapabilityNotificationRPCVersion = [SDLVersion versionWithString:@"5.1.0"];
+    SDLVersion *headUnitRPCVersion = SDLGlobals.sharedGlobals.rpcVersion;
+    if ([headUnitRPCVersion isGreaterThanOrEqualToVersion:onSystemCapabilityNotificationRPCVersion]) {
+        _supportsSubscriptions = YES;
+    }
+}
+
 /**
  *  Resets the capabilities when a transport session is closed.
  */
@@ -100,6 +123,11 @@ typedef NSString * SDLServiceID;
     _remoteControlCapability = nil;
     _appServicesCapabilitiesDictionary = [NSMutableDictionary dictionary];
 
+    _supportsSubscriptions = NO;
+    for (SDLSystemCapabilityType capabilityType in [self.class sdl_systemCapabilityTypes]) {
+        _capabilityObservers[capabilityType] = [NSMutableArray array];
+    }
+
     _isFirstHMILevelFull = NO;
 }
 
@@ -120,6 +148,7 @@ typedef NSString * SDLServiceID;
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sdl_registerResponse:) name:SDLDidReceiveRegisterAppInterfaceResponse object:nil];
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sdl_displayLayoutResponse:) name:SDLDidReceiveSetDisplayLayoutResponse object:nil];
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sdl_systemCapabilityUpdatedNotification:) name:SDLDidReceiveSystemCapabilityUpdatedNotification object:nil];
+    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sdl_systemCapabilityResponseNotification:) name:SDLDidReceiveGetSystemCapabilitiesResponse object:nil];
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sdl_hmiStatusNotification:) name:SDLDidChangeHMIStatusNotification object:nil];
 }
 
@@ -171,6 +200,16 @@ typedef NSString * SDLServiceID;
 }
 
 /**
+ Called with a `GetSystemCapabilityResponse` notification is received from core. The updated system capability is saved.
+
+ @param notification The `GetSystemCapabilityResponse` notification received from Core
+ */
+- (void)sdl_systemCapabilityResponseNotification:(SDLRPCResponseNotification *)notification {
+    SDLGetSystemCapabilityResponse *systemCapabilityResponse = (SDLGetSystemCapabilityResponse *)notification.response;
+    [self sdl_saveSystemCapability:systemCapabilityResponse.systemCapability completionHandler:nil];
+}
+
+/**
  *  Called when an `OnHMIStatus` notification is received from Core. The first time the `hmiLevel` is `FULL` attempt to subscribe to system capabilty updates.
  *
  *  @param notification The `OnHMIStatus` notification received from Core
@@ -188,9 +227,7 @@ typedef NSString * SDLServiceID;
 #pragma mark - System Capabilities
 
 - (void)updateCapabilityType:(SDLSystemCapabilityType)type completionHandler:(SDLUpdateCapabilityHandler)handler {
-    SDLVersion *onSystemCapabilityNotificationRPCVersion = [SDLVersion versionWithString:@"5.1.0"];
-    SDLVersion *headUnitRPCVersion = SDLGlobals.sharedGlobals.rpcVersion;
-    if ([headUnitRPCVersion isGreaterThanOrEqualToVersion:onSystemCapabilityNotificationRPCVersion]) {
+    if (self.supportsSubscriptions) {
         // Just return the cached data because we get `onSystemCapability` callbacks
         handler(nil, self);
     } else {
@@ -215,9 +252,7 @@ typedef NSString * SDLServiceID;
 - (void)sdl_subscribeToSystemCapabilityUpdates {
     for (SDLSystemCapabilityType type in [self.class sdl_systemCapabilityTypes]) {
         SDLGetSystemCapability *getSystemCapability = [[SDLGetSystemCapability alloc] initWithType:type];
-        SDLVersion *onSystemCapabilityNotificationRPCVersion = [SDLVersion versionWithString:@"5.1.0"];
-        SDLVersion *headUnitRPCVersion = SDLGlobals.sharedGlobals.rpcVersion;
-        if ([headUnitRPCVersion isGreaterThanOrEqualToVersion:onSystemCapabilityNotificationRPCVersion]) {
+        if (self.supportsSubscriptions) {
             getSystemCapability.subscribe = @YES;
         }
 
@@ -231,47 +266,87 @@ typedef NSString * SDLServiceID;
  *  @param getSystemCapability The `GetSystemCapability` request to send
  */
 - (void)sdl_sendGetSystemCapability:(SDLGetSystemCapability *)getSystemCapability completionHandler:(nullable SDLUpdateCapabilityHandler)handler {
+    __weak typeof(self) weakSelf = self;
     [self.connectionManager sendConnectionRequest:getSystemCapability withResponseHandler:^(__kindof SDLRPCRequest * _Nullable request, __kindof SDLRPCResponse * _Nullable response, NSError * _Nullable error) {
         if (error != nil) {
             // An error is returned if the request was unsuccessful or if a Generic Response was returned
             if (handler == nil) { return; }
-            handler(error, self);
+            handler(error, weakSelf);
             return;
         }
 
         SDLGetSystemCapabilityResponse *getSystemCapabilityResponse = (SDLGetSystemCapabilityResponse *)response;
-        if (!getSystemCapabilityResponse.success.boolValue) { return; }
-        [self sdl_saveSystemCapability:getSystemCapabilityResponse.systemCapability completionHandler:handler];
+        [weakSelf sdl_saveSystemCapability:getSystemCapabilityResponse.systemCapability completionHandler:handler];
     }];
 }
 
 /**
- *  Saves a system capability. All system capabilities will update with the full object except for app services. For app services only the updated app service capabilities will be included in the `SystemCapability` sent from Core. The cached `appServicesCapabilities` will be updated with the new `appService` data.
- *
- *  @param systemCapability The system capability
+ Saves a system capability. All system capabilities will update with the full object except for app services. For app services only the updated app service capabilities will be included in the `SystemCapability` sent from Core. The cached `appServicesCapabilities` will be updated with the new `appService` data.
+
+ @param systemCapability The system capability to be saved
+ @param handler The handler to be called when the save completes
+ @return Whether or not the save occurred. This can be `NO` if the new system capability is equivalent to the old capability.
  */
-- (void)sdl_saveSystemCapability:(SDLSystemCapability *)systemCapability completionHandler:(nullable SDLUpdateCapabilityHandler)handler {
+- (BOOL)sdl_saveSystemCapability:(SDLSystemCapability *)systemCapability completionHandler:(nullable SDLUpdateCapabilityHandler)handler {
+    if ([self.lastReceivedCapability isEqual:systemCapability]) {
+        return [self sdl_callSaveHandlerForCapability:systemCapability andReturnWithValue:NO handler:handler];
+    }
+    self.lastReceivedCapability = systemCapability;
+
     SDLSystemCapabilityType systemCapabilityType = systemCapability.systemCapabilityType;
 
     if ([systemCapabilityType isEqualToEnum:SDLSystemCapabilityTypePhoneCall]) {
+        if ([self.phoneCapability isEqual:systemCapability.phoneCapability]) { return [self sdl_callSaveHandlerForCapability:systemCapability andReturnWithValue:NO handler:handler]; }
         self.phoneCapability = systemCapability.phoneCapability;
     } else if ([systemCapabilityType isEqualToEnum:SDLSystemCapabilityTypeNavigation]) {
+        if ([self.navigationCapability isEqual:systemCapability.navigationCapability]) { return [self sdl_callSaveHandlerForCapability:systemCapability andReturnWithValue:NO handler:handler]; }
         self.navigationCapability = systemCapability.navigationCapability;
     } else if ([systemCapabilityType isEqualToEnum:SDLSystemCapabilityTypeRemoteControl]) {
+        if ([self.remoteControlCapability isEqual:systemCapability.remoteControlCapability]) { return [self sdl_callSaveHandlerForCapability:systemCapability andReturnWithValue:NO handler:handler]; }
         self.remoteControlCapability = systemCapability.remoteControlCapability;
     } else if ([systemCapabilityType isEqualToEnum:SDLSystemCapabilityTypeVideoStreaming]) {
+        if ([self.videoStreamingCapability isEqual:systemCapability.videoStreamingCapability]) { return [self sdl_callSaveHandlerForCapability:systemCapability andReturnWithValue:NO handler:handler]; }
         self.videoStreamingCapability = systemCapability.videoStreamingCapability;
     } else if ([systemCapabilityType isEqualToEnum:SDLSystemCapabilityTypeAppServices]) {
         [self sdl_saveAppServicesCapabilitiesUpdate:systemCapability.appServicesCapabilities];
+        systemCapability = [[SDLSystemCapability alloc] initWithAppServicesCapabilities:self.appServicesCapabilities];
     } else {
         SDLLogW(@"Received response for unknown System Capability Type: %@", systemCapabilityType);
-        return;
+        return NO;
     }
 
     SDLLogD(@"Updated system capability manager with new data: %@", systemCapability);
 
-    if (handler == nil) { return; }
+    return [self sdl_callSaveHandlerForCapability:systemCapability andReturnWithValue:YES handler:handler];
+}
+
+- (BOOL)sdl_callSaveHandlerForCapability:(SDLSystemCapability *)capability andReturnWithValue:(BOOL)value handler:(nullable SDLUpdateCapabilityHandler)handler {
+    for (SDLSystemCapabilityObserver *observer in self.capabilityObservers[capability.systemCapabilityType]) {
+        if (observer.block != nil) {
+            observer.block(capability);
+        } else {
+            NSUInteger numberOfParametersInSelector = [NSStringFromSelector(observer.selector) componentsSeparatedByString:@":"].count - 1;
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Warc-performSelector-leaks"
+            if (numberOfParametersInSelector == 0) {
+                if ([observer.observer respondsToSelector:observer.selector]) {
+                    [observer.observer performSelector:observer.selector];
+                }
+            } else if (numberOfParametersInSelector == 1) {
+                if ([observer.observer respondsToSelector:observer.selector]) {
+                    [observer.observer performSelector:observer.selector withObject:capability];
+                }
+            } else {
+                @throw [NSException sdl_invalidSelectorExceptionWithSelector:observer.selector];
+            }
+#pragma clang diagnostic pop
+        }
+    }
+
+    if (handler == nil) { return value; }
     handler(nil, self);
+
+    return value;
 }
 
 - (void)sdl_saveAppServicesCapabilitiesUpdate:(SDLAppServicesCapabilities *)newCapabilities {
@@ -288,6 +363,38 @@ typedef NSString * SDLServiceID;
     }
 }
 
+#pragma mark - Subscriptions
+
+- (nullable id<NSObject>)subscribeToCapabilityType:(SDLSystemCapabilityType)type usingBlock:(SDLCapabilityUpdateHandler)block {
+    if (!self.supportsSubscriptions) { return nil; }
+
+    SDLSystemCapabilityObserver *observerObject = [[SDLSystemCapabilityObserver alloc] initWithObserver:[[NSObject alloc] init] block:block];
+    [self.capabilityObservers[type] addObject:observerObject];
+
+    return observerObject.observer;
+}
+
+- (BOOL)subscribeToCapabilityType:(SDLSystemCapabilityType)type withObserver:(id<NSObject>)observer selector:(SEL)selector {
+    if (!self.supportsSubscriptions) { return NO; }
+
+    NSUInteger numberOfParametersInSelector = [NSStringFromSelector(selector) componentsSeparatedByString:@":"].count - 1;
+    if (numberOfParametersInSelector > 1) { return NO; }
+
+    SDLSystemCapabilityObserver *observerObject = [[SDLSystemCapabilityObserver alloc] initWithObserver:observer selector:selector];
+    [self.capabilityObservers[type] addObject:observerObject];
+
+    return observerObject.observer;
+}
+
+- (void)unsubscribeFromCapabilityType:(SDLSystemCapabilityType)type withObserver:(id)observer {
+    for (SDLSystemCapabilityObserver *capabilityObserver in self.capabilityObservers[type]) {
+        if ([observer isEqual:capabilityObserver.observer]) {
+            [self.capabilityObservers[type] removeObject:capabilityObserver];
+            break;
+        }
+    }
+}
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/SmartDeviceLink/SDLSystemCapabilityObserver.h b/SmartDeviceLink/SDLSystemCapabilityObserver.h
new file mode 100644
index 000000000..f5450d60e
--- /dev/null
+++ b/SmartDeviceLink/SDLSystemCapabilityObserver.h
@@ -0,0 +1,57 @@
+//
+//  SDLSystemCapabilityObserver.h
+//  SmartDeviceLink
+//
+//  Created by Joel Fischer on 5/23/19.
+//  Copyright © 2019 smartdevicelink. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+@class SDLSystemCapability;
+
+NS_ASSUME_NONNULL_BEGIN
+
+typedef void (^SDLCapabilityUpdateHandler)(SDLSystemCapability *capability);
+
+/**
+ An observer object for SDLSystemCapabilityManager
+ */
+@interface SDLSystemCapabilityObserver : NSObject
+
+/**
+ The object that will be used to call the selector if available, and to unsubscribe this observer
+ */
+@property (strong, nonatomic) id<NSObject> observer;
+
+/**
+ A selector called when the observer is triggered
+ */
+@property (assign, nonatomic) SEL selector;
+
+/**
+ A block called when the observer is triggered
+ */
+@property (copy, nonatomic) SDLCapabilityUpdateHandler block;
+
+/**
+ Create an observer using an object and a selector on that object
+
+ @param observer The object to be called when the subscription triggers
+ @param selector The selector to be called when the subscription triggers
+ @return The observer
+ */
+- (instancetype)initWithObserver:(id<NSObject>)observer selector:(SEL)selector;
+
+/**
+ Create an observer using an object and a callback block
+
+ @param observer The object that can be used to unsubscribe the block
+ @param block The block that will be called when the subscription triggers
+ @return The observer
+ */
+- (instancetype)initWithObserver:(id<NSObject>)observer block:(SDLCapabilityUpdateHandler)block;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/SmartDeviceLink/SDLSystemCapabilityObserver.m b/SmartDeviceLink/SDLSystemCapabilityObserver.m
new file mode 100644
index 000000000..64832f1a7
--- /dev/null
+++ b/SmartDeviceLink/SDLSystemCapabilityObserver.m
@@ -0,0 +1,37 @@
+//
+//  SDLSystemCapabilityObserver.m
+//  SmartDeviceLink
+//
+//  Created by Joel Fischer on 5/23/19.
+//  Copyright © 2019 smartdevicelink. All rights reserved.
+//
+
+#import "SDLSystemCapabilityObserver.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@implementation SDLSystemCapabilityObserver
+
+- (instancetype)initWithObserver:(id<NSObject>)observer selector:(SEL)selector {
+    self = [super init];
+    if (!self) { return nil; }
+
+    _observer = observer;
+    _selector = selector;
+
+    return self;
+}
+
+- (instancetype)initWithObserver:(id<NSObject>)observer block:(SDLCapabilityUpdateHandler)block {
+    self = [super init];
+    if (!self) { return nil; }
+
+    _observer = observer;
+    _block = block;
+
+    return self;
+}
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/SmartDeviceLinkTests/DevAPISpecs/TestSystemCapabilityObserver.h b/SmartDeviceLinkTests/DevAPISpecs/TestSystemCapabilityObserver.h
new file mode 100644
index 000000000..0e6c8bcbb
--- /dev/null
+++ b/SmartDeviceLinkTests/DevAPISpecs/TestSystemCapabilityObserver.h
@@ -0,0 +1,24 @@
+//
+//  TestSystemCapabilityObserver.h
+//  SmartDeviceLinkTests
+//
+//  Created by Joel Fischer on 5/23/19.
+//  Copyright © 2019 smartdevicelink. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+@class SDLSystemCapabilityManager;
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface TestSystemCapabilityObserver : NSObject
+
+@property (assign, nonatomic) NSUInteger selectorCalledCount;
+
+- (void)capabilityUpdated;
+- (void)capabilityUpdatedWithNotification:(SDLSystemCapabilityManager *)capabilityManager;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/SmartDeviceLinkTests/DevAPISpecs/TestSystemCapabilityObserver.m b/SmartDeviceLinkTests/DevAPISpecs/TestSystemCapabilityObserver.m
new file mode 100644
index 000000000..5366b0884
--- /dev/null
+++ b/SmartDeviceLinkTests/DevAPISpecs/TestSystemCapabilityObserver.m
@@ -0,0 +1,30 @@
+//
+//  TestSystemCapabilityObserver.m
+//  SmartDeviceLinkTests
+//
+//  Created by Joel Fischer on 5/23/19.
+//  Copyright © 2019 smartdevicelink. All rights reserved.
+//
+
+#import "TestSystemCapabilityObserver.h"
+
+@implementation TestSystemCapabilityObserver
+
+- (instancetype)init {
+    self = [super init];
+    if (!self) { return nil; }
+
+    _selectorCalledCount = 0;
+
+    return self;
+}
+
+- (void)capabilityUpdated {
+    self.selectorCalledCount++;
+}
+
+- (void)capabilityUpdatedWithNotification:(SDLSystemCapabilityManager *)capabilityManager {
+    self.selectorCalledCount++;
+}
+
+@end
diff --git a/SmartDeviceLinkTests/SDLSystemCapabilityManagerSpec.m b/SmartDeviceLinkTests/SDLSystemCapabilityManagerSpec.m
index 109b8ea2d..4fc9a6547 100644
--- a/SmartDeviceLinkTests/SDLSystemCapabilityManagerSpec.m
+++ b/SmartDeviceLinkTests/SDLSystemCapabilityManagerSpec.m
@@ -29,6 +29,14 @@
 #import "SDLSystemCapabilityManager.h"
 #import "SDLVideoStreamingCapability.h"
 #import "TestConnectionManager.h"
+#import "TestSystemCapabilityObserver.h"
+
+
+@interface SDLSystemCapabilityManager ()
+
+@property (assign, nonatomic, readwrite) BOOL supportsSubscriptions;
+
+@end
 
 
 QuickSpecBegin(SDLSystemCapabilityManagerSpec)
@@ -181,7 +189,7 @@ describe(@"System capability manager", ^{
         });
     });
 
-    context(@"When notified of a Set Display Layout Response", ^ {
+    context(@"When notified of a SetDisplayLayout Response", ^ {
         __block SDLSetDisplayLayoutResponse *testSetDisplayLayoutResponse = nil;
         __block SDLDisplayCapabilities *testDisplayCapabilities = nil;
         __block NSArray<SDLSoftButtonCapabilities *> *testSoftButtonCapabilities = nil;
@@ -216,7 +224,7 @@ describe(@"System capability manager", ^{
             testSetDisplayLayoutResponse.presetBankCapabilities = testPresetBankCapabilities;
         });
 
-        describe(@"If the Set Display Layout request fails", ^{
+        describe(@"If the SetDisplayLayout request fails", ^{
             beforeEach(^{
                 testSetDisplayLayoutResponse.success = @NO;
                 SDLRPCResponseNotification *notification = [[SDLRPCResponseNotification alloc] initWithName:SDLDidReceiveSetDisplayLayoutResponse object:self rpcResponse:testSetDisplayLayoutResponse];
@@ -231,7 +239,7 @@ describe(@"System capability manager", ^{
             });
         });
 
-        describe(@"If the Set Display Layout request succeeds", ^{
+        describe(@"If the SetDisplayLayout request succeeds", ^{
             beforeEach(^{
                 testSetDisplayLayoutResponse.success = @YES;
                 SDLRPCResponseNotification *notification = [[SDLRPCResponseNotification alloc] initWithName:SDLDidReceiveSetDisplayLayoutResponse object:self rpcResponse:testSetDisplayLayoutResponse];
@@ -263,8 +271,8 @@ describe(@"System capability manager", ^{
         });
     });
 
-    context(@"When sending a Get System Capability request", ^{
-        __block SDLGetSystemCapabilityResponse *testGetSystemCapabilityResponse;
+    context(@"When sending a GetSystemCapability request", ^{
+        __block SDLGetSystemCapabilityResponse *testGetSystemCapabilityResponse = nil;
         __block SDLPhoneCapability *testPhoneCapability = nil;
 
         beforeEach(^{
@@ -347,6 +355,7 @@ describe(@"System capability manager", ^{
             SDLSystemCapability *newCapability = [[SDLSystemCapability alloc] initWithPhoneCapability:phoneCapability];
             SDLOnSystemCapabilityUpdated *update = [[SDLOnSystemCapabilityUpdated alloc] initWithSystemCapability:newCapability];
             SDLRPCNotificationNotification *notification = [[SDLRPCNotificationNotification alloc] initWithName:SDLDidReceiveSystemCapabilityUpdatedNotification object:nil rpcNotification:update];
+
             [[NSNotificationCenter defaultCenter] postNotification:notification];
         });
 
@@ -355,6 +364,118 @@ describe(@"System capability manager", ^{
         });
     });
 
+    describe(@"subscribing to capability types", ^{
+        __block TestSystemCapabilityObserver *phoneObserver = nil;
+        __block TestSystemCapabilityObserver *navigationObserver = nil;
+
+        __block NSUInteger blockObserverTriggeredCount = 0;
+
+        beforeEach(^{
+            blockObserverTriggeredCount = 0;
+            testSystemCapabilityManager.supportsSubscriptions = YES;
+
+            phoneObserver = [[TestSystemCapabilityObserver alloc] init];
+            [testSystemCapabilityManager subscribeToCapabilityType:SDLSystemCapabilityTypePhoneCall withObserver:phoneObserver selector:@selector(capabilityUpdatedWithNotification:)];
+            navigationObserver = [[TestSystemCapabilityObserver alloc] init];
+            [testSystemCapabilityManager subscribeToCapabilityType:SDLSystemCapabilityTypeNavigation withObserver:navigationObserver selector:@selector(capabilityUpdatedWithNotification:)];
+        });
+
+        describe(@"when observers aren't supported", ^{
+            __block BOOL observationSuccess = NO;
+
+            beforeEach(^{
+                testSystemCapabilityManager.supportsSubscriptions = NO;
+
+                observationSuccess = [testSystemCapabilityManager subscribeToCapabilityType:SDLSystemCapabilityTypePhoneCall withObserver:phoneObserver selector:@selector(capabilityUpdatedWithNotification:)];
+            });
+
+            it(@"should fail to subscribe", ^{
+                expect(observationSuccess).to(beFalse());
+            });
+        });
+
+        context(@"from a GetSystemCapabilitiesResponse", ^{
+            __block id blockObserver = nil;
+
+            beforeEach(^{
+                blockObserver = [testSystemCapabilityManager subscribeToCapabilityType:SDLSystemCapabilityTypePhoneCall usingBlock:^(SDLSystemCapability * _Nonnull systemCapability) {
+                    blockObserverTriggeredCount++;
+                }];
+
+                SDLGetSystemCapabilityResponse *testResponse = [[SDLGetSystemCapabilityResponse alloc] init];
+                testResponse.systemCapability = [[SDLSystemCapability alloc] initWithPhoneCapability:[[SDLPhoneCapability alloc] initWithDialNumber:YES]];
+                SDLRPCResponseNotification *notification = [[SDLRPCResponseNotification alloc] initWithName:SDLDidReceiveGetSystemCapabilitiesResponse object:nil rpcResponse:testResponse];
+
+                [[NSNotificationCenter defaultCenter] postNotification:notification];
+            });
+
+            it(@"should notify subscribers of the new data", ^{
+                expect(phoneObserver.selectorCalledCount).toEventually(equal(1));
+                expect(blockObserverTriggeredCount).toEventually(equal(1));
+                expect(navigationObserver.selectorCalledCount).toEventually(equal(0));
+            });
+
+            describe(@"unsubscribing", ^{
+                beforeEach(^{
+                    [testSystemCapabilityManager unsubscribeFromCapabilityType:SDLSystemCapabilityTypePhoneCall withObserver:phoneObserver];
+                    [testSystemCapabilityManager unsubscribeFromCapabilityType:SDLSystemCapabilityTypePhoneCall withObserver:blockObserver];
+
+                    SDLGetSystemCapabilityResponse *testResponse = [[SDLGetSystemCapabilityResponse alloc] init];
+                    testResponse.systemCapability = [[SDLSystemCapability alloc] initWithPhoneCapability:[[SDLPhoneCapability alloc] initWithDialNumber:YES]];
+                    SDLRPCResponseNotification *notification = [[SDLRPCResponseNotification alloc] initWithName:SDLDidReceiveGetSystemCapabilitiesResponse object:nil rpcResponse:testResponse];
+
+                    [[NSNotificationCenter defaultCenter] postNotification:notification];
+                });
+
+                it(@"should not notify the subscriber of the new data", ^{
+                    expect(phoneObserver.selectorCalledCount).toEventually(equal(1)); // No change from above
+                    expect(blockObserverTriggeredCount).toEventually(equal(1));
+                    expect(navigationObserver.selectorCalledCount).toEventually(equal(0));
+                });
+            });
+        });
+
+        context(@"from an OnSystemCapabilities notification", ^{
+            __block id blockObserver = nil;
+
+            beforeEach(^{
+                blockObserver = [testSystemCapabilityManager subscribeToCapabilityType:SDLSystemCapabilityTypePhoneCall usingBlock:^(SDLSystemCapability * _Nonnull systemCapability) {
+                    blockObserverTriggeredCount++;
+                }];
+
+                SDLOnSystemCapabilityUpdated *testNotification = [[SDLOnSystemCapabilityUpdated alloc] initWithSystemCapability:[[SDLSystemCapability alloc] initWithPhoneCapability:[[SDLPhoneCapability alloc] initWithDialNumber:YES]]];
+                SDLRPCNotificationNotification *notification = [[SDLRPCNotificationNotification alloc] initWithName:SDLDidReceiveSystemCapabilityUpdatedNotification object:nil rpcNotification:testNotification];
+
+                [[NSNotificationCenter defaultCenter] postNotification:notification];
+            });
+
+            it(@"should notify subscribers of the new data", ^{
+                expect(phoneObserver.selectorCalledCount).toEventually(equal(1));
+                expect(blockObserverTriggeredCount).toEventually(equal(1));
+                expect(navigationObserver.selectorCalledCount).toEventually(equal(0));
+            });
+
+            describe(@"unsubscribing", ^{
+                beforeEach(^{
+                    [testSystemCapabilityManager unsubscribeFromCapabilityType:SDLSystemCapabilityTypePhoneCall withObserver:phoneObserver];
+                    [testSystemCapabilityManager unsubscribeFromCapabilityType:SDLSystemCapabilityTypePhoneCall withObserver:blockObserver];
+
+                    SDLGetSystemCapabilityResponse *testResponse = [[SDLGetSystemCapabilityResponse alloc] init];
+                    testResponse.systemCapability = [[SDLSystemCapability alloc] initWithPhoneCapability:[[SDLPhoneCapability alloc] initWithDialNumber:YES]];
+                    SDLRPCResponseNotification *notification = [[SDLRPCResponseNotification alloc] initWithName:SDLDidReceiveGetSystemCapabilitiesResponse object:nil rpcResponse:testResponse];
+
+                    [[NSNotificationCenter defaultCenter] postNotification:notification];
+                });
+
+                it(@"should not notify the subscriber of the new data", ^{
+                    expect(phoneObserver.selectorCalledCount).toEventually(equal(1)); // No change from above
+                    expect(blockObserverTriggeredCount).toEventually(equal(1));
+                    expect(navigationObserver.selectorCalledCount).toEventually(equal(0));
+                });
+            });
+        });
+    });
+
     describe(@"merging app services capability changes", ^{
         __block SDLAppServicesCapabilities *baseAppServices = nil;
         __block SDLAppServiceCapability *deleteCapability = nil;