Added unit test

src/darwin/Framework/CHIP/MTRDefines_Internal.h

@@ -150,3 +150,7 @@ typedef struct {} variable_hidden_by_mtr_hide;
         }                                                                                                                  \
     }
 #endif
+
+#ifndef YES_NO
+#define YES_NO(x) ((x) ? @"YES" : @"NO")
+#endif

src/darwin/Framework/CHIP/MTRDeviceController.mm

@@ -1779,6 +1779,11 @@ - (void)setDeviceControllerDelegate:(id<MTRDeviceControllerDelegate>)delegate qu
 {
     @synchronized(self) {
         if (_strongDelegateForSetDelegateAPI) {
+            if (_strongDelegateForSetDelegateAPI == delegate) {
+                MTR_LOG("%@ setDeviceControllerDelegate: delegate %p is already set", self, delegate);
+                return;
+            }
+
             MTR_LOG("%@ setDeviceControllerDelegate: replacing %p with %p", self, _strongDelegateForSetDelegateAPI, delegate);
             [self removeDeviceControllerDelegate:_strongDelegateForSetDelegateAPI];
         }
@@ -1799,6 +1804,10 @@ - (void)addDeviceControllerDelegate:(id<MTRDeviceControllerDelegate>)delegate qu
 - (void)removeDeviceControllerDelegate:(id<MTRDeviceControllerDelegate>)delegate
 {
     @synchronized(self) {
+        if (_strongDelegateForSetDelegateAPI == delegate) {
+            _strongDelegateForSetDelegateAPI = nil;
+        }
+
         __block MTRDeviceControllerDelegateInfo * delegateInfoToRemove = nil;
         [self _iterateDelegateInfoWithBlock:^(MTRDeviceControllerDelegateInfo * delegateInfo) {
             if (delegateInfo.delegate == delegate) {
@@ -1865,6 +1874,13 @@ - (void)_callDelegatesWithBlock:(void (^_Nullable)(id<MTRDeviceControllerDelegat
     MTR_LOG("%@ %lu delegates called for %s", self, static_cast<unsigned long>(delegatesCalled), logString);
 }
 
+#if DEBUG
+- (NSUInteger)unitTestDelegateCount
+{
+    return [self _iterateDelegateInfoWithBlock:nil];
+}
+#endif
+
 - (void)controller:(MTRDeviceController *)controller statusUpdate:(MTRCommissioningStatus)status
 {
     [self _callDelegatesWithBlock:^(id<MTRDeviceControllerDelegate> delegate) {

src/darwin/Framework/CHIP/MTRError_Internal.h

@@ -26,10 +26,6 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-#ifndef YES_NO
-#define YES_NO(x) ((x) ? @"YES" : @"NO")
-#endif
-
 MTR_DIRECT_MEMBERS
 @interface MTRError : NSObject
 + (NSError *)errorWithCode:(MTRErrorCode)code;

src/darwin/Framework/CHIPTests/MTRPairingTests.m

@@ -18,9 +18,11 @@
 // module headers
 #import <Matter/Matter.h>
 
+#import "MTRDefines_Internal.h"
 #import "MTRErrorTestUtils.h"
 #import "MTRTestCase+ServerAppRunner.h"
 #import "MTRTestCase.h"
+#import "MTRTestDeclarations.h"
 #import "MTRTestKeys.h"
 #import "MTRTestStorage.h"
 
@@ -131,6 +133,42 @@ - (void)controller:(MTRDeviceController *)controller commissioningComplete:(NSEr
 
 @end
 
+@interface MTRPairingTestMonitoringControllerDelegate : NSObject <MTRDeviceControllerDelegate>
+@property(nonatomic, readonly) BOOL statusUpdateCalled;
+@property(nonatomic, readonly) BOOL commissioningSessionEstablishmentDoneCalled;
+@property(nonatomic, readonly) BOOL commissioningCompleteCalled;
+@property(nonatomic, readonly) BOOL readCommissioningInfoCalled;
+@end
+
+@implementation MTRPairingTestMonitoringControllerDelegate
+- (NSString *)description
+{
+    return [NSString stringWithFormat:@"<MTRPairingTestMonitoringControllerDelegate: %p statusUpdateCalled %@ commissioningSessionEstablishmentDoneCalled %@ commissioningCompleteCalled %@ readCommissioningInfoCalled %@>", self, YES_NO(_statusUpdateCalled), YES_NO(_commissioningSessionEstablishmentDoneCalled), YES_NO(_commissioningCompleteCalled), YES_NO(_readCommissioningInfoCalled)];
+}
+- (void)controller:(MTRDeviceController *)controller statusUpdate:(MTRCommissioningStatus)status
+{
+    _statusUpdateCalled = YES;
+}
+
+- (void)controller:(MTRDeviceController *)controller commissioningSessionEstablishmentDone:(NSError * _Nullable)error
+{
+    _commissioningSessionEstablishmentDoneCalled = YES;
+}
+
+- (void)controller:(MTRDeviceController *)controller
+    commissioningComplete:(NSError * _Nullable)error
+                   nodeID:(NSNumber * _Nullable)nodeID
+                  metrics:(MTRMetrics *)metrics
+{
+    _commissioningCompleteCalled = YES;
+}
+
+- (void)controller:(MTRDeviceController *)controller readCommissioningInfo:(MTRProductIdentity *)info
+{
+    _readCommissioningInfoCalled = YES;
+}
+@end
+
 @interface MTRPairingTests : MTRTestCase
 @property (nullable) MTRPairingTestControllerDelegate * controllerDelegate;
 @end
@@ -219,6 +257,19 @@ - (void)doPairingTestWithAttestationDelegate:(id<MTRDeviceAttestationDelegate>)a
     [sController setDeviceControllerDelegate:controllerDelegate queue:callbackQueue];
     self.controllerDelegate = controllerDelegate;
 
+    // Test that a monitoring delegate works
+    __auto_type * monitoringControllerDelegate = [[MTRPairingTestMonitoringControllerDelegate alloc] init];
+    [sController addDeviceControllerDelegate:monitoringControllerDelegate queue:callbackQueue];
+    XCTAssertEqual([sController unitTestDelegateCount], 2);
+
+    // Test that the addDeviceControllerDelegate delegate is held weakly by the controller
+    @autoreleasepool {
+        __auto_type * monitoringControllerDelegate = [[MTRPairingTestMonitoringControllerDelegate alloc] init];
+        [sController addDeviceControllerDelegate:monitoringControllerDelegate queue:callbackQueue];
+        XCTAssertEqual([sController unitTestDelegateCount], 3);
+    }
+    XCTAssertEqual([sController unitTestDelegateCount], 2);
+
     NSError * error;
     __auto_type * payload = [MTRSetupPayload setupPayloadWithOnboardingPayload:kOnboardingPayload error:&error];
     XCTAssertNotNil(payload);
@@ -229,6 +280,13 @@ - (void)doPairingTestWithAttestationDelegate:(id<MTRDeviceAttestationDelegate>)a
 
     [self waitForExpectations:@[ expectation ] timeout:kPairingTimeoutInSeconds];
     XCTAssertNil(controllerDelegate.commissioningCompleteError);
+
+    // Test that the monitoring delegate got all the callbacks
+    XCTAssertTrue(monitoringControllerDelegate.statusUpdateCalled);
+    XCTAssertTrue(monitoringControllerDelegate.commissioningSessionEstablishmentDoneCalled);
+    XCTAssertTrue(monitoringControllerDelegate.commissioningCompleteCalled);
+    XCTAssertTrue(monitoringControllerDelegate.readCommissioningInfoCalled);
+    [sController removeDeviceControllerDelegate:monitoringControllerDelegate];
 }
 
 - (void)test001_PairWithoutAttestationDelegate

src/darwin/Framework/CHIPTests/TestHelpers/MTRTestDeclarations.h

@@ -18,6 +18,9 @@
 #import <Foundation/Foundation.h>
 #import <Matter/Matter.h>
 
+// For MTRDeviceDataValueDictionary:
+#import "MTRDevice_Internal.h"
+
 NS_ASSUME_NONNULL_BEGIN
 
 #pragma mark - Declarations for internal methods
@@ -55,6 +58,7 @@ NS_ASSUME_NONNULL_BEGIN
 #ifdef DEBUG
 @interface MTRDeviceController (TestDebug)
 - (NSDictionary<NSNumber *, NSNumber *> *)unitTestGetDeviceAttributeCounts;
+- (NSUInteger)unitTestDelegateCount;
 @end
 
 @interface MTRBaseDevice (TestDebug)