FlipperClient tests on iOS

Summary:
This diff adds few tests for flipper client on iOS side. This tests are similar to the ones which exists in xplat but this tests the iOS side of flipper client.

Following tests are added

- connect , disconnect block called on plugin
- background plugin activated before init method
- crash getting suppressed

Reviewed By: jknoxville

Differential Revision: D13167637

fbshipit-source-id: 6c21d5cf2f08e7e3c17ecacbf3badfbde80fb5d1

iOS/FlipperKit/FlipperClient+Testing.h

@@ -0,0 +1,21 @@
+/*
+ *  Copyright (c) Facebook, Inc.
+ *
+ *  This source code is licensed under the MIT license found in the LICENSE
+ *  file in the root directory of this source tree.
+ *
+ */
+#ifndef __cplusplus
+#error This header can only be included in .mm (ObjC++) files
+#endif
+
+#import <Foundation/Foundation.h>
+
+#import <Flipper/FlipperClient.h>
+#import <FlipperKit/FlipperClient.h>
+
+@interface FlipperClient (Testing)
+
+- (instancetype)initWithCppClient:(facebook::flipper::FlipperClient *)cppClient;
+
+@end

iOS/FlipperKit/FlipperClient.mm

@@ -15,6 +15,7 @@
 #import <UIKit/UIKit.h>
 #include "SKStateUpdateCPPWrapper.h"
 #import "FlipperDiagnosticsViewController.h"
+#import "FlipperClient+Testing.h"
 
 #if !TARGET_OS_SIMULATOR
 //#import "SKPortForwardingServer.h"
@@ -177,4 +178,15 @@ using WrapperPlugin = facebook::flipper::FlipperCppWrapperPlugin;
 
 @end
 
+@implementation FlipperClient (Testing)
+
+- (instancetype)initWithCppClient:(facebook::flipper::FlipperClient *)cppClient {
+    if (self = [super init]) {
+        _cppClient = cppClient;
+    }
+    return self;
+}
+
+@end
+
 #endif