Added a mock sharedInstance to fix watchOS crash

Tests/Unit-Tests/NewRelicAgentTests/Analytics-Tests/PersistentStoreTests.m

@@ -14,6 +14,8 @@
 #import "NRMACustomEvent.h"
 #import "NRMARequestEvent.h"
 #import "NRMAInteractionEvent.h"
+#import "NewRelicAgentInternal.h"
+#import <OCMock/OCMock.h>
 
 #import "BlockAttributeValidator.h"
 #import "NRMAFlags.h"
@@ -65,8 +67,12 @@ - (nullable instancetype)initWithCoder:(nonnull NSCoder *)coder {
 @end
 
 @interface PersistentStoreTests : XCTestCase
+@property id mockNewRelicInternals;
+
 @end
 
+static NewRelicAgentInternal* _sharedInstance;
+
 @implementation PersistentStoreTests {
     BlockAttributeValidator *agreeableAttributeValidator;
 }
@@ -77,7 +83,11 @@ @implementation PersistentStoreTests {
 
 - (void)setUp {
     [super setUp];
-
+    self.mockNewRelicInternals = [OCMockObject mockForClass:[NewRelicAgentInternal class]];
+    _sharedInstance = [[NewRelicAgentInternal alloc] init];
+    _sharedInstance.analyticsController = [[NRMAAnalytics alloc] initWithSessionStartTimeMS:0.0];
+    [[[[self.mockNewRelicInternals stub] classMethod] andReturn:_sharedInstance] sharedInstance];
+
     if(agreeableAttributeValidator == nil) {
         agreeableAttributeValidator = [[BlockAttributeValidator alloc] initWithNameValidator:^BOOL(NSString *) {
             return YES;