Fix: sharedPurchases nullability

Purchases/Public/RCPurchases.h

@@ -152,11 +152,18 @@ NS_SWIFT_NAME(Purchases)
 
 /**
  @return A singleton `RCPurchases` object. Call this after a configure method to access the singleton.
+ @note: If the SDK has not been configured, calls to sharedPurchases will raise an exception. Make sure to configure the SDK before making calls to sharedPurchases.
  */
 @property (class, nonatomic, readonly) RCPurchases *sharedPurchases;
 
 #pragma mark Configuration
 
+/**
+ @note True if the SDK has been configured, false otherwise. This property should only be used in special circumstances. If the shared instance has not been configured,
+ calls made to it will raise an exception.
+ */
+@property (class, nonatomic, readonly) BOOL isConfigured;
+
 /** Set this to true if you are passing in an appUserID but it is anonymous, this is true by default if you didn't pass an appUserID
  If a user tries to purchase a product that is active on the current app store account, we will treat it as a restore and alias
  the new ID with the previous id.

Purchases/Public/RCPurchases.m

@@ -138,10 +138,12 @@ - (void)setFinishTransactions:(BOOL)finishTransactions {
     self.systemInfo.finishTransactions = finishTransactions;
 }
 
++ (BOOL)isConfigured {
+    return _sharedPurchases != nil;
+}
+
 + (instancetype)sharedPurchases {
-    if (!_sharedPurchases) {
-        RCWarnLog(@"%@", RCStrings.configure.no_singleton_instance);
-    }
+    NSCAssert(_sharedPurchases, RCStrings.configure.no_singleton_instance);
     return _sharedPurchases;
 }
 

PurchasesTests/Purchasing/PurchasesTests.swift

@@ -250,7 +250,19 @@ class PurchasesTests: XCTestCase {
         setupPurchases()
         expect(self.purchases).toNot(beNil())
     }
+
+    func testUsingSharedInstanceWithoutInitializingRaisesException() {
+        expect{ Purchases.shared }.to(raiseException())
+        setupPurchases()
+        expect{ Purchases.shared }.toNot(raiseException())
+    }
 
+    func testIsConfiguredReturnsCorrectvalue() {
+        expect(Purchases.isConfigured) == false
+        setupPurchases()
+        expect(Purchases.isConfigured) == true
+    }
+
     func testFirstInitializationCallDelegate() {
         setupPurchases()
         expect(self.purchasesDelegate.purchaserInfoReceivedCount).toEventually(equal(1))