fixes Add null checks for JSON stream #154

Changes made:
* Change over to SWITCH statement in `streamTokens` method to improve readability
* Added token `VALUE_NULL` to deal with issue where object may have a field explicitly set to NULL as described in Issue Add null checks for JSON stream #154
* Added additional test to check for object with field explicitly set to NULL

Author: ImJohnMDaniel

sfdx-source/apex-mocks/main/classes/fflib_ApexMocksUtils.cls

@@ -189,39 +189,43 @@ public class fflib_ApexMocksUtils
 	private static void streamTokens(JSONParser fromStream, JSONGenerator toStream, JSONParserEvents events)
 	{
 		Integer depth = 0;
-		while (fromStream.nextToken()!=null)
+		while (fromStream.nextToken() != null)
 		{
 			// Give event handler chance to inject
-			if(events!=null)
+			if (events != null) {
 				events.nextToken(fromStream, depth, toStream);
-			// Forward to output stream
-			JSONToken currentToken = fromStream.getCurrentToken();
-			if(currentToken == JSONToken.START_ARRAY) {
-				toStream.writeStartArray();
-				depth++;
-			}
-			else if(currentToken == JSONToken.START_OBJECT) {
-				toStream.writeStartObject();
-				depth++;
 			}
-			else if(currentToken == JSONToken.FIELD_NAME)
-				toStream.writeFieldName(fromStream.getCurrentName());
-			else if(currentToken == JSONToken.VALUE_STRING ||
-					currentToken == JSONToken.VALUE_FALSE ||
-					currentToken == JSONToken.VALUE_TRUE ||
-					currentToken == JSONToken.VALUE_NUMBER_FLOAT ||
-					currentToken == JSONToken.VALUE_NUMBER_INT)
-				toStream.writeString(fromStream.getText());
-			else if(currentToken == JSONToken.END_OBJECT) {
-				toStream.writeEndObject();
-				depth--;
-			}
-			else if(currentToken == JSONToken.END_ARRAY) {
-				toStream.writeEndArray();
-				depth--;
+				
+			// Forward to output stream
+			switch on fromStream.getCurrentToken() {
+				when START_ARRAY {
+					toStream.writeStartArray();
+					depth++;
+				}
+				when START_OBJECT {
+					toStream.writeStartObject();
+					depth++;
+				}
+				when FIELD_NAME {
+					toStream.writeFieldName(fromStream.getCurrentName());
+				}
+				when VALUE_STRING, VALUE_FALSE, VALUE_TRUE, VALUE_NUMBER_FLOAT, VALUE_NUMBER_INT {
+					toStream.writeString(fromStream.getText());
+				}
+			    when VALUE_NULL {
+					toStream.writeNull();
+				}
+				when END_OBJECT {
+					toStream.writeEndObject();
+					depth--;
+				}
+				when END_ARRAY {
+					toStream.writeEndArray();
+					depth--;
+				}
 			}
 			// Don't continue to stream beyond the initial starting point
-			if(depth==0) 
+			if (depth == 0) 
 				break;
 		}
 	}

sfdx-source/apex-mocks/test/classes/fflib_ApexMocksUtilsTest.cls

@@ -85,7 +85,8 @@ public class fflib_ApexMocksUtilsTest
 	}
 
 	@isTest
-	private static void makeRelationship_GenericOverload_ReturnsObjectsWithRelationFieldSet() {
+	private static void makeRelationship_GenericOverload_ReturnsObjectsWithRelationFieldSet() 
+	{
 		//Given
 		SObject acc = Schema.getGlobalDescribe().get('Account').newSObject();
 		acc.put('Id', fflib_IDGenerator.generate(acc.getSObjectType()));
@@ -128,8 +129,8 @@ public class fflib_ApexMocksUtilsTest
 	}
 
 	@isTest
-	private static void makeRelationship_GenericOverload_ThrowsErrorOnInvalidParentType() {
-
+	private static void makeRelationship_GenericOverload_ThrowsErrorOnInvalidParentType() 
+	{
 		// Setup parent object
 		SObject acc = Schema.getGlobalDescribe().get('Account').newSObject();
 		acc.put('Id', fflib_IDGenerator.generate(acc.getSObjectType()));
@@ -155,8 +156,8 @@ public class fflib_ApexMocksUtilsTest
 	}
 
 	@isTest
-	private static void makeRelationship_GenericOverload_ThrowsErrorOnInvalidChildType() {
-
+	private static void makeRelationship_GenericOverload_ThrowsErrorOnInvalidChildType() 
+	{
 		// Setup parent object
 		SObject acc = Schema.getGlobalDescribe().get('Account').newSObject();
 		acc.put('Id', fflib_IDGenerator.generate(acc.getSObjectType()));
@@ -182,8 +183,8 @@ public class fflib_ApexMocksUtilsTest
 	}
 
 	@isTest
-	private static void makeRelationship_GenericOverload_ThrowsErrorOnInvalidFieldName() {
-
+	private static void makeRelationship_GenericOverload_ThrowsErrorOnInvalidFieldName() 
+	{
 		// Setup parent object
 		SObject acc = Schema.getGlobalDescribe().get('Account').newSObject();
 		acc.put('Id', fflib_IDGenerator.generate(acc.getSObjectType()));
@@ -208,6 +209,67 @@ public class fflib_ApexMocksUtilsTest
 		System.Assert.areEqual('SObject field not found: MyInvalidField', errorMessage);
 	}
 
+	@IsTest 
+	private static void makeRelationship_ObjectWithNull_DoesNotThrowErrorOnJSONExceptionCanNotWriteAFieldNameExpectingAValue() 
+	{	
+		// Given
+		Product2 prod1 = new Product2(
+			Id = fflib_IDGenerator.generate(Product2.SObjectType),
+			Name = 'Product1',
+			ProductCode = 'P1',
+			Description = null,
+			StockKeepingUnit = 'P1'
+		);
+
+		Product2 prod2 = new Product2(
+			Id = fflib_IDGenerator.generate(Product2.SObjectType),
+			Name = 'Product2',
+			ProductCode = 'P2',
+			Description = 'this is another product',
+			StockKeepingUnit = 'P2'
+		);
+
+		OrderItem oi1 = new OrderItem(
+			Id = fflib_IDGenerator.generate(OrderItem.SObjectType),
+			Product2Id = prod1.Id,
+			Product2 = prod1,
+			UnitPrice = 10,
+			Quantity = 1
+		);
+
+		OrderItem oi2 = new OrderItem(
+			Id = fflib_IDGenerator.generate(OrderItem.SObjectType),
+			Product2Id = prod2.Id,
+			Product2 = prod2,
+			UnitPrice = 10,
+			Quantity = 1
+		);
+
+		Order order = new Order();
+
+		Exception exceptionThatWasCalled = null;
+
+		// When
+		Test.startTest();
+		
+		try {
+			fflib_ApexMocksUtils.makeRelationship(
+				List<Order>.class,
+				new List<Order>{ order },
+				OrderItem.OrderId,
+				new List<List<OrderItem>>{ new List<OrderItem>{oi1, oi2} }
+			);
+		} catch (JSONException e) {
+			exceptionThatWasCalled = e;
+		}
+
+		Test.stopTest();
+
+		// Then
+		System.debug(exceptionThatWasCalled);
+		Assert.isNull(exceptionThatWasCalled, 'Exception should not have been called');
+	}
+
 	@isTest
 	static void setReadOnlyFields_CreatedByIdSetToCurrentUserId_IdFieldSetSuccessfully() {