diff --git a/test/fuzzTesting/fuzzHelper.cpp b/test/fuzzTesting/fuzzHelper.cpp
index de7f56dc9..02404a9f2 100644
--- a/test/fuzzTesting/fuzzHelper.cpp
+++ b/test/fuzzTesting/fuzzHelper.cpp
@@ -74,7 +74,7 @@ std::string RandomCode::generate(int _maxOpNumber, RandomCodeOptions _options)
 		uint8_t opcode = weightsDefined ? randOpCodeWeight() : randOpCodeGen();
 		dev::eth::InstructionInfo info = dev::eth::instructionInfo((dev::eth::Instruction) opcode);
 
-		if (info.name.find_first_of("INVALID_INSTRUCTION") > 0)
+		if (info.name.find("INVALID_INSTRUCTION") != std::string::npos)
 		{
 			//Byte code is yet not implemented
 			if (_options.useUndefinedOpCodes == false)
@@ -85,12 +85,12 @@ std::string RandomCode::generate(int _maxOpNumber, RandomCodeOptions _options)
 		}
 		else
 		{
-			if (info.name.find_first_of("PUSH") > 0)
+			if (info.name.find("PUSH") != std::string::npos)
 				code += toCompactHex(opcode);
 			code += fillArguments((dev::eth::Instruction) opcode, _options);
 		}
 
-		if (info.name.find_first_of("PUSH") <= 0)
+		if (info.name.find("PUSH") == std::string::npos)
 		{
 			std::string byte = toCompactHex(opcode);
 			code += (byte == "") ? "00" : byte;
@@ -145,117 +145,67 @@ std::string RandomCode::fillArguments(dev::eth::Instruction _opcode, RandomCodeO
 	unsigned num = info.args;
 	int rand = randUniIntGen() % 100;
 	if (rand < _options.smartCodeProbability)
-		smart = true;
+		smart = true;	
 
 	if (smart)
 	{
-		switch (_opcode)
+		//PUSH1 ... PUSH32
+		if (int(dev::eth::Instruction::PUSH1) <= int(_opcode) && int(_opcode) <= int(dev::eth::Instruction::PUSH32))
+		{
+		  code += rndByteSequence(int(_opcode) - int(dev::eth::Instruction::PUSH1) + 1);
+		  return code;
+		}
+
+		//SWAP1 ... SWAP16 || DUP1 ... DUP16
+		if ((int(dev::eth::Instruction::SWAP1) <= int(_opcode) && int(_opcode) <= int(dev::eth::Instruction::SWAP16))
+			|| (int(dev::eth::Instruction::DUP1) <= int(_opcode) && int(_opcode) <= int(dev::eth::Instruction::DUP16)))
 		{
-		case dev::eth::Instruction::PUSH1:	code += rndByteSequence(1);	break;
-		case dev::eth::Instruction::PUSH2:	code += rndByteSequence(2);	break;
-		case dev::eth::Instruction::PUSH3:	code += rndByteSequence(3);	break;
-		case dev::eth::Instruction::PUSH4:	code += rndByteSequence(4);	break;
-		case dev::eth::Instruction::PUSH5:	code += rndByteSequence(5);	break;
-		case dev::eth::Instruction::PUSH6:	code += rndByteSequence(6);	break;
-		case dev::eth::Instruction::PUSH7:	code += rndByteSequence(7);	break;
-		case dev::eth::Instruction::PUSH8:	code += rndByteSequence(8);	break;
-		case dev::eth::Instruction::PUSH9:	code += rndByteSequence(9);	break;
-		case dev::eth::Instruction::PUSH10:	code += rndByteSequence(10); break;
-		case dev::eth::Instruction::PUSH11:	code += rndByteSequence(11); break;
-		case dev::eth::Instruction::PUSH12:	code += rndByteSequence(12); break;
-		case dev::eth::Instruction::PUSH13:	code += rndByteSequence(13); break;
-		case dev::eth::Instruction::PUSH14:	code += rndByteSequence(14); break;
-		case dev::eth::Instruction::PUSH15:	code += rndByteSequence(15); break;
-		case dev::eth::Instruction::PUSH16:	code += rndByteSequence(16); break;
-		case dev::eth::Instruction::PUSH17:	code += rndByteSequence(17); break;
-		case dev::eth::Instruction::PUSH18:	code += rndByteSequence(18); break;
-		case dev::eth::Instruction::PUSH19:	code += rndByteSequence(19); break;
-		case dev::eth::Instruction::PUSH20:	code += rndByteSequence(20); break;
-		case dev::eth::Instruction::PUSH21:	code += rndByteSequence(21); break;
-		case dev::eth::Instruction::PUSH22:	code += rndByteSequence(22); break;
-		case dev::eth::Instruction::PUSH23:	code += rndByteSequence(23); break;
-		case dev::eth::Instruction::PUSH24:	code += rndByteSequence(24); break;
-		case dev::eth::Instruction::PUSH25:	code += rndByteSequence(25); break;
-		case dev::eth::Instruction::PUSH26:	code += rndByteSequence(26); break;
-		case dev::eth::Instruction::PUSH27:	code += rndByteSequence(27); break;
-		case dev::eth::Instruction::PUSH28:	code += rndByteSequence(28); break;
-		case dev::eth::Instruction::PUSH29:	code += rndByteSequence(29); break;
-		case dev::eth::Instruction::PUSH30:	code += rndByteSequence(30); break;
-		case dev::eth::Instruction::PUSH31:	code += rndByteSequence(31); break;
-		case dev::eth::Instruction::PUSH32:	code += rndByteSequence(32); break;
-		case dev::eth::Instruction::SWAP1:
-		case dev::eth::Instruction::SWAP2:
-		case dev::eth::Instruction::SWAP3:
-		case dev::eth::Instruction::SWAP4:
-		case dev::eth::Instruction::SWAP5:
-		case dev::eth::Instruction::SWAP6:
-		case dev::eth::Instruction::SWAP7:
-		case dev::eth::Instruction::SWAP8:
-		case dev::eth::Instruction::SWAP9:
-		case dev::eth::Instruction::SWAP10:
-		case dev::eth::Instruction::SWAP11:
-		case dev::eth::Instruction::SWAP12:
-		case dev::eth::Instruction::SWAP13:
-		case dev::eth::Instruction::SWAP14:
-		case dev::eth::Instruction::SWAP15:
-		case dev::eth::Instruction::SWAP16:
-		case dev::eth::Instruction::DUP1:
-		case dev::eth::Instruction::DUP2:
-		case dev::eth::Instruction::DUP3:
-		case dev::eth::Instruction::DUP4:
-		case dev::eth::Instruction::DUP5:
-		case dev::eth::Instruction::DUP6:
-		case dev::eth::Instruction::DUP7:
-		case dev::eth::Instruction::DUP8:
-		case dev::eth::Instruction::DUP9:
-		case dev::eth::Instruction::DUP10:
-		case dev::eth::Instruction::DUP11:
-		case dev::eth::Instruction::DUP12:
-		case dev::eth::Instruction::DUP13:
-		case dev::eth::Instruction::DUP14:
-		case dev::eth::Instruction::DUP15:
-		case dev::eth::Instruction::DUP16:
 			int times;
 			switch (_opcode)
 			{
-				case dev::eth::Instruction::DUP1:	times = 1; break;
-				case dev::eth::Instruction::SWAP1:
-				case dev::eth::Instruction::DUP2:	times = 2; break;
-				case dev::eth::Instruction::SWAP2:
-				case dev::eth::Instruction::DUP3:	times = 3; break;
-				case dev::eth::Instruction::SWAP3:
-				case dev::eth::Instruction::DUP4:	times = 4; break;
-				case dev::eth::Instruction::SWAP4:
-				case dev::eth::Instruction::DUP5:	times = 5; break;
-				case dev::eth::Instruction::SWAP5:
-				case dev::eth::Instruction::DUP6:	times = 6; break;
-				case dev::eth::Instruction::SWAP6:
-				case dev::eth::Instruction::DUP7:	times = 7; break;
-				case dev::eth::Instruction::SWAP7:
-				case dev::eth::Instruction::DUP8:	times = 8; break;
-				case dev::eth::Instruction::SWAP8:
-				case dev::eth::Instruction::DUP9:	times = 9; break;
-				case dev::eth::Instruction::SWAP9:
-				case dev::eth::Instruction::DUP10:	times = 10; break;
-				case dev::eth::Instruction::SWAP10:
-				case dev::eth::Instruction::DUP11:	times = 11; break;
-				case dev::eth::Instruction::SWAP11:
-				case dev::eth::Instruction::DUP12:	times = 12; break;
-				case dev::eth::Instruction::SWAP12:
-				case dev::eth::Instruction::DUP13:	times = 13; break;
-				case dev::eth::Instruction::SWAP13:
-				case dev::eth::Instruction::DUP14:	times = 14; break;
-				case dev::eth::Instruction::SWAP14:
-				case dev::eth::Instruction::DUP15:	times = 15; break;
-				case dev::eth::Instruction::SWAP15:
-				case dev::eth::Instruction::DUP16:	times = 16; break;
-				case dev::eth::Instruction::SWAP16:	times = 17; break;
-				default: times = 1;
+			case dev::eth::Instruction::DUP1:	times = 1; break;
+			case dev::eth::Instruction::SWAP1:
+			case dev::eth::Instruction::DUP2:	times = 2; break;
+			case dev::eth::Instruction::SWAP2:
+			case dev::eth::Instruction::DUP3:	times = 3; break;
+			case dev::eth::Instruction::SWAP3:
+			case dev::eth::Instruction::DUP4:	times = 4; break;
+			case dev::eth::Instruction::SWAP4:
+			case dev::eth::Instruction::DUP5:	times = 5; break;
+			case dev::eth::Instruction::SWAP5:
+			case dev::eth::Instruction::DUP6:	times = 6; break;
+			case dev::eth::Instruction::SWAP6:
+			case dev::eth::Instruction::DUP7:	times = 7; break;
+			case dev::eth::Instruction::SWAP7:
+			case dev::eth::Instruction::DUP8:	times = 8; break;
+			case dev::eth::Instruction::SWAP8:
+			case dev::eth::Instruction::DUP9:	times = 9; break;
+			case dev::eth::Instruction::SWAP9:
+			case dev::eth::Instruction::DUP10:	times = 10; break;
+			case dev::eth::Instruction::SWAP10:
+			case dev::eth::Instruction::DUP11:	times = 11; break;
+			case dev::eth::Instruction::SWAP11:
+			case dev::eth::Instruction::DUP12:	times = 12; break;
+			case dev::eth::Instruction::SWAP12:
+			case dev::eth::Instruction::DUP13:	times = 13; break;
+			case dev::eth::Instruction::SWAP13:
+			case dev::eth::Instruction::DUP14:	times = 14; break;
+			case dev::eth::Instruction::SWAP14:
+			case dev::eth::Instruction::DUP15:	times = 15; break;
+			case dev::eth::Instruction::SWAP15:
+			case dev::eth::Instruction::DUP16:	times = 16; break;
+			case dev::eth::Instruction::SWAP16:	times = 17; break;
+			default: times = 1;
 			}
+
 			for (int i = 0; i < times; i ++)
 				code += getPushCode(randUniIntGen() % 32);
 
-		break;
+			return code;
+		}
+
+		switch (_opcode)
+		{
 		case dev::eth::Instruction::CREATE:
 			//(CREATE value mem1 mem2)
 			code += getPushCode(randUniIntGen() % 128);  //memlen1