diff --git a/TestHelper.cpp b/TestHelper.cpp
index 8c7345df9..5a579702a 100644
--- a/TestHelper.cpp
+++ b/TestHelper.cpp
@@ -228,25 +228,19 @@ byte toByte(json_spirit::mValue const& _v)
 	return 0;
 }
 
-bytes importByteArray(const std::string& str)
+bytes importByteArray(std::string const& _str)
 {
-    bytes data;
-    if (str.find_first_of("0x") == 0)
-            data = fromHex(str.substr(2));
-        else
-            data = fromHex(str);
-    return data;
+	return fromHex(_str.substr(0, 2) == "0x" ? _str.substr(2) : _str);
 }
 
 bytes importData(json_spirit::mObject& _o)
 {
 	bytes data;
 	if (_o["data"].type() == json_spirit::str_type)
-        data = importByteArray(_o["data"].get_str());
+		data = importByteArray(_o["data"].get_str());
 	else
 		for (auto const& j: _o["data"].get_array())
 			data.push_back(toByte(j));
-
 	return data;
 }
 
diff --git a/TestHelper.h b/TestHelper.h
index dc84b5567..ae6ea20cc 100644
--- a/TestHelper.h
+++ b/TestHelper.h
@@ -68,7 +68,7 @@ u256 toInt(json_spirit::mValue const& _v);
 byte toByte(json_spirit::mValue const& _v);
 bytes importCode(json_spirit::mObject& _o);
 bytes importData(json_spirit::mObject& _o);
-bytes importByteArray(const std::string& str);
+bytes importByteArray(std::string const& _str);
 eth::LogEntries importLog(json_spirit::mArray& _o);
 json_spirit::mArray exportLog(eth::LogEntries _logs);
 void checkOutput(bytes const& _output, json_spirit::mObject& _o);