Add SMTChecker tests for standard JSON

libdevcore/JSON.cpp

@@ -21,6 +21,8 @@
 
 #include "JSON.h"
 
+#include "CommonIO.h"
+
 #include <sstream>
 #include <map>
 #include <memory>
@@ -111,4 +113,10 @@ bool jsonParse(string const& _input, Json::Value& _json, string *_errs /* = null
 	return parse(readerBuilder, _input, _json, _errs);
 }
 
+bool jsonParseFile(string const& _fileName, Json::Value& _json, string *_errs /* = nullptr */)
+{
+	return jsonParse(readFileAsString(_fileName), _json, _errs);
+}
+
+
 } // namespace dev