diff --git a/CMakeLists.txt b/CMakeLists.txt
index 764bf928e..36876eea6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -22,6 +22,7 @@ target_link_libraries(testeth ethcore)
 target_link_libraries(testeth secp256k1)
 target_link_libraries(testeth solidity)
 target_link_libraries(testeth webthree)
+target_link_libraries(testeth natspec)
 
 if (JSONRPC)
 	target_link_libraries(testeth web3jsonrpc)
diff --git a/natspec.cpp b/natspec.cpp
new file mode 100644
index 000000000..827f96625
--- /dev/null
+++ b/natspec.cpp
@@ -0,0 +1,112 @@
+/*
+	This file is part of cpp-ethereum.
+
+	cpp-ethereum is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	cpp-ethereum is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
+ */
+/** @file natspec.cpp
+ * @author Marek Kotewicz <marek@ethdev.com>
+ * @date 2015
+ */
+
+#include <boost/test/unit_test.hpp>
+#include <libdevcore/Log.h>
+#include <libnatspec/NatspecExpressionEvaluator.h>
+
+using namespace std;
+
+BOOST_AUTO_TEST_SUITE(natspec)
+
+BOOST_AUTO_TEST_CASE(natspec_eval_function_exists)
+{
+	// given
+	NatspecExpressionEvaluator e;
+	// when
+	string result = e.evalExpression("`typeof evaluateExpression`").toStdString();
+	// then
+	BOOST_CHECK_EQUAL(result, "function");
+}
+
+BOOST_AUTO_TEST_CASE(natspec_js_eval)
+{
+	// given
+	NatspecExpressionEvaluator e;
+	// when
+	string result = e.evalExpression("`1 + 2`").toStdString();
+	// then
+	BOOST_CHECK_EQUAL(result, "3");
+}
+
+BOOST_AUTO_TEST_CASE(natspec_create_custom_function)
+{
+	// given
+	NatspecExpressionEvaluator e;
+	// when
+	auto x = e.evalExpression("`test = function (x) { return x + 'ok'; }`"); // ommit var, make it global
+	string result = e.evalExpression("`test(5)`").toStdString();
+	string result2 = e.evalExpression("`typeof test`").toStdString();
+	// then
+	BOOST_CHECK_EQUAL(result, "5ok");
+	BOOST_CHECK_EQUAL(result2, "function");
+}
+
+BOOST_AUTO_TEST_CASE(natspec_js_eval_separated_expressions)
+{
+	// given
+	NatspecExpressionEvaluator e;
+	// when
+	string result = e.evalExpression("`x = 1` + `y = 2` will be equal `x + y`").toStdString();
+	// then
+	BOOST_CHECK_EQUAL(result, "1 + 2 will be equal 3");
+}
+
+BOOST_AUTO_TEST_CASE(natspec_js_eval_input_params)
+{
+	// given
+	char const* abi = R"([
+	{
+		"name": "f",
+		"constant": false,
+		"type": "function",
+		"inputs": [
+		{
+			"name": "a",
+			"type": "uint256"
+		}
+		],
+		"outputs": [
+		{
+			"name": "d",
+			"type": "uint256"
+		}
+		]
+	}
+	])";
+	NatspecExpressionEvaluator e(abi, "'f'", "[4]");
+	// when
+	string result = e.evalExpression("Will multiply `a` by 7 and return `a * 7`.").toStdString();
+	// then
+	BOOST_CHECK_EQUAL(result, "Will multiply 4 by 7 and return 28.");
+}
+
+BOOST_AUTO_TEST_CASE(natspec_js_eval_error)
+{
+	// given
+	NatspecExpressionEvaluator e;
+	// when
+	string result = e.evalExpression("`test(`").toStdString();
+	// then
+	BOOST_CHECK_EQUAL(result, "`test(`");
+}
+
+BOOST_AUTO_TEST_SUITE_END()