diff --git a/tests/nsl/CMakeLists.txt b/tests/nsl/CMakeLists.txt
index c8c5f31e5..cbd4b12d1 100644
--- a/tests/nsl/CMakeLists.txt
+++ b/tests/nsl/CMakeLists.txt
@@ -1,4 +1,5 @@
 add_subdirectory(dft)
 add_subdirectory(diff)
 add_subdirectory(int)
 add_subdirectory(sf)
+add_subdirectory(smooth)
diff --git a/tests/nsl/smooth/CMakeLists.txt b/tests/nsl/smooth/CMakeLists.txt
new file mode 100644
index 000000000..659f521f1
--- /dev/null
+++ b/tests/nsl/smooth/CMakeLists.txt
@@ -0,0 +1,9 @@
+INCLUDE_DIRECTORIES(${GSL_INCLUDE_DIR})
+add_executable (nslsmoothtest NSLSmoothTest.cpp)
+
+target_link_libraries(nslsmoothtest Qt5::Test)
+target_link_libraries(nslsmoothtest ${GSL_LIBRARIES} ${GSL_CBLAS_LIBRARIES})
+
+target_link_libraries(nslsmoothtest labplot2lib)
+
+add_test(NAME nslsmoothtest COMMAND nslsmoothtest)
diff --git a/tests/nsl/smooth/NSLSmoothTest.cpp b/tests/nsl/smooth/NSLSmoothTest.cpp
new file mode 100644
index 000000000..a9221535d
--- /dev/null
+++ b/tests/nsl/smooth/NSLSmoothTest.cpp
@@ -0,0 +1,104 @@
+/***************************************************************************
+    File                 : NSLSmoothTest.cpp
+    Project              : LabPlot
+    Description          : NSL Tests for smoothing
+    --------------------------------------------------------------------
+    Copyright            : (C) 2019 Stefan Gerlach (stefan.gerlach@uni.kn)
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *  This program 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 2 of the License, or      *
+ *  (at your option) any later version.                                    *
+ *                                                                         *
+ *  This program 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 this program; if not, write to the Free Software           *
+ *   Foundation, Inc., 51 Franklin Street, Fifth Floor,                    *
+ *   Boston, MA  02110-1301  USA                                           *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "NSLSmoothTest.h"
+#include "backend/lib/macros.h"
+
+extern "C" {
+#include "backend/nsl/nsl_smooth.h"
+}
+
+void NSLSmoothTest::initTestCase() {
+	const QString currentDir = __FILE__;
+	m_dataDir = currentDir.left(currentDir.lastIndexOf(QDir::separator())) + QDir::separator() + QLatin1String("data") + QDir::separator();
+}
+
+//##############################################################################
+//#################  moving average tests
+//##############################################################################
+
+const int N = 9;
+const int points = 5;
+const nsl_smooth_weight_type weight = nsl_smooth_weight_uniform;
+
+void NSLSmoothTest::testMA_padnone() {
+	double data[] = {2, 2, 5, 2, 1, 0, 1, 4, 9};
+	double result[] = {2, 3, 2.4, 2, 1.8, 1.6, 3, 14/3., 9};
+        
+	int status = nsl_smooth_moving_average(data, N, points, weight, nsl_smooth_pad_none);
+	QCOMPARE(status, 0);
+	for(int i = 0; i < N; i++)
+		QCOMPARE(data[i], result[i]);
+}
+
+void NSLSmoothTest::testMA_padmirror() {
+	double data[] = {2, 2, 5, 2, 1, 0, 1, 4, 9};
+	double result[] = {3.2, 2.6, 2.4, 2, 1.8, 1.6, 3, 3.6, 3.8};
+        
+	int status = nsl_smooth_moving_average(data, N, points, weight, nsl_smooth_pad_mirror);
+	QCOMPARE(status, 0);
+	for(int i = 0; i < N; i++)
+		QCOMPARE(data[i], result[i]);
+}
+
+void NSLSmoothTest::testMA_padnearest() {
+	double data[] = {2, 2, 5, 2, 1, 0, 1, 4, 9};
+	double result[] = {2.6, 2.6, 2.4, 2, 1.8, 1.6, 3, 4.6, 6.4};
+        
+	int status = nsl_smooth_moving_average(data, N, points, weight, nsl_smooth_pad_nearest);
+	QCOMPARE(status, 0);
+	for(int i = 0; i < N; i++)
+		QCOMPARE(data[i], result[i]);
+}
+
+void NSLSmoothTest::testMA_padconstant() {
+	double data[] = {2, 2, 5, 2, 1, 0, 1, 4, 9};
+	double result[] = {1.8, 2.2, 2.4, 2, 1.8, 1.6, 3, 2.8, 2.8};
+        
+	int status = nsl_smooth_moving_average(data, N, points, weight, nsl_smooth_pad_constant);
+	QCOMPARE(status, 0);
+	for(int i = 0; i < N; i++)
+		QCOMPARE(data[i], result[i]);
+}
+
+void NSLSmoothTest::testMA_padperiodic() {
+	double data[] = {2, 2, 5, 2, 1, 0, 1, 4, 9};
+	double result[] = {4.4, 4, 2.4, 2, 1.8, 1.6, 3, 3.2, 3.6};
+        
+	int status = nsl_smooth_moving_average(data, N, points, weight, nsl_smooth_pad_periodic);
+	QCOMPARE(status, 0);
+	for(int i = 0; i < N; i++)
+		QCOMPARE(data[i], result[i]);
+}
+
+//##############################################################################
+//#################  performance
+//##############################################################################
+
+//TODO
+
+QTEST_MAIN(NSLSmoothTest)
diff --git a/tests/nsl/smooth/NSLSmoothTest.h b/tests/nsl/smooth/NSLSmoothTest.h
new file mode 100644
index 000000000..9f96b542c
--- /dev/null
+++ b/tests/nsl/smooth/NSLSmoothTest.h
@@ -0,0 +1,51 @@
+/***************************************************************************
+    File                 : NSLDiffTest.h
+    Project              : LabPlot
+    Description          : NSL Tests for smoothing
+    --------------------------------------------------------------------
+    Copyright            : (C) 2019 Stefan Gerlach (stefan.gerlach@uni.kn)
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *  This program 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 2 of the License, or      *
+ *  (at your option) any later version.                                    *
+ *                                                                         *
+ *  This program 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 this program; if not, write to the Free Software           *
+ *   Foundation, Inc., 51 Franklin Street, Fifth Floor,                    *
+ *   Boston, MA  02110-1301  USA                                           *
+ *                                                                         *
+ ***************************************************************************/
+#ifndef NSLSMOOTHTEST_H
+#define NSLSMOOTHTEST_H
+
+#include <QtTest>
+
+class NSLSmoothTest : public QObject {
+	Q_OBJECT
+
+private slots:
+	void initTestCase();
+
+	// moving average tests
+	void testMA_padnone();
+	void testMA_padmirror();
+	void testMA_padnearest();
+	void testMA_padconstant();
+	void testMA_padperiodic();
+	// TODO: other types
+
+	// TODO: performance
+	//void testPerformance();
+private:
+	QString m_dataDir;
+};
+#endif