diff --git a/test/average_unittest.cpp b/test/average_unittest.cpp
new file mode 100644
index 0000000..9eef0f8
--- /dev/null
+++ b/test/average_unittest.cpp
@@ -0,0 +1,49 @@
+#include "average.hpp"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+using ::testing::Return;
+
+TEST(SensorKeyTest, InvalidSensorKey)
+{
+    Average av;
+
+    av.setAverageValue(std::make_pair("power", "0"), std::make_pair(0L, 0L));
+    av.setAverageValue(std::make_pair("power", "1"), std::make_pair(0L, 0L));
+
+    EXPECT_FALSE(av.getAverageValue(std::make_pair("power", "4")));
+}
+
+TEST(SensorKeyTest, ValidSensorKey)
+{
+    Average av;
+
+    av.setAverageValue(std::make_pair("power", "0"), std::make_pair(0L, 0L));
+    av.setAverageValue(std::make_pair("power", "1"), std::make_pair(2L, 2L));
+
+    auto value = av.getAverageValue(std::make_pair("power", "1"));
+    EXPECT_TRUE(value == std::make_pair(2L, 2L));
+}
+
+TEST(AverageTest, ZeroDelta)
+{
+    Average av;
+
+    EXPECT_FALSE(av.calcAverage(1L, 1L, 2L, 1L));
+}
+
+TEST(AverageTest, NegativeDelta)
+{
+    Average av;
+
+    ASSERT_DEATH(av.calcAverage(1L, 1L, 2L, 0L), "");
+}
+
+TEST(AverageTest, RightAverage)
+{
+    Average av;
+
+    EXPECT_TRUE(38837438L == av.calcAverage(27624108L, 132864155500L, 27626120L,
+                                            132887999500L));
+}