Created metric class

Metric collects updates from sensor. Report displays metric readings
depending on reportingType.

Tested:
  - Added new units tests for Metric class
  - All other unit tests are passing

Change-Id: I19f4831fab163a4f9540cef7bb23e903ae90fddf
Signed-off-by: Krzysztof Grobelny <krzysztof.grobelny@intel.com>
diff --git a/tests/src/test_sensor_cache.cpp b/tests/src/test_sensor_cache.cpp
index cf31add..0db3bc2 100644
--- a/tests/src/test_sensor_cache.cpp
+++ b/tests/src/test_sensor_cache.cpp
@@ -1,7 +1,7 @@
+#include "helpers/sensor_id_helpers.hpp"
 #include "mocks/sensor_mock.hpp"
 #include "printers.hpp"
 #include "sensor_cache.hpp"
-#include "utils/sensor_id_eq.hpp"
 
 #include <initializer_list>
 
@@ -100,5 +100,5 @@
 
     auto expected = SensorMock::makeId("sensor-service", "sensor-path");
 
-    ASSERT_THAT(id, sensorIdEq(expected));
+    ASSERT_THAT(id, Eq(expected));
 }