Added Update method to report on dbus

- Update method, updates timestamp and readings

Tested:
  - Added new unit tests covering update method
  - All existing unit tests are passing

Change-Id: I6b3829126d9060dbaf436cbf8e6917294dc03134
Signed-off-by: Krzysztof Grobelny <krzysztof.grobelny@intel.com>
diff --git a/tests/src/utils/set_exception.hpp b/tests/src/utils/set_exception.hpp
new file mode 100644
index 0000000..6680af0
--- /dev/null
+++ b/tests/src/utils/set_exception.hpp
@@ -0,0 +1,14 @@
+#pragma once
+
+#include <future>
+
+namespace utils
+{
+
+template <class T>
+inline void setException(std::promise<T>& promise, const std::string& message)
+{
+    promise.set_exception(std::make_exception_ptr(std::runtime_error(message)));
+}
+
+} // namespace utils