add Chapter 15 - runtime observer implementation

Chapter15/observer/libs/etl/test/UnitTest++/CurrentTest.cpp

@@ -0,0 +1,18 @@
+#include "CurrentTest.h"
+#include <cstddef>
+
+namespace UnitTest {
+
+   UNITTEST_LINKAGE TestResults*& CurrentTest::Results()
+   {
+      static TestResults* testResults = NULL;
+      return testResults;
+   }
+
+   UNITTEST_LINKAGE const TestDetails*& CurrentTest::Details()
+   {
+      static const TestDetails* testDetails = NULL;
+      return testDetails;
+   }
+
+}