IVGCVSW-3030 Add a mock backend for unit testing

 * Added a mock implementation of an ArmNN backend for unit
   testing
 * Implemented a mock version of OptimizeSubgraphView
 * Fixed a typo in the Optimization API

Change-Id: Ic7acf7cc5c2a76a918e94cdc356baae7c7597a6d
Signed-off-by: Matteo Martincigh <matteo.martincigh@arm.com>
diff --git a/src/backends/backendsCommon/test/CMakeLists.txt b/src/backends/backendsCommon/test/CMakeLists.txt
index bc190dd..ab63679 100644
--- a/src/backends/backendsCommon/test/CMakeLists.txt
+++ b/src/backends/backendsCommon/test/CMakeLists.txt
@@ -30,6 +30,9 @@
     LstmTestImpl.hpp
     NormTestImpl.hpp
     MergerTestImpl.hpp
+    MockBackend.cpp
+    MockBackend.hpp
+    MockBackendId.hpp
     OptimizedNetworkTests.cpp
     PermuteTestImpl.hpp
     Pooling2dTestImpl.hpp