diff --git a/Tests/OutOfSource/OutOfSourceSubdir/CMakeLists.txt b/Tests/OutOfSource/OutOfSourceSubdir/CMakeLists.txt
index 15467c9cec..f3d378531c 100644
--- a/Tests/OutOfSource/OutOfSourceSubdir/CMakeLists.txt
+++ b/Tests/OutOfSource/OutOfSourceSubdir/CMakeLists.txt
@@ -1 +1,4 @@
-ADD_EXECUTABLE (simple simple.cxx)
+IF ("${PROJECT_SOURCE_DIR}" STREQUAL "${ANOTHER_PROJ_SOURCE_DIR}")
+  ADD_EXECUTABLE (simple simple.cxx)
+ENDIF ("${PROJECT_SOURCE_DIR}" STREQUAL "${ANOTHER_PROJ_SOURCE_DIR}")
+