diff --git a/external/CMakeLists.txt b/external/CMakeLists.txt
index 86b0e1618f80fc12768e03f704e1ddf4ea25f227..fe9f1da40310132c2bba0ffa1782bee5b4c75e50 100644
--- a/external/CMakeLists.txt
+++ b/external/CMakeLists.txt
@@ -73,4 +73,11 @@ else()
   set_target_properties(external::fles_logging PROPERTIES
                         IMPORTED_LOCATION external::fles_logging-NOTFOUND
              )
+
+  # Define an empty macro such that ctest is happy when no externals are
+  # available
+  # This is needed since to speed up the execution of the code format check 
+  # no externals are downloaded
+  macro(xpu_attach)
+  endmacro()
 endif()