diff --git a/tests/docker/Makefile.include b/tests/docker/Makefile.include
index 0779dab5b9..bdc53ddfcf 100644
--- a/tests/docker/Makefile.include
+++ b/tests/docker/Makefile.include
@@ -209,7 +209,7 @@ endif
 	@echo '                         before running the command.'
 	@echo '    NETWORK=1            Enable virtual network interface with default backend.'
 	@echo '    NETWORK=$$BACKEND     Enable virtual network interface with $$BACKEND.'
-	@echo '    NOUSER               Define to disable adding current user to containers passwd.'
+	@echo '    NOUSER=1             Define to disable adding current user to containers passwd.'
 	@echo '    NOCACHE=1            Ignore cache when build images.'
 	@echo '    EXECUTABLE=<path>    Include executable in image.'
 	@echo '    EXTRA_FILES="<path> [... <path>]"'