Index: test/ELF/invalid/zunknown-flag.test
===================================================================
--- test/ELF/invalid/zunknown-flag.test
+++ test/ELF/invalid/zunknown-flag.test
@@ -0,0 +1,3 @@
+# RUN: not ld.lld -z obviouslyunknownflag 2>&1 | FileCheck --check-prefix=ERR %s
+# ERR: error: unknown -z value: obviouslyunknownflag
+