Disabled the wrong ShellCheck check.
diff --git a/shflags_test_helpers b/shflags_test_helpers
index 5e48868..06d97f6 100644
--- a/shflags_test_helpers
+++ b/shflags_test_helpers
@@ -14,7 +14,7 @@
 # $() are not fully portable (POSIX != portable).
 #   shellcheck disable=SC2006
 # Arrays are not available in all shells.
-#   shellcheck disable=SC2090
+#   shellcheck disable=SC2089
 # Disagree with [ p ] && [ q ] vs [ p -a -q ] recommendation.
 #   shellcheck disable=SC2166