diff --git a/tests/testcase.sh b/tests/testcase.sh
index 56aebe2..fae7443 100755
--- a/tests/testcase.sh
+++ b/tests/testcase.sh
@@ -15,7 +15,8 @@ stdout_observed="$wasm.stdout.observed"
 stderr_observed="$wasm.stderr.observed"
 exit_status_observed="$wasm.exit_status.observed"
 
-# If we don't have a runwasi command, we're just doing compile-only testing.
+# Double-check that a runwasi command was specified since otherwise this script
+# was invoked with no arguments which isn't as intended.
 if [ "$runwasi" == "" ]; then
     exit 1
 fi