1 files changed, 5 insertions, 0 deletions
diff --git a/Library/Formula/abnfgen.rb b/Library/Formula/abnfgen.rb
index 34126ff08..f1b76ec3d 100644
--- a/Library/Formula/abnfgen.rb
+++ b/Library/Formula/abnfgen.rb
@@ -11,4 +11,9 @@ class Abnfgen < Formula
                           "--mandir=#{man}"
     system "make install"
   end
+
+  test do
+    (testpath/"grammar").write %(ring = 1*12("ding" SP) "dong" CRLF)
+    system "#{bin}/abnfgen", (testpath/"grammar")
+  end
 end