From d3d1b4d224193b3e2a770b9a0255a0a97292d850 Mon Sep 17 00:00:00 2001
From: William Woodruff <woodruffw@users.noreply.github.com>
Date: Fri, 6 May 2016 09:29:20 -0400
Subject: [PATCH] duff: Add test.

Compares two equal files and asserts expected output.
---
 Formula/duff.rb | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Formula/duff.rb b/Formula/duff.rb
index 90f3c9f553..c7170be390 100644
--- a/Formula/duff.rb
+++ b/Formula/duff.rb
@@ -17,4 +17,17 @@ class Duff < Formula
                           "--mandir=#{man}"
     system "make", "install"
   end
+
+  test do
+    expected = <<-EOS.undent
+      2 files in cluster 1 (6 bytes, digest 8843d7f92416211de9ebb963ff4ce28125932878)
+      cmp1
+      cmp2
+    EOS
+
+    (testpath/"cmp1").write "foobar"
+    (testpath/"cmp2").write "foobar"
+
+    assert_equal expected, shell_output("#{bin}/duff cmp1 cmp2")
+  end
 end