gengetopt: add test

Closes Homebrew/homebrew#38157.

Signed-off-by: Brett Koonce <koonce@gmail.com>

Formula/gengetopt.rb

@@ -1,10 +1,8 @@
-require 'formula'
-
 class Gengetopt < Formula
-  homepage 'http://www.gnu.org/software/gengetopt/'
-  url 'http://ftpmirror.gnu.org/gengetopt/gengetopt-2.22.6.tar.gz'
-  mirror 'http://ftp.gnu.org/gnu/gengetopt/gengetopt-2.22.6.tar.gz'
-  sha1 'c93bdec17f247aa32b3cd6530a6f68aa430d67f5'
+  homepage "https://www.gnu.org/software/gengetopt/"
+  url "http://ftpmirror.gnu.org/gengetopt/gengetopt-2.22.6.tar.gz"
+  mirror "https://ftp.gnu.org/gnu/gengetopt/gengetopt-2.22.6.tar.gz"
+  sha256 "30b05a88604d71ef2a42a2ef26cd26df242b41f5b011ad03083143a31d9b01f7"
 
   def install
     system "./configure", "--disable-dependency-tracking",
@@ -12,6 +10,21 @@ class Gengetopt < Formula
                           "--mandir=#{man}"
 
     ENV.deparallelize
-    system "make install"
+    system "make", "install"
+  end
+
+  test do
+    ggo = <<-EOS.undent
+      package "homebrew"
+      version "0.9.5"
+      purpose "The missing package manager for OS X"
+
+      option "verbose" v "be verbose"
+    EOS
+
+    pipe_output("#{bin}/gengetopt --file-name=test", ggo, 0)
+    assert File.exist? "test.h"
+    assert File.exist? "test.c"
+    assert_match(/verbose_given/, File.read("test.h"))
   end
 end