Trying to write tests for xylib

example.sh

arc-mac-04:samples bcomnes$ echo "20.0 490.5" > test.txt
arc-mac-04:samples bcomnes$ cat test.txt 
20.0 490.5
arc-mac-04:samples bcomnes$ xyconv -g test.txt 
text: ascii text

results.rb

brew test xylib --verbose --debug
/Users/bcomnes/homebrew/Library/brew.rb (Formulary::StandardLoader): loading /Users/bcomnes/homebrew/Library/Taps/homebrew/homebrew-science/xylib.rb
Testing xylib
==> /Users/bcomnes/homebrew/Cellar/xylib/1.3/bin/xyconv --version
1.3.0
==> /Users/bcomnes/homebrew/Cellar/xylib/1.3/bin/xyconv -g /private/tmp/xylib-mjAY/with_sigma.txt
Usage:
	xyconv [-t FILETYPE] [-x OPTION] INPUT_FILE OUTPUT_FILE
	xyconv [-t FILETYPE] [-x OPTION] -m INPUT_FILE1 ...
	xyconv -i FILETYPE
	xyconv -g INPUT_FILE ...
	xyconv [-l|-v|-h]
  Converts INPUT_FILE to ascii OUTPUT_FILE
  -t     specify filetype of input file
  -x     specify option for filetype (can be used more than once)
  -m     convert one or multiple files; output files have the same name
         as input, but with extension changed to .xy
  -l     list all supported file types
  -v     output version information and exit
  -h     show this help message and exit
  -i     show information about filetype
  -s     do not output metadata
  -g     guess filetype of file 
  To write the results to standard output use `-' as OUTPUT_FILE
Error: xylib: failed
Failed executing: /Users/bcomnes/homebrew/Cellar/xylib/1.3/bin/xyconv -g\ /private/tmp/xylib-mjAY/with_sigma.txt
/Users/bcomnes/homebrew/Library/Homebrew/formula.rb:560:in `system'
/Users/bcomnes/homebrew/Library/Homebrew/formula.rb:544:in `open'
/Users/bcomnes/homebrew/Library/Homebrew/formula.rb:544:in `system'
/Users/bcomnes/homebrew/Library/Taps/homebrew/homebrew-science/xylib.rb:22
/Users/bcomnes/homebrew/Library/Homebrew/formula.rb:487:in `instance_eval'
/Users/bcomnes/homebrew/Library/Homebrew/formula.rb:487:in `test'
/Users/bcomnes/homebrew/Library/Homebrew/extend/fileutils.rb:21:in `mktemp'
/Users/bcomnes/homebrew/Library/Homebrew/formula.rb:485:in `test'
/Users/bcomnes/homebrew/Library/Homebrew/cmd/test.rb:54:in `test'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/timeout.rb:67:in `timeout'
/Users/bcomnes/homebrew/Library/Homebrew/cmd/test.rb:53:in `test'
/Users/bcomnes/homebrew/Library/Homebrew/cmd/test.rb:34:in `each'
/Users/bcomnes/homebrew/Library/Homebrew/cmd/test.rb:34:in `test'
/Users/bcomnes/homebrew/Library/brew.rb:131:in `send'
/Users/bcomnes/homebrew/Library/brew.rb:131

xylib.rb

require "formula"

class Xylib < Formula
  homepage "http://xylib.sourceforge.net"
  url "https://github.com/wojdyr/xylib/releases/download/v1.3/xylib-1.3.tar.bz2"
  sha1 "61d95a9d3c98239fd4fb335fadadd85be3001a89"

  depends_on "boost" => :build
  depends_on "zlib" => :recommended

  def install
    system "./configure", "--disable-debug",
                          "--disable-dependency-tracking",
                          "--disable-silent-rules",
                          "--prefix=#{prefix}"
    system "make", "install"
  end

  test do
    system bin/"xyconv", "--version"
    (testpath/'with_sigma.txt').write('20.0 490.5')
    system "#{bin}/xyconv", "-g\ #{testpath}/with_sigma.txt"
  end
end