Add tests

Rakefile

@@ -1,5 +1,6 @@
 require 'rubygems'
 require 'rake/gempackagetask'
+require 'rake/testtask'
 
 WINDOWS = (PLATFORM =~ /win32|cygwin/ ? true : false) rescue false
 SUDO = WINDOWS ? '' : 'sudo'
@@ -20,3 +21,6 @@ desc 'Build the extension'
 task :build do
   sh "cd ext && ruby extconf.rb && make clean && make"
 end
+
+Rake::TestTask.new
+

test/test_ripper.rb

@@ -0,0 +1,14 @@
+require "test/unit"
+require File.dirname(__FILE__) + '/../lib/ripper'
+
+class TestRipper < Test::Unit::TestCase
+  def test_ripper
+    sexp = Ripper.sexp("module Foo; def v=(value) value += 1 end end")
+    assert_equal sexp, [:program, 
+      [[:module, [:const_ref, [:@const, "Foo", [1, 7]]], [:bodystmt, [[:void_stmt], 
+      [:def, [:@ident, "v=", [1, 16]], [:paren, [:params, [[:@ident, "value", [1, 19]]], 
+      nil, nil, nil, nil]], [:bodystmt, [[:opassign, [:var_field, [:@ident, "value", 
+        [1, 26]]], [:@op, "+=", [1, 32]], [:@int, "1", [1, 35]]]], nil, nil, nil]]], 
+        nil, nil, nil]]]]
+  end
+end