test: runner restores current dir

PDoc::Generators::Html::Website#render is using Dir.chdir
to change to the :output dir and not restoring the current
working dir.

This new test fails.

Author: stepheneb

.gitignore

@@ -1,2 +1,3 @@
 .DS_Store
 *.gem
+output

test/unit/runner/basic_test.rb

@@ -0,0 +1,14 @@
+require File.expand_path(File.join(File.dirname(__FILE__), "..", "parser_test_helper"))
+
+class BasicTest < Test::Unit::TestCase
+  
+  def test_restores_original_dir
+    original_dir = Dir.pwd
+    puts "*** #{original_dir}"
+    PDoc::Runner.new("test/fixtures/ajax.js",
+      :output    => 'test/output',
+      :templates => 'templates/html'
+    ).run
+    assert_equal original_dir, Dir.pwd
+  end
+end