Add tests for HighLine::Simulator - Issue #142

As suggested by @bparanj on #142

test/tc_simulator.rb

@@ -0,0 +1,23 @@
+require 'test/unit'
+require 'highline/import'
+require 'highline/simulate'
+
+class SimulatorTest < Test::Unit::TestCase
+  def setup
+    input     = StringIO.new
+    output    = StringIO.new
+    $terminal = HighLine.new(input, output)
+  end
+
+  def test_simulator
+    HighLine::Simulate.with('Bugs Bunny', '18') do
+      name = ask('What is your name?')
+
+      assert_equal 'Bugs Bunny', name
+
+      age = ask('What is your age?')
+
+      assert_equal '18', age
+    end
+  end
+end