Add the Cucumber::Formatter::Interceptor::Pipe class for transparentl…

…y intercepting writes to pipes

This will ultimately be used to consume $stderr and $stdout for formatters

lib/cucumber/formatter/interceptor.rb

@@ -0,0 +1,23 @@
+
+module Cucumber
+  module Formatter
+    module Interceptor
+      class Pipe
+        attr_reader :pipe, :buffer
+        def initialize(pipe)
+          @pipe = pipe
+          @buffer = []
+        end
+
+        def write(str)
+          @buffer << str
+          return @pipe.write(str)
+        end
+
+        def method_missing(method, *args, &blk)
+          @pipe.send(method, *args, &blk)
+        end
+      end
+    end
+  end
+end

spec/cucumber/formatter/interceptor_spec.rb

@@ -0,0 +1,38 @@
+require 'spec_helper'
+require 'cucumber/formatter/interceptor'
+
+module Cucumber::Formatter
+  describe Interceptor::Pipe do
+    let(:pipe) do
+      pipe = double('original pipe')
+      pipe.stub(:instance_of?).and_return(true)
+      pipe
+    end
+
+    describe '#write' do
+      let(:buffer) { 'Some stupid buffer' }
+      let(:pi) { Interceptor::Pipe.new(pipe) }
+
+      it 'should write arguments to the original pipe' do
+        pipe.should_receive(:write).with(buffer).and_return(buffer.size)
+        pi.write(buffer).should == buffer.size
+      end
+
+      it 'should add the buffer to its stored output' do
+        pipe.stub(:write)
+        pi.write(buffer)
+        pi.buffer.should_not be_empty
+        pi.buffer.first.should == buffer
+      end
+    end
+
+    describe '#method_missing' do
+      let(:pi) { Interceptor::Pipe.new(pipe) }
+
+      it 'should pass #tty? to the original pipe' do
+        pipe.should_receive(:tty?).and_return(true)
+        pi.tty?.should be true
+      end
+    end
+  end
+end