IO::Grab

Capture IO writes.

Installation

Add this line to your application's Gemfile:

gem 'io-grab', require: false

And then execute:

$ bundle

Or install it yourself as:

$ gem install io-grab

Usage

io-grab adds #grab method to IO. (It also extends StringIO for consistency, even though it isn't really an IO.) You can use this method to temporarily redirect writes to the object to a string, ie. for later examination.

require 'io/grab'

STDOUT.grab { puts "foo" }
# _ == "foo\n"

This is particularly useful for testing, eg. to check for expected messages.

describe "Kernel#puts" do
  it "adds a newline at the end" do
    STDOUT.grab { puts "foo" }.should =~ /\n\z/
  end
end

Contributing

We welcome contributions of all kinds to this repository. For instructions on how to get started and descriptions of our development workflows, please see our contributing guide.