```ruby
require 'spec_helper'

describe(Jekyll::Converters::CoffeeScript) do
  let(:configuration) { Jekyll::Configuration::DEFAULTS }
  let(:converter) do
    Jekyll::Converters::CoffeeScript.new(configuration)
  end
  let(:coffeescript_content) do
    <<-COFFEESCRIPT
# Functions:
square = (x) -> x * x

# Arrays:
list = [1, 2, 3, 4, 5]

# Objects:
math =
  root:   Math.sqrt
  square: square
  cube:   (x) -> x * square x
COFFEESCRIPT
  end
  let(:js_content) do
    <<-JS
(function() {
  var list, math, square;

  square = function(x) {
    return x * x;
  };

  list = [1, 2, 3, 4, 5];

  math = {
    root: Math.sqrt,
    square: square,
    cube: function(x) {
      return x * square(x);
    }
  };

}).call(this);
JS
  end

  context "matching file extensions" do
    it "matches .coffee files" do
      expect(converter.matches(".coffee")).to be_true
    end
  end

  context "determining the output file extension" do
    it "always outputs the .js file extension" do
      expect(converter.output_ext(".always-js-dont-matter")).to eql(".js")
    end
  end

  context "converting CoffeeScript" do
    it "produces JS" do
      expect(converter.convert(coffeescript_content)).to eql(js_content)
    end
  end

end
```

Use be(true) in spec because be_true has changed.
user
```ruby
require 'spec_helper'

describe(Jekyll::Converters::CoffeeScript) do
  let(:configuration) { Jekyll::Configuration::DEFAULTS }
  let(:converter) do
    Jekyll::Converters::CoffeeScript.new(configuration)
  end
  let(:coffeescript_content) do
    <<-COFFEESCRIPT
# Functions:
square = (x) -> x * x

# Arrays:
list = [1, 2, 3, 4, 5]

# Objects:
math =
  root:   Math.sqrt
  square: square
  cube:   (x) -> x * square x
COFFEESCRIPT
  end
  let(:js_content) do
    <<-JS
(function() {
  var list, math, square;

  square = function(x) {
    return x * x;
  };

  list = [1, 2, 3, 4, 5];

  math = {
    root: Math.sqrt,
    square: square,
    cube: function(x) {
      return x * square(x);
    }
  };

}).call(this);
JS
  end

  context "matching file extensions" do
    it "matches .coffee files" do
      expect(converter.matches(".coffee")).to be(true)
    end
  end

  context "determining the output file extension" do
    it "always outputs the .js file extension" do
      expect(converter.output_ext(".always-js-dont-matter")).to eql(".js")
    end
  end

  context "converting CoffeeScript" do
    it "produces JS" do
      expect(converter.convert(coffeescript_content)).to eql(js_content)
    end
  end

end
```
assistant