Testing rendering of a given layout with RSpec & Rails

Question

Is it possible to test the use of a given layout using RSpec with Rails, for example I\'d like a matcher that does the following:

response.should use_layout(         


        

Answer 1

Here's a version of dmcnally's code that allows no arguments to be passed, making "should use_layout" and "should_not use_layout" work (to assert that the controller is using any layout, or no layout, respectively - of which I would expect only the second to be useful as you should be more specific if it is using a layout):

class UseLayout
   def initialize(expected = nil)
     if expected.nil?
       @expected = nil
     else
       @expected = 'layouts/' + expected
     end
   end
   def matches?(controller)
     @actual = controller.layout
     #@actual.equal?(@expected)
     if @expected.nil?
       @actual
     else
       @actual == @expected
     end
   end
   def failure_message
     if @expected.nil?
       return 'use_layout expected a layout to be used, but none was', 'any', @actual
     else
       return "use_layout expected #{@expected.inspect}, got #{@actual.inspect}", @expected, @actual
     end
   end
   def negative_failure_message
     if @expected.nil?
       return "use_layout expected no layout to be used, but #{@actual.inspect} found", 'any', @actual
     else
       return "use_layout expected #{@expected.inspect} not to equal #{@actual.inspect}", @expected, @actual
     end
   end
end


def use_layout(expected = nil)
   UseLayout.new(expected)
end