require File.expand_path('../../../spec_helper', __FILE__)
require File.expand_path('../fixtures/classes', __FILE__)

describe "IO.try_convert" do
  ruby_version_is "1.8.8" do
    before :each do
      @name = tmp("io_try_convert.txt")
      @io = new_io @name
    end

    after :each do
      @io.close unless @io.closed?
      rm_r @name
    end

    it "returns the passed IO object" do
      IO.try_convert(@io).should equal(@io)
    end

    it "does not call #to_io on an IO instance" do
      @io.should_not_receive(:to_io)
      IO.try_convert(@io)
    end

    it "calls #to_io to coerce an object" do
      obj = mock("io")
      obj.should_receive(:to_io).and_return(@io)
      IO.try_convert(obj).should equal(@io)
    end

    it "returns nil when the passed object does not respond to #to_io" do
      IO.try_convert(mock("io")).should be_nil
    end

    it "raises a TypeError if the object does not return an IO from #to_io" do
      obj = mock("io")
      obj.should_receive(:to_io).and_return("io")
      lambda { IO.try_convert(obj) }.should raise_error(TypeError)
    end

    it "propagates an exception raised by #to_io" do
      obj = mock("io")
      obj.should_receive(:to_io).and_raise(TypeError.new)
      lambda{ IO.try_convert(obj) }.should raise_error(TypeError)
    end
  end
end
