ruby-on-rails - 仅当特定实例变量具有值时，如何 stub 实例方法？

Question

我有一个对象MyObject:

class MyObject

  def initialize(options = {})
    @stat_to_load = options[:stat_to_load] || 'test'
  end

  def results
   []
  end
end

仅当 stat_to_load = "times" 时，我才想 stub results 方法。我怎样才能做到这一点？我试过了:

MyObject.any_instance.stubs(:initialize).with({
  :stat_to_load => "times"
}).stubs(:results).returns(["klala"])

但它不起作用。有什么想法吗？

Answer 1

因此，我认为可能有一种更简单的方法来测试您要测试的内容，但如果没有更多上下文，我不知道该推荐什么。但是，这里有一些概念验证代码可以表明您可以完成您想要做的事情:

describe "test" do
  class TestClass
    attr_accessor :opts
    def initialize(opts={})
      @opts = opts
    end

    def bar
      []
    end
  end
  let!(:stubbed) do
    TestClass.new(args).tap{|obj| obj.stub(:bar).and_return("bar")}
  end
  let!(:unstubbed) { TestClass.new(args) }

  before :each do
    TestClass.stub(:new) do |args|
      case args
      when { :foo => "foo" }
        stubbed
      else
        unstubbed
      end
    end
  end

  subject { TestClass.new(args) }

  context "special arguments" do
    let(:args) { { :foo => "foo" } }
    its(:bar) { should eq "bar" }
    its(:opts) { should eq({ :foo => "foo" }) }
  end

  context "no special arguments" do
    let(:args) { { :baz => "baz" } }
    its(:bar) { should eq [] }
    its(:opts) { should eq({ :baz => "baz" }) }
  end

end

---

test
  special arguments
    bar
      should == bar
    opts
      should == {:foo=>"foo"}
  no special arguments
    bar
      should == []
    opts
      should == {:baz=>"baz"}

Finished in 0.01117 seconds
4 examples, 0 failures

不过，我在这里大量使用了特殊的主题/让上下文 block 。参见 http://benscheirman.com/2011/05/dry-up-your-rspec-files-with-subject-let-blocks/有关该主题的更多信息。