```ruby
require File.expand_path('../../../../spec_helper', __FILE__)

process_is_foreground do
  with_feature :readline do
    require 'readline'

    describe "Readline::HISTORY.[]=" do
      before(:each) do
        Readline::HISTORY.push("1", "2", "3")
      end

      after(:each) do
        Readline::HISTORY.pop
        Readline::HISTORY.pop
        Readline::HISTORY.pop
      end

      it "returns the new value for the passed index" do
        (Readline::HISTORY[1] = "second test").should == "second test"
      end

      it "raises an IndexError when there is no item at the passed positive index" do
        lambda { Readline::HISTORY[10] = "test" }.should raise_error(IndexError)
      end

      it "sets the item at the given index" do
        Readline::HISTORY[0] = "test"
        Readline::HISTORY[0].should == "test"

        Readline::HISTORY[1] = "second test"
        Readline::HISTORY[1].should == "second test"
      end

      it "raises an IndexError when there is no item at the passed negative index" do
        lambda { Readline::HISTORY[10] = "test" }.should raise_error(IndexError)
      end
    end
  end
end
```

Make Readline::HISTORY.[]= spec test return value
user
```ruby
require File.expand_path('../../../../spec_helper', __FILE__)

process_is_foreground do
  with_feature :readline do
    require 'readline'

    describe "Readline::HISTORY.[]=" do
      before(:each) do
        Readline::HISTORY.push("1", "2", "3")
      end

      after(:each) do
        Readline::HISTORY.pop
        Readline::HISTORY.pop
        Readline::HISTORY.pop
      end

      it "returns the new value for the passed index" do
        Readline::HISTORY.[]=(1, "second test").should == "second test"
      end

      it "raises an IndexError when there is no item at the passed positive index" do
        lambda { Readline::HISTORY[10] = "test" }.should raise_error(IndexError)
      end

      it "sets the item at the given index" do
        Readline::HISTORY[0] = "test"
        Readline::HISTORY[0].should == "test"

        Readline::HISTORY[1] = "second test"
        Readline::HISTORY[1].should == "second test"
      end

      it "raises an IndexError when there is no item at the passed negative index" do
        lambda { Readline::HISTORY[10] = "test" }.should raise_error(IndexError)
      end
    end
  end
end
```
assistant