I was passing all the specs except for this one. Then I realized that my num_near_matches method was wrong even though it was passing the specs. Everything started working fine after I corrected my num_near_matches method. Read this post to learn more about the error.
Add the following rspec code to the num_near_matches method and try to pass the test.
it "should not count a matched peg with a correct colored peg in a different position" do expect(code.num_near_matches(Code.new(["G", "G", "R", "B"]))).to eq(0) end
Hope this helps