RSPEC - PUT request return error 405

i have this test

describe 'PUT #start' do
  before do
    put :start, abtest_id: @variation.abtest.id.to_s,
                variation_id: @variation.id.to_s, format: 'json'
  end

  it "shoud return HTTP 200 status code" do
    expect(response.response_code).to eql(200)
  end
end

This is the response

Failure/Error: expect(response.response_code).to eql(200)

   expected: 200
        got: 405

   (compared using eql?)

I can't make put request with rspec. Someone would have an alternative to test it?