def expect_json(
  ok = true,
  http = 200
)
  expect(last_response.header['Content-Type']).to eq('application/json')

  if (ok == true) then
    expect(JSON.parse(last_response.body)['ok']).to eq(true)
  else
    expect(JSON.parse(last_response.body)['ok']).to eq(false)
  end

  expect(last_response.status).to eq(http)
end