RSpec类型错误-没有将字符串转换为整数的隐式转换

I'm trying to make a test green and I'm getting this error. Even when I pry the code it shows that a string is being returned so I have no idea why the test won't green. Here is my test and error for clarification. I'm assuming this is a common error for folks.I'm trying to make a test green and I'm getting