在Cloud9上使用Rspec：找不到文件

Question

我是Ruby新手，尝试使用Cloud9 IDE测试以下代码：

require 'rspec'
require_relative '../calculator'

describe Calculator do
  before { @calculator = Calculator.new('Rspec calculator')}

  it "should add 2 numbers correctly" do
    expect(@calculator.add(2,2)).to eq 4
  end

  it "should subtract 2 numbers correctly" do
    expect(@calculator.subtract(4, 2)).to eq 2
  end
end

使用：tsa：〜/ workspace $ rspec spec / calculator_spec.rb

这些是结果：

An error occurred while loading ./spec/calculator_spec.rb.
Failure/Error: require_relative '../calculator'

LoadError:
  cannot load such file -- /home/ubuntu/workspace/calculator
# ./spec/calculator_spec.rb:2:in `require_relative'
# ./spec/calculator_spec.rb:2:in `<top (required)>'
No examples found.

Finished in 0.00033 seconds (files took 0.14093 seconds to load)
0 examples, 0 failures, 1 error occurred outside of examples

我非常感谢您对新手友好的建议。 谢谢，Tsa