Question

我是rails和rspec的新手，目前正在线上学习。

在本教程中，我运行以下代码：

def display_board(board)
  puts " #{board[0]} | #{board[1]} | #{board[2]} "
  puts "-----------"
  puts " #{board[3]} | #{board[4]} | #{board[5]} "
  puts "-----------"
  puts " #{board[6]} | #{board[7]} | #{board[8]} "
end

board = [" "," "," "," "," "," "," "," "," "]
display_board(board)

当我运行测试时，我得到以下输出：

/lib/display_board.rb
  defines a method display_board
  #display_board method
    represents a cell as a string with 3 spaces (FAILED - 1) 

Failures: 

  1) /lib/display_board.rb #display_board method represents a cell as a string with 3 spaces

     Failure/Error:
       def display_board(board)
         puts " #{board[0]} | #{board[1]} | #{board[2]} "
         puts "-----------"
         puts " #{board[3]} | #{board[4]} | #{board[5]} "
         puts "-----------"
         puts " #{board[6]} | #{board[7]} | #{board[8]} "
       end

     ArgumentError:
       wrong number of arguments (0 for 1)
     # ./lib/display_board.rb:2:in `display_board'
     # ./spec/display_board_spec.rb:10:in `block (4 levels) in <top (required)>' 
     # ./spec/spec_helper.rb:5:in `capture_puts'
     # ./spec/display_board_spec.rb:10:in `block (3 levels) in <top (required)>'

Finished in 0.00296 seconds (files took 0.14604 seconds to load)

2 examples, 1 failure

Failed examples:

rspec ./spec/display_board_spec.rb:9 # /lib/display_board.rb #display_board method represents a cell as a string with 3 spaces

测试用例如下：

it 'represents a cell as a string with 3 spaces' do
  output = capture_puts{ display_board }
  expect(output).to include("   ")
end

第10行是规范文件是“output = capture_puts {display_board}”

“capture_puts”在spec_helpr.rb中定义如下：

def capture_puts
  begin
    old_stdout = $stdout
    $stdout = StringIO.new('','w')
    yield
    $stdout.string
  ensure
    $stdout = old_stdout
  end
end

我搜索了错误“错误的参数数量（0表示1）”，但我没有得到任何有用的结果。请建议，因为我真的是Ruby和Rails的初学者。

Answer 1

您必须将董事会传递给display_board

board = [" "," "," "," "," "," "," "," "," "]
output = capture_puts{ display_board(board) }
expect(output).to include("   ")

Answer 2

错误是由于这一行

output = capture_puts{ display_board }

display_board需要一个参数，所以看起来应该是

output = capture_puts{ display_board(board) }

我还想指出，有一个用于测试stdout的rspec匹配器。

https://www.relishapp.com/rspec/rspec-expectations/docs/built-in-matchers/output-matcher

Rails rspec错误：参数数量错误（0表示1）

2 个答案: