Class: OutputToFDMatcher

Inherits:
Object show all
Defined in:
lib/extensions/mspec/mspec/matchers/output_to_fd.rb

Overview

Lower-level output speccing mechanism for a single output stream. Unlike OutputMatcher which provides methods to capture the output, we actually replace the FD itself so that there is no reliance on a certain method being used.

Instance Method Summary collapse

Constructor Details

#initialize(expected, to) ⇒ OutputToFDMatcher

Returns a new instance of OutputToFDMatcher.



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# File 'lib/extensions/mspec/mspec/matchers/output_to_fd.rb', line 9

def initialize(expected, to)
  @to, @expected = to, expected

  case @to
  when STDOUT
    @to_name = "STDOUT"
  when STDERR
    @to_name = "STDERR"
  when IO
    @to_name = @to.object_id.to_s
  else
    raise ArgumentError, "#{@to.inspect} is not a supported output target"
  end
end

Instance Method Details

#failure_message ⇒ Object 



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# File 'lib/extensions/mspec/mspec/matchers/output_to_fd.rb', line 57

def failure_message()
  ["Expected (#{@to_name}): #{@expected.inspect}\n",
   "#{'but got'.rjust(@to_name.length + 10)}: #{@actual.inspect}\nBacktrace"]
end

#matches?(block) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/extensions/mspec/mspec/matchers/output_to_fd.rb', line 33

def matches?(block)
  old_to = @to.dup
  with_tmp do |out|
    # Replacing with a file handle so that Readline etc. work
    @to.reopen out
    begin
      block.call
    ensure
      @to.reopen old_to
      old_to.close
    end

    out.rewind
    @actual = out.read

    case @expected
    when Regexp
      !(@actual =~ @expected).nil?
    else
      @actual == @expected
    end
  end
end

#negative_failure_message ⇒ Object 



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# File 'lib/extensions/mspec/mspec/matchers/output_to_fd.rb', line 62

def negative_failure_message()
  ["Expected output (#{@to_name}) to NOT be:\n", @actual.inspect]
end

#with_tmp ⇒ Object 



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# File 'lib/extensions/mspec/mspec/matchers/output_to_fd.rb', line 24

def with_tmp
  path = tmp("mspec_output_to_#{$$}_#{Time.now.to_i}")
  File.open(path, 'w+') { |io|
    yield(io)
  }
ensure
  File.delete path if path
end