Testing terminal output with RSpec

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When testing Ruby code that prints something to the terminal, you can test that output.
Since RSpec 3.0 there is a very convenient way to do that.

Anything that writes to stdout (like puts or print) can be captured like this:

expect { something }.to output("hello\n").to_stdout

Testing stderr works in a similar fashion:

expect { something }.to output("something went wrogn\n").to_stderr

Hint: Use heredoc to test multi-line output.

expect { something }.to output(<<-MESSAGE.strip_heredoc).to_stdout
  Dear Bob,
  greetings!
  
  Love,
  Alice
MESSAGE
Arne Hartherz
makandra.com
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Last edit
Arne Hartherz
Keywords
console
License
Source code in this card is licensed under the MIT License.

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Posted by Arne Hartherz to makandra dev (2016-07-05 09:11)
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