denchr denchr - 2 months ago 13
Ruby Question

suppresing output to console with ruby

I am writing some unit tests like the following:

def executing_a_signal
a_method(a_signal.new, a_model, a_helper);
assert_equal(new_state, a_model.state)
end


The tests work fine, but the method which runs just before the assertion to execute the logic prints various messages to the console, mainly via
puts
.

Is there a quick, perhaps built-in, way to suppress that output to the console? I am only interested in the final effect of the method on the model object, and for the sake of keeping the console clean basically, I was hoping to find a way to simply prevent all output to the console without re-writing or commenting out those
puts
statements just for my tests.

It is definitely not a critical issue, but would very much like to hear any thoughts or ideas (or workaround) on it.

Answer

I use the following snippet in tests to capture and test STDOUT

def capture_stdout(&block)
  original_stdout = $stdout
  $stdout = fake = StringIO.new
  begin
    yield
  ensure
    $stdout = original_stdout
  end
  fake.string
end

With this method, the above would become:

def executing_a_signal
  capture_stdout { a_method(a_signal.new, a_model, a_helper) }
  assert_equal(new_state, a_model.state)
end
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