Add support for have_output* with no arguments

[peagha]

Summary

Allow have_output* matchers to work with no arguments

Details

When using the have_output* matchers they will fail to match if no argument is provided:

expect(last_command_stopped).not_to have_output_in_stdout

The documentation has examples like that:

aruba/lib/aruba/matchers/command/have_output_on_stderr.rb

Lines 13 to 15 in 8d02d98

	# RSpec.describe do
	# it { expect(last_command_started).to have_output_on_stderr }
	# end

aruba/lib/aruba/matchers/command/have_output.rb

Lines 15 to 17 in 8d02d98

	# RSpec.describe do
	# it { expect(last_command_started).to have_output }
	# end

How Has This Been Tested?

RSpec examples were added to cover the changes

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactoring (cleanup of codebase without changing any existing functionality)
• Update documentation

Checklist:

• I've added tests for my code
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

TODO:

• Fix failure message

[peagha]

I've noticed the failure message is not working properly; I'll fix that and push again

[mvz]

Hi @peagha, you seem to have removed the 'motivation and context' section from the pull request template. Can you tell me a little bit more about where you encountered problems with the current behavior?

Also, which version of Aruba are you using?

[peagha]

@mvz thanks for your answer!

The main motivation is that I had a scenario where the command was failing (exit status != 0) and I wanted to have feedback on that. Older versions of Aruba used to print the whole output when using assert_passing_with, like that:

Exit status was 1 but expected it to be 0. Output:
      /Users/peagha/Code/me/forca/bin/forca:5:in `<main>': unhandled exception

In the latest version, when using expect(last_command_stopped).to be_successfully_executed, all I get is:

(...)
expected "forca" to be successfully executed (RSpec::Expectations::ExpectationNotMetError)
(...)

The output is useful to understand why the command wasn't successfully executed, therefore I added to my app:

expect(last_command_stopped).not_to have_output_on_stderr

What would print the STDERR whenever something is wrong. But that doesn't work because have_output_on_stderr expects an argument. That motivated me to change the matcher to work without arguments 😄

I'm using the lates version of Aruba (0.14.8)

[peagha]

I've updated the failure messages code and they should be working now

[luke-hill]

Given you're changing the output of the rspec failure messages (And matchers by extension), we need at the very least 2 rspec message tests (Ideally more)