test: add unit tests and wire up cookstyle autocorrect

[ramereth]

• Add RSpec test suite (.rspec, spec/spec_helper.rb) with 20 specs:
  • spec/kitchen-sync/version_spec.rb: validate VERSION constant
  • spec/kitchen-sync/checksums_spec.rb: invoke bundled checksums.rb
    against tmpdirs and validate JSON output
  • spec/kitchen-sync/core_ext_spec.rb: cover the ChefBase#init_command
    monkey-patch using a stub ChefBase (test-kitchen 4 no longer ships it)
  • spec/kitchen/transport/{rsync,sftp}_spec.rb: validate transport class
    structure, defaults, and constants
• Add rspec ~> 3.0 development dependency
• Add rake spec task plus test/unit aliases (with desc so they show
  up in rake -T); default task now runs spec then style
• Add unit test job to .github/workflows/lint.yml gated on cookstyle/yamllint
• Apply cookstyle/chefstyle autocorrect across lib/ and gemspec:
  • Switch single-quoted strings to double-quoted
  • Replace deprecated File.exists? with File.exist?
  • Replace "..." % args with format(...)
  • Add unless defined?(...) guards to stdlib requires
  • Fix indentation, guard-clause spacing, and end alignment
  • Freeze mutable string constants
  • Use each_with_object instead of inject returning memo
  • Use $CHILD_STATUS / $INPUT_RECORD_SEPARATOR via English
  • Update copyright header format and bump rubygems source to https
• Drop dead File.directory?(local) no-op left by autocorrect in sftp.rb

Signed-off-by: Lance Albertson lance@osuosl.org

Description

Please describe what this change achieves

Issues Resolved

List any existing issues this PR resolves, or any Discourse or
StackOverflow discussions that are relevant

Type of Change

Our release process assumes you are using Conventional Commit messages.

The most important prefixes you should have in mind are:

• _fix_: which represents bug fixes, and correlates to a SemVer patch.
• _feat_: which represents a new feature, and correlates to a SemVer minor.
• _feat!_:, or fix!:, refactor!:, etc., which represent a breaking change (indicated by the !) and will result in a major version change.

If you have not included a conventional commit message this can be fixed on merge.

Check List

• New functionality includes tests
• All tests pass
• Commit message includes a Conventional Commit Message

[Stromweld]

LGTM, not sure what the require "English" is for in a couple of places. Never seen that one before.

[ramereth]

Good question.

This require is needed because this file logs the rsync exit code using
$CHILD_STATUS.exitstatus. CHILDSTATUS is not a standalone core global; it is
the English alias for CHILD_STATUS, provided by requiring the English standard
library. Without require "English", that alias is not available and this
warning path would break.

Upstream Ruby docs:

• English aliases: https://docs.ruby-lang.org/en/master/English.html
• Global child status: https://ruby-doc.org/3.4.1/globals_rdoc.html#label-24-3F+-28Child+Status-29
• exitstatus on Process::Status: https://ruby-doc.org/3.4.1/Process/Status.html#method-i-exitstatus

If we wanted to drop require "English", we would need to switch this code to
use $?.exitstatus instead.

[Stromweld]

nice good to know thanks