Basic Assert

A basic, customizable assertion library for lightweight pre and post-conditions checking.

Installation

Just add this line to your application's Gemfile:

gem 'basic_assert'

What's this for ?

TODO: add rationale

Usage

In order to use this library you need to include an asserter and a raiser in the current self context.

In, say, a Rails project, you may just add an initializer like

class Object
  case Rails.configuration.assert_mode
  when :raise
    include BasicAssert::ExceptionRaiser
    include BasicAssert::BasicAsserter
  else # :ignore
    include BasicAssert::NoopAsserter
  end
end

or define your own asserting policies and side effects, or override them for the given self where appropriate.

Then, you may add you're precondition checks accordingly:

# plain variants:
assert condition
assert condition, message

# block variants, the asserter tells when/if the condition gets evaluated:
assert { condition block }
assert(message) { condition block } 

An asserter is a concern exposing an assert() function responsible of evaluating the given condition; a raiser is a concern exposing an assert_raise() function responsible of managing the actual condition failure.

Currently, the following asserters and raisers are defined:

• BasicAsserter: exposes plain and block versions, with or without message
• NoopAsserter: does nothing, blocks are never evaluated in this case
• ExceptionRaiser: raises an ExceptionRaiser::AssertionException; this extends Exception and should not be rescued by user code.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/maxjanes/basic_assert.

License

The gem is available as open source under the terms of the MIT License.