Minitest::ShouldJustWork

Classic RSpec-like .should / .should_not comparisons for Minitest.

book.title.should == "Revolution"

That is the whole idea. The gem monkey-patches Object so that comparison operators after .should turn into plain Minitest assertions.

(Ouch! Monkey patch? Yes! But it only defines Object#should and #should_not.)

Requires Ruby >= 3.1. Tested against Minitest 5 and Minitest 6.

Installation

Add it to your application's Gemfile:

group :test do
  gem 'minitest-spec-rails'
  gem 'minitest-should_just_work'
end

$ bundle

Usage

require 'minitest/autorun'
require 'minitest/should_just_work'

describe "Books" do
  it "should work" do
    book = Book.new title: "Revolution"

    book.title.should == "Revolution"
  end
end

Comparisons

Minitest::ShouldJustWork	Minitest::Assertions
`x.should == y`	`assert_equal y, x`
`x.should == nil`	`assert_nil x`
`x.should != y`	`refute_equal y, x`
`x.should != nil`	`refute_nil x`
`x.should =~ /y/`	`assert_match /y/, x`
`x.should > y`	`assert_operator x, :>, y`
`x.should < y`	`assert_operator x, :<, y`
`x.should >= y`	`assert_operator x, :>=, y`
`x.should <= y`	`assert_operator x, :<=, y`

Note that x.should == nil asserts nil rather than equality with nil. Minitest 5 deprecates assert_equal nil, x and Minitest 6 fails it outright, so this is the only spelling that can work.

Negating

Use should_not, or should.not, to turn any comparison into its refute_:

  obj.should_not == 3                # => refute_equal 3, obj
  obj.should_not =~ /regex/          # => refute_match /regex/, obj
  obj.should_not == nil              # => refute_nil obj

Exceptions and throws

  should.raise ZeroDivisionError do
    2 / 0
  end

  should_not.raise ZeroDivisionError do
    2 / 1
  end

  should.throw(:done) { throw :done }
  should_not.throw(:done) { keep_going }

should.raise with no argument catches StandardError.

RuboCop

obj.should == 2 is a statement whose value is discarded, and obj.should == nil compares against nil on purpose. Three cops object to exactly that, so switch them off for your tests:

Lint/Void:
  Exclude:
    - test/**/*
Style/NilComparison:
  Exclude:
    - test/**/*
Style/NonNilCheck:
  Exclude:
    - test/**/*

Ruby's own -w will also report "useless use of == in void context" for every line, so leave warnings off for your test task.

Development

$ bin/setup
$ bundle exec rake        # tests and RuboCop

To run the suite against a particular Minitest line:

$ MINITEST_VERSION="~> 5.0" bundle install && MINITEST_VERSION="~> 5.0" bundle exec rake test

Acknowledgements & licensing

Inspired by the minitest-should_syntax gem.