Minitest::ShouldJustWork

Classic Rspec-like .should/.should_not matching for MiniTest.

This gem is heavely inspired from the minitest-should_syntax gem, what has not updated a long time. Therefore we need this new gem to support .should syntax.

minitest-should_just_work lets you use a syntax similar to classic RSpec on your MiniTest tests. It monkey-patches Object to translate RSpec-like sugar into plain MiniTest assert matchers.

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

Installation

Install the gem and add to the application's Gemfile by executing:

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

Then you may use it as so:

  obj.should == 2                    # => assert_equal 2, obj
  obj.should =~ /regex/              # => assert_match /regex/, obj
  obj.should != 3                    # => assert_not_equal 3, obj
  obj.should.nil                     # => assert_nil obj
  obj.should.respond_to(:freeze)     # => assert_respond_to obj, :freeze 

# Note that .be, .a and .an are optional.
  obj.should.nil                     # => assert_nil obj
  obj.should.be.nil                  # => assert_nil obj
  obj.should.be.a.nil                # => assert_nil obj

# Use `should.not` instead `should` to negate any comparison.
  obj.should.not == 3                # => refute_equal 3, obj
  obj.should.not =~ /regex/          # => refute_match obj, regex
  obj.should.not.be.nil              # => refute obj.nil?

# Anything else will pass through with a ?:
  obj.should.be.good_looking         # => assert obj.good_looking?

# Testing exceptions:
  should.raise ZeroDivisionError do
    2/0
  end

Wrapped assertions

These are based on MiniTest::Assertions.

MiniTest::ShouldJustWork	MiniTest::Assertions
x.should.equal y	assert_equal x, y
x.should == y	assert_equal x, y
x.should.not.equal	refute_equal x, y
x.should !=	refute_equal x, y
x.should.be	assert_same x, y
x.should.not.be	refute_same x, y
x.should >= (and others)	assert_operator x, :>=, y
x.should.not >= (and others)	refute_operator x, :>=, y
x.should.be.nil	assert_nil x
x.should.not.be.nil	refute_nil x
x.should.be.close y	assert_in_delta y
x.should.be.in_epsilon y	assert_in_epsilon y
x.should.match /y/	assert_match x, /y/
x.should =~ /y/	assert_match x, /y/
x.should.not.match, should.not =~	refute_match
x.should.be.an.instance_of y	assert_instance_of x, y
x.should.be.a.kind_of x, y	assert_kind_of x, y
x.should.respond_to :y	assert_respond_to x, :y
should.raise(x) { ... }	assert_raise(x) { ... }
should.throw(x) { ... }	assert_throws(x) { ... }
should.satisfy { ... }	assert_block { ... }

Messages

Use the otherwise helper:

it "should work" do
  book = Book.new title: "Pride & Prejudice"

  otherwise "The title should've been set on constructor"
  book.title.should == "Pride & Prejudice"
end

Result:

1) Failure:
should work(Test) [your_test.rb:77]:
The title should've been set on constructor.
Expected: "Pride & Prejudice"
  Actual: nil

Or you can use .blaming which does the same thing (with a more cumbersome syntax):

it "should work" do
  book = Book.new title: "Pride & Prejudice"

  message = "The title should've been set on constructor"
  book.title.should.blaming(message) == "Pride & Prejudice"
end

Extending

Need to create your own matchers? Create your new matcher in a module, then use MiniTest::ShouldJustWork.add.

module DanceMatcher
  def boogie_all_night!
    # Delegates to `assert(condition, message)`.
    #
    #   positive?   - returns `true` if .should, or `false` if .should.not
    #   test        - the MiniTest object
    #   msg         - the failure message. `nil` if not set
    #
    if positive?
      test.assert left.respond_to?(:dance), msg
    else
      test.refute left.respond_to?(:dance), msg
    end
  end
end

MiniTest::ShouldJustWork.add DanceMatcher

# Then in your tests, use:
dancer.should.boogie_all_night!

Acknowledgements & licensing

(c) 2022 Priit Tark, MIT license (c) 2013 Rico Sta. Cruz, MIT license