Tests for an implementation of the Merge Sort algorithm in Ruby

merge_sort.spec.rb

require 'minitest/autorun'
require './merge_sort'

describe MergeSort do
  before do
    @merge_sort = MergeSort.new
  end

  describe "#sort" do
    it "should sort an array of 1 element" do
      assert_equal(@merge_sort.sort([1]), [1])
    end

    it "should sort an array of multiple elements" do
      assert_equal(@merge_sort.sort([5, 2, 7, 8, 9, 3]),  [2, 3, 5, 7, 8, 9])
    end

    it "should sort an array of multiple elements with equal slots" do
      assert_equal(@merge_sort.sort([5, 5, 1, 3, 3, 7]),  [1, 3, 3, 5, 5, 7])
    end

    it "should sort an array of multiple elements with negative numbers" do
      assert_equal(@merge_sort.sort([-1, -4, 2, 0, -2, 7]),  [-4, -2, -1, 0, 2, 7])
    end

    it "should sort an array of odd length" do
      assert_equal(@merge_sort.sort([8, 3, 6, 2, 6, 8, 0]),  [0, 2, 3, 6, 6, 8, 8])
    end
  end
end

The Merge Sort class being tested can be found here: https://gist.github.com/diegocasmo/b330010bd891c5581ee257f9aac87419