microblog/spec/models/tag_spec.rb

require 'rails_helper'

RSpec.describe Tag, type: :model do
  describe 'HASHTAG_RE' do
    subject { Tag::HASHTAG_RE }

    it 'does not match URLs with anchors with non-hashtag characters' do
      expect(subject.match('Check this out https://medium.com/@alice/some-article#.abcdef123')).to be_nil
    end

    it 'does not match URLs with hashtag-like anchors' do
      expect(subject.match('https://en.wikipedia.org/wiki/Ghostbusters_(song)#Lawsuit')).to be_nil
    end
  end
end