history_spec.rb

require 'rails_helper'

describe History ,type: :model do
  let(:member){ create(:member) }
  let(:channel){ create(:channel) }
  let(:create_sub){create(:subscription )}
  it 'should be created after subscribe' do
      expect{create_sub}.to change{History.count}.by(1)
  end

  it 'should be created after unsubscribe' do
    create_sub
    expect{create_sub.destroy}.to change{History.count}.by(1)
  end

end