thoughtbot--shoulda-matchers/spec/support/unit/helpers/active_model_versions.rb

RSpec.configure do |c|
  def active_model_3_1?
    (::ActiveModel::VERSION::MAJOR == 3 && ::ActiveModel::VERSION::MINOR >= 1) || active_model_4_0?
  end

  def active_model_3_2?
    (::ActiveModel::VERSION::MAJOR == 3 && ::ActiveModel::VERSION::MINOR >= 2) || active_model_4_0?
  end

  def active_model_4_0?
    ::ActiveModel::VERSION::MAJOR == 4
  end
end