class HasTheMethod
  def self.has_secure_password; end
end

class DoesNotHaveTheMethod
end

RSpec.describe OmniAuth::Identity::SecurePassword do
  it 'extends with the class methods if it does not have the method' do
    expect(DoesNotHaveTheMethod).to receive(:extend).with(OmniAuth::Identity::SecurePassword::ClassMethods)
    DoesNotHaveTheMethod.include OmniAuth::Identity::SecurePassword
  end

  it 'does not extend if the method is already defined' do
    expect(HasTheMethod).not_to receive(:extend)
    HasTheMethod.include OmniAuth::Identity::SecurePassword
  end

  it 'responds to has_secure_password afterwards' do
    [HasTheMethod, DoesNotHaveTheMethod].each do |klass|
      klass.send(:include, OmniAuth::Identity::SecurePassword)
      expect(klass).to be_respond_to(:has_secure_password)
    end
  end
end