uninitialized constant Mail::TestMailer

前提・実現したいこと

ruby on rails でユーザーがグループ作成時にグループに属するユーザにメールを送りたい

発生している問題・エラーメッセージ

NameError in MailsController#create

uninitialized constant Mail::TestMailer

class NoticeEventMailer < ActionMailer::Base
    default :from => 'any_from_address@example.com'

    def notice_event_email(mail)
        @mail = mail
        mail( :to => @mail.users.email,

該当のソースコード

notice_event_email.erb

class NoticeEventMailer < ActionMailer::Base
    default :from => 'any_from_address@example.com'

    def notice_event_email(mail)
        @mail = mail
        mail( :to => @mail.users.email,
              :subject => 'Notice an Event' )
    end
end

notice_event_mailer.rb

<!DOCTYPE html>
<html>
  <head>
    <meta content='text/html; charset=UTF-8' http-equiv='Content-Type' />
  </head>
  <body>
    <!--メール本文-->
    <h1>タイトル</h1>
    <p><%= @mail.title %></p>
    <h1>本文</h1>
    <p><%= @mail.content %></p>
  </body>
</html>

mails_controller.erb

def create
        @mail = Mail.new(mail_params)
        @mail.user_id = current_user.id
        
        if @mail.save
        NoticeEventMailer.notice_event_email(@mail).deliver
        redirect_to mail_path(@mail)
        else
          @mail = Mail.new
          render :new
        end
    end

environment.erb

ActionMailer::Base.smtp_settings = {
  :user_name => 'your_sendgrid_username',
  :password => 'your_sendgrid_password',
  :domain => 'yourdomain.com',
  :address => 'smtp.sendgrid.net',
  :port => 587,
  :authentication => :plain,
  :enable_starttls_auto => true
}