```ruby
require "rails_helper"

RSpec.describe AdminNotifierMailer, type: :mailer do
  #pending "add some examples to (or delete) #{__FILE__}"
end
```

Add test for notification email
user
```ruby
require "rails_helper"

RSpec.describe AdminNotifierMailer, type: :mailer do

  describe 'Email notification' do
  	let(:matrix) { SubmittedMatrix.new({submitter_name: "John Lennon and Paul McCartney", 
                                      submitter_email: "paul@thebeatles.com", 
                                      display_email: "false",
                                      name: "Help!",
                                      kind: "Other",
                                      notes: "Help, I need somebody.\nHelp, not just anybody.\nHelp, you know I need someone.\nHelp!",
                                      submitter_url: "www.google.com",
                                      submitter_confidentiality: "true",
                                      ip: "127.0.0.1"}) }
    let(:mail) { AdminNotifierMailer.send_matrix_submitted_email(matrix) }

    it 'renders the subject' do
      expect(mail.subject).to eq('[SuiteSparse Matrix Collection] New Matrix Submitted!')
    end

    it 'renders the sender email' do
      expect(mail.body.encoded)
        .to match(/.*paul@thebeatles\.com.*/)
    end
  end
end
```
assistant