diff --git a/spec/models/ticket/article_spec.rb b/spec/models/ticket/article_spec.rb
index 9dce6b42c..888682f0a 100644
--- a/spec/models/ticket/article_spec.rb
+++ b/spec/models/ticket/article_spec.rb
@@ -57,6 +57,37 @@ RSpec.describe Ticket::Article, type: :model do
       end
     end
 
+    describe 'DoS protection:' do
+      context 'when #body exceeds 1.5MB' do
+        subject(:article) { create(:ticket_article, body: body) }
+        let(:body) { 'a' * 2_000_000 }
+
+        context 'for "web" thread', application_handle: 'web' do
+          it 'raises an Unprocessable Entity error' do
+            expect { article }.to raise_error(Exceptions::UnprocessableEntity)
+          end
+        end
+
+        context 'for "test.postmaster" thread', application_handle: 'test.postmaster' do
+          it 'truncates body to 1.5 million chars' do
+            expect(article.body.length).to eq(1_500_000)
+          end
+
+          context 'with NULL bytes' do
+            let(:body) { "\u0000" + 'a' * 2_000_000 }
+
+            it 'still removes them, if necessary (postgres doesn’t like them)' do
+              expect(article).to be_persisted
+            end
+
+            it 'still truncates body' do
+              expect(article.body.length).to eq(1_500_000)
+            end
+          end
+        end
+      end
+    end
+
     describe 'Cti::Log syncing:' do
       context 'with existing Log records' do
         context 'for an incoming call from an unknown number' do
diff --git a/test/unit/ticket_article_dos_test.rb b/test/unit/ticket_article_dos_test.rb
deleted file mode 100644
index 0cb816b6c..000000000
--- a/test/unit/ticket_article_dos_test.rb
+++ /dev/null
@@ -1,108 +0,0 @@
-require 'test_helper'
-
-class TicketArticleDos < ActiveSupport::TestCase
-
-  def two_mio_random_chars
-    @two_mio_random_chars ||= Array.new(2_000_000) { [*'0'..'9', *'a'..'z', ' ', ' ', ' ', '. '].sample }.join
-  end
-
-  test 'check body size' do
-
-    org_community = Organization.create_if_not_exists(
-      name: 'Zammad Foundation',
-    )
-    user_community = User.create_or_update(
-      login:           'article.dos@example.org',
-      firstname:       'Article',
-      lastname:        'Dos',
-      email:           'article.dos@example.org',
-      password:        '',
-      active:          true,
-      roles:           [ Role.find_by(name: 'Customer') ],
-      organization_id: org_community.id,
-      updated_by_id:   1,
-      created_by_id:   1,
-    )
-
-    UserInfo.current_user_id = user_community.id
-    ApplicationHandleInfo.current = 'test.postmaster'
-
-    ticket1 = Ticket.create!(
-      group_id:      Group.first.id,
-      customer_id:   user_community.id,
-      title:         'DoS 1!',
-      updated_by_id: 1,
-      created_by_id: 1,
-    )
-    article1 = Ticket::Article.create!(
-      ticket_id:     ticket1.id,
-      type_id:       Ticket::Article::Type.find_by(name: 'phone').id,
-      sender_id:     Ticket::Article::Sender.find_by(name: 'Customer').id,
-      from:          'Zammad Feedback <feedback@example.org>',
-      body:          two_mio_random_chars,
-      internal:      false,
-      updated_by_id: 1,
-      created_by_id: 1,
-    )
-    assert_equal(1_500_000, article1.body.length)
-
-    ticket2 = Ticket.create!(
-      group_id:      Group.first.id,
-      customer_id:   user_community.id,
-      title:         'DoS 2!',
-      updated_by_id: 1,
-      created_by_id: 1,
-    )
-    article2 = Ticket::Article.create!(
-      ticket_id:     ticket2.id,
-      type_id:       Ticket::Article::Type.find_by(name: 'phone').id,
-      sender_id:     Ticket::Article::Sender.find_by(name: 'Customer').id,
-      from:          'Zammad Feedback <feedback@example.org>',
-      body:          "\u0000#{two_mio_random_chars}",
-      internal:      false,
-      updated_by_id: 1,
-      created_by_id: 1,
-    )
-    assert_equal(1_500_000, article2.body.length)
-
-    ApplicationHandleInfo.current = 'web'
-
-    ticket3 = Ticket.create!(
-      group_id:      Group.first.id,
-      customer_id:   user_community.id,
-      title:         'DoS 3!',
-      updated_by_id: 1,
-      created_by_id: 1,
-    )
-
-    assert_raises(Exceptions::UnprocessableEntity) do
-      article3 = Ticket::Article.create!(
-        ticket_id:     ticket3.id,
-        type_id:       Ticket::Article::Type.find_by(name: 'phone').id,
-        sender_id:     Ticket::Article::Sender.find_by(name: 'Customer').id,
-        from:          'Zammad Feedback <feedback@example.org>',
-        body:          "\u0000#{two_mio_random_chars}",
-        internal:      false,
-        updated_by_id: 1,
-        created_by_id: 1,
-      )
-    end
-
-  end
-
-  test 'check body size / cut if email' do
-
-    email_raw_string = <<-MAIL.strip_indent
-      From: me@example.com
-      To: customer@example.com
-      Subject: some new subject
-
-      Some Text#{two_mio_random_chars}
-    MAIL
-
-    ticket_p, article_p, user_p, mail = Channel::EmailParser.new.process({}, email_raw_string)
-    assert_equal(1_500_000, article_p.body.length)
-
-  end
-
-end