Update Threat Monitoring Alert to generate valid link

app/presenters/alert_management/alert_presenter.rb

@@ -112,3 +112,5 @@ module AlertManagement
     end
   end
 end
+
+AlertManagement::AlertPresenter.prepend_if_ee('EE::AlertManagement::AlertPresenter')

ee/app/presenters/ee/alert_management/alert_presenter.rb

+# frozen_string_literal: true
+
+module EE
+  module AlertManagement
+    module AlertPresenter
+      extend ActiveSupport::Concern
+
+      def details_url
+        return threat_monitoring_alert_project_threat_monitoring_url(project, alert.iid) if alert.threat_monitoring?
+
+        super
+      end
+    end
+  end
+end

ee/changelogs/unreleased/323240-generate-link-to-threat-management-alert.yml

+---
+title: Create link to Threat Monitoring Alert for threat management alerts
+merge_request: 59724
+author:
+type: fixed

ee/config/routes/project.rb

@@ -40,7 +40,7 @@ constraints(::Constraints::ProjectUrlConstrainer.new) do
         resources :subscriptions, only: [:create, :destroy]
 
         resource :threat_monitoring, only: [:show], controller: :threat_monitoring do
-          get '/alerts/:id', action: 'alert_details', constraints: { id: /\d+/ }
+          get '/alerts/:id', action: 'alert_details', constraints: { id: /\d+/ }, as: :threat_monitoring_alert
           resources :policies, only: [:new, :edit], controller: :threat_monitoring
         end
 

ee/spec/presenters/alert_management/alert_presenter_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe AlertManagement::AlertPresenter do
+  let_it_be(:project) { create(:project) }
+  let_it_be(:payload) do
+    {
+      'title' => 'Alert title',
+      'start_time' => '2020-04-27T10:10:22.265949279Z',
+      'custom' => {
+        'alert' => {
+          'fields' => %w[one two]
+        }
+      },
+      'yet' => {
+        'another' => 73
+      }
+    }
+  end
+
+  let_it_be(:alert) { create(:alert_management_alert, :threat_monitoring, project: project, payload: payload) }
+
+  subject(:presenter) { described_class.new(alert) }
+
+  describe '#issue_description' do
+    let(:markdown_line_break) { '  ' }
+
+    subject { presenter.issue_description }
+
+    context 'with threat monitoring alert' do
+      it do
+        is_expected.to eq(
+          <<~MARKDOWN.chomp
+            **Start time:** #{presenter.start_time}#{markdown_line_break}
+            **Severity:** #{presenter.severity}#{markdown_line_break}
+            **GitLab alert:** http://localhost/#{project.full_path}/-/threat_monitoring/alerts/#{alert.iid}
+
+          MARKDOWN
+        )
+      end
+    end
+  end
+
+  describe '#details_url' do
+    context 'when alert has threat_monitoring domain' do
+      it 'returns the details URL' do
+        expect(presenter.details_url).to match(%r{#{project.web_url}/-/threat_monitoring/alerts/#{alert.iid}})
+      end
+    end
+  end
+end

spec/factories/alert_management/alerts.rb

@@ -95,6 +95,10 @@ FactoryBot.define do
       severity { 'unknown' }
     end
 
+    trait :threat_monitoring do
+      domain { :threat_monitoring }
+    end
+
     trait :prometheus do
       monitoring_tool { Gitlab::AlertManagement::Payload::MONITORING_TOOLS[:prometheus] }
       payload do