Don't show an "Unsubscribe" link in snippet comment notifications

app/models/sent_notification.rb

@@ -53,13 +53,17 @@ class SentNotification < ActiveRecord::Base
   end
 
   def unsubscribable?
-    !for_commit?
+    !(for_commit? || for_snippet?)
   end
 
   def for_commit?
     noteable_type == "Commit"
   end
 
+  def for_snippet?
+    noteable_type.end_with?('Snippet')
+  end
+
   def noteable
     if for_commit?
       project.commit(commit_id) rescue nil

changelogs/unreleased/23888-fix-unsubscription-link-for-snippet-notification.yml

+---
+title: Don't show an "Unsubscribe" link in snippet comment notifications
+merge_request: 14764
+author:
+type: fixed

spec/models/sent_notification_spec.rb

 require 'spec_helper'
 
 describe SentNotification do
+  set(:user) { create(:user) }
+  set(:project) { create(:project) }
+
   describe 'validation' do
     describe 'note validity' do
       context "when the project doesn't match the noteable's project" do
@@ -34,7 +37,6 @@ describe SentNotification do
   end
 
   describe '.record' do
-    let(:user) { create(:user) }
     let(:issue) { create(:issue) }
 
     it 'creates a new SentNotification' do
@@ -43,7 +45,6 @@ describe SentNotification do
   end
 
   describe '.record_note' do
-    let(:user) { create(:user) }
     let(:note) { create(:diff_note_on_merge_request) }
 
     it 'creates a new SentNotification' do
@@ -51,6 +52,123 @@ describe SentNotification do
     end
   end
 
+  describe '#unsubscribable?' do
+    shared_examples 'an unsubscribable notification' do |noteable_type|
+      subject { described_class.record(noteable, user.id) }
+
+      context "for #{noteable_type}" do
+        it { expect(subject).to be_unsubscribable }
+      end
+    end
+
+    shared_examples 'a non-unsubscribable notification' do |noteable_type|
+      subject { described_class.record(noteable, user.id) }
+
+      context "for a #{noteable_type}" do
+        it { expect(subject).not_to be_unsubscribable }
+      end
+    end
+
+    it_behaves_like 'an unsubscribable notification', 'issue' do
+      let(:noteable) { create(:issue, project: project) }
+    end
+
+    it_behaves_like 'an unsubscribable notification', 'merge request' do
+      let(:noteable) { create(:merge_request, source_project: project) }
+    end
+
+    it_behaves_like 'a non-unsubscribable notification', 'commit' do
+      let(:project) { create(:project, :repository) }
+      let(:noteable) { project.commit }
+    end
+
+    it_behaves_like 'a non-unsubscribable notification', 'personal snippet' do
+      let(:noteable) { create(:personal_snippet, project: project) }
+    end
+
+    it_behaves_like 'a non-unsubscribable notification', 'project snippet' do
+      let(:noteable) { create(:project_snippet, project: project) }
+    end
+  end
+
+  describe '#for_commit?' do
+    shared_examples 'a commit notification' do |noteable_type|
+      subject { described_class.record(noteable, user.id) }
+
+      context "for #{noteable_type}" do
+        it { expect(subject).to be_for_commit }
+      end
+    end
+
+    shared_examples 'a non-commit notification' do |noteable_type|
+      subject { described_class.record(noteable, user.id) }
+
+      context "for a #{noteable_type}" do
+        it { expect(subject).not_to be_for_commit }
+      end
+    end
+
+    it_behaves_like 'a non-commit notification', 'issue' do
+      let(:noteable) { create(:issue, project: project) }
+    end
+
+    it_behaves_like 'a non-commit notification', 'merge request' do
+      let(:noteable) { create(:merge_request, source_project: project) }
+    end
+
+    it_behaves_like 'a commit notification', 'commit' do
+      let(:project) { create(:project, :repository) }
+      let(:noteable) { project.commit }
+    end
+
+    it_behaves_like 'a non-commit notification', 'personal snippet' do
+      let(:noteable) { create(:personal_snippet, project: project) }
+    end
+
+    it_behaves_like 'a non-commit notification', 'project snippet' do
+      let(:noteable) { create(:project_snippet, project: project) }
+    end
+  end
+
+  describe '#for_snippet?' do
+    shared_examples 'a snippet notification' do |noteable_type|
+      subject { described_class.record(noteable, user.id) }
+
+      context "for #{noteable_type}" do
+        it { expect(subject).to be_for_snippet }
+      end
+    end
+
+    shared_examples 'a non-snippet notification' do |noteable_type|
+      subject { described_class.record(noteable, user.id) }
+
+      context "for a #{noteable_type}" do
+        it { expect(subject).not_to be_for_snippet }
+      end
+    end
+
+    it_behaves_like 'a non-snippet notification', 'issue' do
+      let(:noteable) { create(:issue, project: project) }
+    end
+
+    it_behaves_like 'a non-snippet notification', 'merge request' do
+      let(:noteable) { create(:merge_request, source_project: project) }
+    end
+
+    it_behaves_like 'a non-snippet notification', 'commit' do
+      let(:project) { create(:project, :repository) }
+      let(:noteable) { project.commit }
+    end
+
+    it_behaves_like 'a snippet notification', 'personal snippet' do
+      let(:noteable) { create(:personal_snippet, project: project) }
+    end
+
+    it_behaves_like 'a snippet notification', 'project snippet' do
+      let(:noteable) { create(:project_snippet, project: project) }
+    end
+  end
+
   describe '#create_reply' do
     context 'for issue' do
       let(:issue) { create(:issue) }