Handles unsubscribe from notifications via email

- allows unsubscription processing of email in format "reply+%{key}+unsubscribe@acme.com" (example)
- if config.address includes %{key} and replies are enabled every unsubscriable message will include mailto: link in its List-Unsubscribe header

5 files changed, 106 insertions, 3 deletions

diff --git a/spec/lib/gitlab/email/email_shared_blocks.rb b/spec/lib/gitlab/email/email_shared_blocks.rb
index 19298e261e3..9d806fc524d 100644
--- a/spec/lib/gitlab/email/email_shared_blocks.rb
+++ b/spec/lib/gitlab/email/email_shared_blocks.rb
@@ -18,7 +18,7 @@ shared_context :email_shared_context do
   end
 end
 
-shared_examples :email_shared_examples do
+shared_examples :reply_processing_shared_examples do
   context "when the user could not be found" do
     before do
       user.destroy
diff --git a/spec/lib/gitlab/email/handler/create_issue_handler_spec.rb b/spec/lib/gitlab/email/handler/create_issue_handler_spec.rb
index cb3651e3845..08897a4c310 100644
--- a/spec/lib/gitlab/email/handler/create_issue_handler_spec.rb
+++ b/spec/lib/gitlab/email/handler/create_issue_handler_spec.rb
@@ -3,7 +3,7 @@ require_relative '../email_shared_blocks'
 
 describe Gitlab::Email::Handler::CreateIssueHandler, lib: true do
   include_context :email_shared_context
-  it_behaves_like :email_shared_examples
+  it_behaves_like :reply_processing_shared_examples
 
   before do
     stub_incoming_email_setting(enabled: true, address: "incoming+%{key}@appmail.adventuretime.ooo")
diff --git a/spec/lib/gitlab/email/handler/create_note_handler_spec.rb b/spec/lib/gitlab/email/handler/create_note_handler_spec.rb
index 48660d1dd1b..cebbeff50cf 100644
--- a/spec/lib/gitlab/email/handler/create_note_handler_spec.rb
+++ b/spec/lib/gitlab/email/handler/create_note_handler_spec.rb
@@ -3,7 +3,7 @@ require_relative '../email_shared_blocks'
 
 describe Gitlab::Email::Handler::CreateNoteHandler, lib: true do
   include_context :email_shared_context
-  it_behaves_like :email_shared_examples
+  it_behaves_like :reply_processing_shared_examples
 
   before do
     stub_incoming_email_setting(enabled: true, address: "reply+%{key}@appmail.adventuretime.ooo")
diff --git a/spec/lib/gitlab/email/handler/unsubscribe_handler_spec.rb b/spec/lib/gitlab/email/handler/unsubscribe_handler_spec.rb
new file mode 100644
index 00000000000..a444257754b
--- /dev/null
+++ b/spec/lib/gitlab/email/handler/unsubscribe_handler_spec.rb
@@ -0,0 +1,61 @@
+require 'spec_helper'
+require_relative '../email_shared_blocks'
+
+describe Gitlab::Email::Handler::UnsubscribeHandler, lib: true do
+  include_context :email_shared_context
+
+  before do
+    stub_incoming_email_setting(enabled: true, address: 'reply+%{key}@appmail.adventuretime.ooo')
+    stub_config_setting(host: 'localhost')
+  end
+
+  let(:email_raw) { fixture_file('emails/valid_reply.eml').gsub(mail_key, "#{mail_key}+unsubscribe") }
+  let(:project) { create(:project, :public) }
+  let(:user) { create(:user) }
+  let(:noteable) { create(:issue, project: project) }
+
+  let!(:sent_notification) { SentNotification.record(noteable, user.id, mail_key) }
+
+  context 'when notification concerns a commit' do
+    let(:commit) { create(:commit, project: project) }
+    let!(:sent_notification) { SentNotification.record(commit, user.id, mail_key) }
+
+    it 'handler does not raise an error' do
+      expect { receiver.execute }.not_to raise_error
+    end
+  end
+
+  context 'user is unsubscribed' do
+    it 'leaves user unsubscribed' do
+      expect { receiver.execute }.not_to change { noteable.subscribed?(user) }.from(false)
+    end
+  end
+
+  context 'user is subscribed' do
+    before do
+      noteable.subscribe(user)
+    end
+
+    it 'unsubscribes user from notable' do
+      expect { receiver.execute }.to change { noteable.subscribed?(user) }.from(true).to(false)
+    end
+  end
+
+  context 'when the noteable could not be found' do
+    before do
+      noteable.destroy
+    end
+
+    it 'raises a NoteableNotFoundError' do
+      expect { receiver.execute }.to raise_error(Gitlab::Email::NoteableNotFoundError)
+    end
+  end
+
+  context 'when no sent notification for the mail key could be found' do
+    let(:email_raw) { fixture_file('emails/wrong_mail_key.eml') }
+
+    it 'raises a SentNotificationNotFoundError' do
+      expect { receiver.execute }.to raise_error(Gitlab::Email::SentNotificationNotFoundError)
+    end
+  end
+end
diff --git a/spec/lib/gitlab/incoming_email_spec.rb b/spec/lib/gitlab/incoming_email_spec.rb
index 1dcf2c0668b..7e951e3fcdd 100644
--- a/spec/lib/gitlab/incoming_email_spec.rb
+++ b/spec/lib/gitlab/incoming_email_spec.rb
@@ -23,6 +23,48 @@ describe Gitlab::IncomingEmail, lib: true do
     end
   end
 
+  describe 'self.supports_wildcard?' do
+    context 'address contains the wildard placeholder' do
+      before do
+        stub_incoming_email_setting(address: 'replies+%{key}@example.com')
+      end
+
+      it 'confirms that wildcard is supported' do
+        expect(described_class.supports_wildcard?).to be_truthy
+      end
+    end
+
+    context "address doesn't contain the wildcard placeholder" do
+      before do
+        stub_incoming_email_setting(address: 'replies@example.com')
+      end
+
+      it 'returns that wildcard is not supported' do
+        expect(described_class.supports_wildcard?).to be_falsey
+      end
+    end
+
+    context 'address is not set' do
+      before do
+        stub_incoming_email_setting(address: nil)
+      end
+
+      it 'returns that wildard is not supported' do
+        expect(described_class.supports_wildcard?).to be_falsey
+      end
+    end
+  end
+
+  context 'self.unsubscribe_address' do
+    before do
+      stub_incoming_email_setting(address: 'replies+%{key}@example.com')
+    end
+
+    it 'returns the address with interpolated reply key and unsubscribe suffix' do
+      expect(described_class.unsubscribe_address('key')).to eq('replies+key+unsubscribe@example.com')
+    end
+  end
+
   context "self.reply_address" do
     before do
       stub_incoming_email_setting(address: "replies+%{key}@example.com")