Merge branch 'zj-slash-commands-mattermost' into 'master'

Slash command for mattermost

Closes  #22540

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)


See merge request !7438

26 files changed, 756 insertions, 29 deletions

diff --git a/app/controllers/projects/services_controller.rb b/app/controllers/projects/services_controller.rb
index 40a23a6f806..30c2a5d9982 100644
--- a/app/controllers/projects/services_controller.rb
+++ b/app/controllers/projects/services_controller.rb
@@ -28,6 +28,8 @@ class Projects::ServicesController < Projects::ApplicationController
   end
 
   def test
+    return render_404 unless @service.can_test?
+
     data = @service.test_data(project, current_user)
     outcome = @service.test(data)
 
diff --git a/app/helpers/triggers_helper.rb b/app/helpers/triggers_helper.rb
index c41181bab3d..b0135ea2e95 100644
--- a/app/helpers/triggers_helper.rb
+++ b/app/helpers/triggers_helper.rb
@@ -6,4 +6,8 @@ module TriggersHelper
       "#{Settings.gitlab.url}/api/v3/projects/#{project_id}/ref/#{ref}/trigger/builds"
     end
   end
+
+  def service_trigger_url(service)
+    "#{Settings.gitlab.url}/api/v3/projects/#{service.project_id}/services/#{service.to_param}/trigger"
+  end
 end
diff --git a/app/models/project.rb b/app/models/project.rb
index f9bcc547c36..34b44f90f1c 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -23,7 +23,9 @@ class Project < ActiveRecord::Base
 
   cache_markdown_field :description, pipeline: :description
 
-  delegate :feature_available?, :builds_enabled?, :wiki_enabled?, :merge_requests_enabled?, to: :project_feature, allow_nil: true
+  delegate :feature_available?, :builds_enabled?, :wiki_enabled?,
+           :merge_requests_enabled?, :issues_enabled?, to: :project_feature,
+                                                       allow_nil: true
 
   default_value_for :archived, false
   default_value_for :visibility_level, gitlab_config_features.visibility_level
@@ -75,6 +77,7 @@ class Project < ActiveRecord::Base
 
   has_one :last_event, -> {order 'events.created_at DESC'}, class_name: 'Event'
   has_many :boards, before_add: :validate_board_limit, dependent: :destroy
+  has_many :chat_services
 
   # Project services
   has_one :campfire_service, dependent: :destroy
@@ -89,6 +92,7 @@ class Project < ActiveRecord::Base
   has_one :assembla_service, dependent: :destroy
   has_one :asana_service, dependent: :destroy
   has_one :gemnasium_service, dependent: :destroy
+  has_one :mattermost_slash_commands_service, dependent: :destroy
   has_one :slack_service, dependent: :destroy
   has_one :buildkite_service, dependent: :destroy
   has_one :bamboo_service, dependent: :destroy
diff --git a/app/models/project_feature.rb b/app/models/project_feature.rb
index 5c53c8f1ee5..03194fc2141 100644
--- a/app/models/project_feature.rb
+++ b/app/models/project_feature.rb
@@ -60,6 +60,10 @@ class ProjectFeature < ActiveRecord::Base
     merge_requests_access_level > DISABLED
   end
 
+  def issues_enabled?
+    issues_access_level > DISABLED
+  end
+
   private
 
   # Validates builds and merge requests access level
diff --git a/app/models/project_services/chat_service.rb b/app/models/project_services/chat_service.rb
new file mode 100644
index 00000000000..d36beff5fa6
--- /dev/null
+++ b/app/models/project_services/chat_service.rb
@@ -0,0 +1,21 @@
+# Base class for Chat services
+# This class is not meant to be used directly, but only to inherrit from.
+class ChatService < Service
+  default_value_for :category, 'chat'
+
+  has_many :chat_names, foreign_key: :service_id
+
+  def valid_token?(token)
+    self.respond_to?(:token) &&
+      self.token.present? &&
+      ActiveSupport::SecurityUtils.variable_size_secure_compare(token, self.token)
+  end
+
+  def supported_events
+    []
+  end
+
+  def trigger(params)
+    raise NotImplementedError
+  end
+end
diff --git a/app/models/project_services/mattermost_slash_commands_service.rb b/app/models/project_services/mattermost_slash_commands_service.rb
new file mode 100644
index 00000000000..67902329593
--- /dev/null
+++ b/app/models/project_services/mattermost_slash_commands_service.rb
@@ -0,0 +1,56 @@
+class MattermostSlashCommandsService < ChatService
+  include TriggersHelper
+
+  prop_accessor :token
+
+  def can_test?
+    false
+  end
+
+  def title
+    'Mattermost Command'
+  end
+
+  def description
+    "Perform common operations on GitLab in Mattermost"
+  end
+
+  def to_param
+    'mattermost_slash_commands'
+  end
+
+  def help
+    "This service allows you to use slash commands with your Mattermost installation.<br/>
+    To setup this Service you need to create a new <b>Slash commands</b> in your Mattermost integration panel.<br/>
+    <br/>
+    Create integration with URL #{service_trigger_url(self)} and enter the token below."
+  end
+
+  def fields
+    [
+      { type: 'text', name: 'token', placeholder: '' }
+    ]
+  end
+
+  def trigger(params)
+    return nil unless valid_token?(params[:token])
+
+    user = find_chat_user(params)
+    unless user
+      url = authorize_chat_name_url(params)
+      return Mattermost::Presenter.authorize_chat_name(url)
+    end
+
+    Gitlab::ChatCommands::Command.new(project, user, params).execute
+  end
+
+  private
+
+  def find_chat_user(params)
+    ChatNames::FindUserService.new(self, params).execute
+  end
+
+  def authorize_chat_name_url(params)
+    ChatNames::AuthorizeUserService.new(self, params).execute
+  end
+end
diff --git a/app/models/service.rb b/app/models/service.rb
index 9d6ff190cdf..edd6b5329f3 100644
--- a/app/models/service.rb
+++ b/app/models/service.rb
@@ -202,7 +202,6 @@ class Service < ActiveRecord::Base
       bamboo
       buildkite
       builds_email
-      pipelines_email
       bugzilla
       campfire
       custom_issue_tracker
@@ -214,6 +213,8 @@ class Service < ActiveRecord::Base
       hipchat
       irker
       jira
+      mattermost_slash_commands
+      pipelines_email
       pivotaltracker
       pushover
       redmine
diff --git a/app/views/shared/_service_settings.html.haml b/app/views/shared/_service_settings.html.haml
index 5254d265918..601ef51737a 100644
--- a/app/views/shared/_service_settings.html.haml
+++ b/app/views/shared/_service_settings.html.haml
@@ -10,26 +10,27 @@
   .col-sm-10
     = form.check_box :active
 
-.form-group
-  = form.label :url, "Trigger", class: 'control-label'
-
-  .col-sm-10
-    - @service.supported_events.each do |event|
-      %div
-        = form.check_box service_event_field_name(event), class: 'pull-left'
-        .prepend-left-20
-          = form.label service_event_field_name(event), class: 'list-label' do
-            %strong
-              = event.humanize
-
-      - field = @service.event_field(event)
-
-      - if field
-        %p
-          = form.text_field field[:name], class: "form-control", placeholder: field[:placeholder]
-
-      %p.light
-        = service_event_description(event)
+- if @service.supported_events.present?
+  .form-group
+    = form.label :url, "Trigger", class: 'control-label'
+
+    .col-sm-10
+      - @service.supported_events.each do |event|
+        %div
+          = form.check_box service_event_field_name(event), class: 'pull-left'
+          .prepend-left-20
+            = form.label service_event_field_name(event), class: 'list-label' do
+              %strong
+                = event.humanize
+
+        - field = @service.event_field(event)
+
+        - if field
+          %p
+            = form.text_field field[:name], class: "form-control", placeholder: field[:placeholder]
+
+        %p.light
+          = service_event_description(event)
 
 - @service.global_fields.each do |field|
   - type = field[:type]
diff --git a/changelogs/unreleased/zj-slash-commands-mattermost.yml b/changelogs/unreleased/zj-slash-commands-mattermost.yml
new file mode 100644
index 00000000000..996ffe954f3
--- /dev/null
+++ b/changelogs/unreleased/zj-slash-commands-mattermost.yml
@@ -0,0 +1,4 @@
+---
+title: Added Mattermost slash command
+merge_request: 7438
+author: 
diff --git a/lib/api/helpers.rb b/lib/api/helpers.rb
index 84cc9200d1b..2c593dbb4ea 100644
--- a/lib/api/helpers.rb
+++ b/lib/api/helpers.rb
@@ -85,8 +85,8 @@ module API
       end
     end
 
-    def project_service
-      @project_service ||= user_project.find_or_initialize_service(params[:service_slug].underscore)
+    def project_service(project = user_project)
+      @project_service ||= project.find_or_initialize_service(params[:service_slug].underscore)
       @project_service || not_found!("Service")
     end
 
diff --git a/lib/api/services.rb b/lib/api/services.rb
index fc8598daa32..4d23499aa39 100644
--- a/lib/api/services.rb
+++ b/lib/api/services.rb
@@ -1,10 +1,10 @@
 module API
   # Projects API
   class Services < Grape::API
-    before { authenticate! }
-    before { authorize_admin_project }
-
     resource :projects do
+      before { authenticate! }
+      before { authorize_admin_project }
+
       # Set <service_slug> service for project
       #
       # Example Request:
@@ -59,5 +59,28 @@ module API
         present project_service, with: Entities::ProjectService, include_passwords: current_user.is_admin?
       end
     end
+
+    resource :projects do
+      desc 'Trigger a slash command' do
+        detail 'Added in GitLab 8.13'
+      end
+      post ':id/services/:service_slug/trigger' do
+        project = Project.find_with_namespace(params[:id]) || Project.find_by(id: params[:id])
+
+        # This is not accurate, but done to prevent leakage of the project names
+        not_found!('Service') unless project
+
+        service = project_service(project)
+
+        result = service.try(:active?) && service.try(:trigger, params)
+
+        if result
+          status result[:status] || 200
+          present result
+        else
+          not_found!('Service')
+        end
+      end
+    end
   end
 end
diff --git a/lib/gitlab/chat_commands/base_command.rb b/lib/gitlab/chat_commands/base_command.rb
new file mode 100644
index 00000000000..e59d69b72b9
--- /dev/null
+++ b/lib/gitlab/chat_commands/base_command.rb
@@ -0,0 +1,49 @@
+module Gitlab
+  module ChatCommands
+    class BaseCommand
+      QUERY_LIMIT = 5
+
+      def self.match(_text)
+        raise NotImplementedError
+      end
+
+      def self.help_message
+        raise NotImplementedError
+      end
+
+      def self.available?(_project)
+        raise NotImplementedError
+      end
+
+      def self.allowed?(_user, _ability)
+        true
+      end
+
+      def self.can?(object, action, subject)
+        Ability.allowed?(object, action, subject)
+      end
+
+      def execute(_)
+        raise NotImplementedError
+      end
+
+      def collection
+        raise NotImplementedError
+      end
+
+      attr_accessor :project, :current_user, :params
+
+      def initialize(project, user, params = {})
+        @project, @current_user, @params = project, user, params.dup
+      end
+
+      private
+
+      def find_by_iid(iid)
+        resource = collection.find_by(iid: iid)
+
+        readable?(resource) ? resource : nil
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/chat_commands/command.rb b/lib/gitlab/chat_commands/command.rb
new file mode 100644
index 00000000000..5f131703d40
--- /dev/null
+++ b/lib/gitlab/chat_commands/command.rb
@@ -0,0 +1,61 @@
+module Gitlab
+  module ChatCommands
+    class Command < BaseCommand
+      COMMANDS = [
+        Gitlab::ChatCommands::IssueShow,
+        Gitlab::ChatCommands::IssueCreate,
+      ].freeze
+
+      def execute
+        command, match = match_command
+
+        if command
+          if command.allowed?(project, current_user)
+            present command.new(project, current_user, params).execute(match)
+          else
+            access_denied
+          end
+        else
+          help(help_messages)
+        end
+      end
+
+      private
+
+      def match_command
+        match = nil
+        service = available_commands.find do |klass|
+          match = klass.match(command)
+        end
+
+        [service, match]
+      end
+
+      def help_messages
+        available_commands.map(&:help_message)
+      end
+
+      def available_commands
+        COMMANDS.select do |klass|
+          klass.available?(project)
+        end
+      end
+
+      def command
+        params[:text]
+      end
+
+      def help(messages)
+        Mattermost::Presenter.help(messages, params[:command])
+      end
+
+      def access_denied
+        Mattermost::Presenter.access_denied
+      end
+
+      def present(resource)
+        Mattermost::Presenter.present(resource)
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/chat_commands/issue_command.rb b/lib/gitlab/chat_commands/issue_command.rb
new file mode 100644
index 00000000000..f1bc36239d5
--- /dev/null
+++ b/lib/gitlab/chat_commands/issue_command.rb
@@ -0,0 +1,17 @@
+module Gitlab
+  module ChatCommands
+    class IssueCommand < BaseCommand
+      def self.available?(project)
+        project.issues_enabled? && project.default_issues_tracker?
+      end
+
+      def collection
+        project.issues
+      end
+
+      def readable?(issue)
+        self.class.can?(current_user, :read_issue, issue)
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/chat_commands/issue_create.rb b/lib/gitlab/chat_commands/issue_create.rb
new file mode 100644
index 00000000000..98338ebfa27
--- /dev/null
+++ b/lib/gitlab/chat_commands/issue_create.rb
@@ -0,0 +1,24 @@
+module Gitlab
+  module ChatCommands
+    class IssueCreate < IssueCommand
+      def self.match(text)
+        /\Aissue\s+create\s+(?<title>[^\n]*)\n*(?<description>.*)\z/.match(text)
+      end
+
+      def self.help_message
+        'issue create <title>\n<description>'
+      end
+
+      def self.allowed?(project, user)
+        can?(user, :create_issue, project)
+      end
+
+      def execute(match)
+        title = match[:title]
+        description = match[:description]
+
+        Issues::CreateService.new(project, current_user, title: title, description: description).execute
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/chat_commands/issue_show.rb b/lib/gitlab/chat_commands/issue_show.rb
new file mode 100644
index 00000000000..f5bceb038e5
--- /dev/null
+++ b/lib/gitlab/chat_commands/issue_show.rb
@@ -0,0 +1,17 @@
+module Gitlab
+  module ChatCommands
+    class IssueShow < IssueCommand
+      def self.match(text)
+        /\Aissue\s+show\s+(?<iid>\d+)/.match(text)
+      end
+
+      def self.help_message
+        "issue show <id>"
+      end
+
+      def execute(match)
+        find_by_iid(match[:iid])
+      end
+    end
+  end
+end
diff --git a/lib/mattermost/presenter.rb b/lib/mattermost/presenter.rb
new file mode 100644
index 00000000000..bfbb089eb02
--- /dev/null
+++ b/lib/mattermost/presenter.rb
@@ -0,0 +1,117 @@
+module Mattermost
+  class Presenter
+    class << self
+      include Gitlab::Routing.url_helpers
+
+      def authorize_chat_name(url)
+        message = if url
+                    ":wave: Hi there! Before I do anything for you, please [connect your GitLab account](#{url})."
+                  else
+                    ":sweat_smile: Couldn't identify you, nor can I autorize you!"
+                  end
+
+        ephemeral_response(message)
+      end
+
+      def help(commands, trigger)
+        if commands.none?
+          ephemeral_response("No commands configured")
+        else
+          commands.map! { |command| "#{trigger} #{command}" }
+          message = header_with_list("Available commands", commands)
+
+          ephemeral_response(message)
+        end
+      end
+
+      def present(resource)
+        return not_found unless resource
+
+        if resource.respond_to?(:count)
+          if resource.count > 1
+            return multiple_resources(resource)
+          elsif resource.count == 0
+            return not_found
+          else
+            resource = resource.first
+          end
+        end
+
+        single_resource(resource)
+      end
+
+      def access_denied
+        ephemeral_response("Whoops! That action is not allowed. This incident will be [reported](https://xkcd.com/838/).")
+      end
+
+      private
+
+      def not_found
+        ephemeral_response("404 not found! GitLab couldn't find what you were looking for! :boom:")
+      end
+
+      def single_resource(resource)
+        return error(resource) if resource.errors.any? || !resource.persisted?
+
+        message = "### #{title(resource)}"
+        message << "\n\n#{resource.description}" if resource.description
+
+        in_channel_response(message)
+      end
+
+      def multiple_resources(resources)
+        resources.map! { |resource| title(resource) }
+
+        message = header_with_list("Multiple results were found:", resources)
+
+        ephemeral_response(message)
+      end
+
+      def error(resource)
+        message = header_with_list("The action was not successful, because:", resource.errors.messages)
+
+        ephemeral_response(message)
+      end
+
+      def title(resource)
+        "[#{resource.to_reference} #{resource.title}](#{url(resource)})"
+      end
+
+      def header_with_list(header, items)
+        message = [header]
+
+        items.each do |item|
+          message << "- #{item}"
+        end
+
+        message.join("\n")
+      end
+
+      def url(resource)
+        url_for(
+          [
+            resource.project.namespace.becomes(Namespace),
+            resource.project,
+            resource
+          ]
+        )
+      end
+
+      def ephemeral_response(message)
+        {
+          response_type: :ephemeral,
+          text: message,
+          status: 200
+        }
+      end
+
+      def in_channel_response(message)
+        {
+          response_type: :in_channel,
+          text: message,
+          status: 200
+        }
+      end
+    end
+  end
+end
diff --git a/spec/lib/gitlab/chat_commands/command_spec.rb b/spec/lib/gitlab/chat_commands/command_spec.rb
new file mode 100644
index 00000000000..8cedbb0240f
--- /dev/null
+++ b/spec/lib/gitlab/chat_commands/command_spec.rb
@@ -0,0 +1,55 @@
+require 'spec_helper'
+
+describe Gitlab::ChatCommands::Command, service: true do
+  let(:project) { create(:empty_project) }
+  let(:user) { create(:user) }
+
+  subject { described_class.new(project, user, params).execute }
+
+  describe '#execute' do
+    context 'when no command is available' do
+      let(:params) { { text: 'issue show 1' } }
+      let(:project) { create(:project, has_external_issue_tracker: true) }
+
+      it 'displays 404 messages' do
+        expect(subject[:response_type]).to be(:ephemeral)
+        expect(subject[:text]).to start_with('404 not found')
+      end
+    end
+
+    context 'when an unknown command is triggered' do
+      let(:params) { { command: '/gitlab', text: "unknown command 123" } }
+
+      it 'displays the help message' do
+        expect(subject[:response_type]).to be(:ephemeral)
+        expect(subject[:text]).to start_with('Available commands')
+        expect(subject[:text]).to match('/gitlab issue show')
+      end
+    end
+
+    context 'the user can not create an issue' do
+      let(:params) { { text: "issue create my new issue" } }
+
+      it 'rejects the actions' do
+        expect(subject[:response_type]).to be(:ephemeral)
+        expect(subject[:text]).to start_with('Whoops! That action is not allowed')
+      end
+    end
+
+    context 'issue is successfully created' do
+      let(:params) { { text: "issue create my new issue" } }
+
+      before do
+        project.team << [user, :master]
+      end
+
+      it 'presents the issue' do
+        expect(subject[:text]).to match("my new issue")
+      end
+
+      it 'shows a link to the new issue' do
+        expect(subject[:text]).to match(/\/issues\/\d+/)
+      end
+    end
+  end
+end
diff --git a/spec/lib/gitlab/chat_commands/issue_create_spec.rb b/spec/lib/gitlab/chat_commands/issue_create_spec.rb
new file mode 100644
index 00000000000..df0c317ccea
--- /dev/null
+++ b/spec/lib/gitlab/chat_commands/issue_create_spec.rb
@@ -0,0 +1,52 @@
+require 'spec_helper'
+
+describe Gitlab::ChatCommands::IssueCreate, service: true do
+  describe '#execute' do
+    let(:project) { create(:empty_project) }
+    let(:user) { create(:user) }
+    let(:regex_match) { described_class.match("issue create bird is the word") }
+
+    before do
+      project.team << [user, :master]
+    end
+
+    subject do
+      described_class.new(project, user).execute(regex_match)
+    end
+
+    context 'without description' do
+      it 'creates the issue' do
+        expect { subject }.to change { project.issues.count }.by(1)
+
+        expect(subject.title).to eq('bird is the word')
+      end
+    end
+
+    context 'with description' do
+      let(:description) { "Surfin bird" }
+      let(:regex_match) { described_class.match("issue create bird is the word\n#{description}") }
+
+      it 'creates the issue with description' do
+        subject
+
+        expect(Issue.last.description).to eq(description)
+      end
+    end
+  end
+
+  describe '.match' do
+    it 'matches the title without description' do
+      match = described_class.match("issue create my title")
+
+      expect(match[:title]).to eq('my title')
+      expect(match[:description]).to eq("")
+    end
+
+    it 'matches the title with description' do
+      match = described_class.match("issue create my title\n\ndescription")
+
+      expect(match[:title]).to eq('my title')
+      expect(match[:description]).to eq('description')
+    end
+  end
+end
diff --git a/spec/lib/gitlab/chat_commands/issue_show_spec.rb b/spec/lib/gitlab/chat_commands/issue_show_spec.rb
new file mode 100644
index 00000000000..331a4604e9b
--- /dev/null
+++ b/spec/lib/gitlab/chat_commands/issue_show_spec.rb
@@ -0,0 +1,40 @@
+require 'spec_helper'
+
+describe Gitlab::ChatCommands::IssueShow, service: true do
+  describe '#execute' do
+    let(:issue) { create(:issue) }
+    let(:project) { issue.project }
+    let(:user) { issue.author }
+    let(:regex_match) { described_class.match("issue show #{issue.iid}") }
+
+    before do
+      project.team << [user, :master]
+    end
+
+    subject do
+      described_class.new(project, user).execute(regex_match)
+    end
+
+    context 'the issue exists' do
+      it 'returns the issue' do
+        expect(subject.iid).to be issue.iid
+      end
+    end
+
+    context 'the issue does not exist' do
+      let(:regex_match) { described_class.match("issue show 2343242") }
+
+      it "returns nil" do
+        expect(subject).to be_nil
+      end
+    end
+  end
+
+  describe 'self.match' do
+    it 'matches the iid' do
+      match = described_class.match("issue show 123")
+
+      expect(match[:iid]).to eq("123")
+    end
+  end
+end
diff --git a/spec/lib/gitlab/import_export/all_models.yml b/spec/lib/gitlab/import_export/all_models.yml
index 02b11bd999a..fe3c39e38db 100644
--- a/spec/lib/gitlab/import_export/all_models.yml
+++ b/spec/lib/gitlab/import_export/all_models.yml
@@ -116,6 +116,7 @@ project:
 - base_tags
 - tag_taggings
 - tags
+- chat_services
 - creator
 - group
 - namespace
@@ -127,6 +128,7 @@ project:
 - emails_on_push_service
 - builds_email_service
 - pipelines_email_service
+- mattermost_slash_commands_service
 - irker_service
 - pivotaltracker_service
 - hipchat_service
@@ -188,4 +190,4 @@ award_emoji:
 - awardable
 - user
 priorities:
-- label
\ No newline at end of file
+- label
diff --git a/spec/models/project_services/chat_service_spec.rb b/spec/models/project_services/chat_service_spec.rb
new file mode 100644
index 00000000000..c6a45a3e1be
--- /dev/null
+++ b/spec/models/project_services/chat_service_spec.rb
@@ -0,0 +1,15 @@
+require 'spec_helper'
+
+describe ChatService, models: true do
+  describe "Associations" do
+    it { is_expected.to have_many :chat_names }
+  end
+
+  describe '#valid_token?' do
+    subject { described_class.new }
+
+    it 'is false as it has no token' do
+      expect(subject.valid_token?('wer')).to be_falsey
+    end
+  end
+end
diff --git a/spec/models/project_services/mattermost_slash_commands_service_spec.rb b/spec/models/project_services/mattermost_slash_commands_service_spec.rb
new file mode 100644
index 00000000000..4a1037e950b
--- /dev/null
+++ b/spec/models/project_services/mattermost_slash_commands_service_spec.rb
@@ -0,0 +1,99 @@
+require 'spec_helper'
+
+describe MattermostSlashCommandsService, models: true do
+  describe "Associations" do
+    it { is_expected.to respond_to :token }
+  end
+
+  describe '#valid_token?' do
+    subject { described_class.new }
+
+    context 'when the token is empty' do
+      it 'is false' do
+        expect(subject.valid_token?('wer')).to be_falsey
+      end
+    end
+
+    context 'when there is a token' do
+      before do
+        subject.token = '123'
+      end
+
+      it 'accepts equal tokens' do
+        expect(subject.valid_token?('123')).to be_truthy
+      end
+    end
+  end
+
+  describe '#trigger' do
+    subject { described_class.new }
+
+    context 'no token is passed' do
+      let(:params) { Hash.new }
+
+      it 'returns nil' do
+        expect(subject.trigger(params)).to be_nil
+      end
+    end
+
+    context 'with a token passed' do
+      let(:project) { create(:empty_project) }
+      let(:params) { { token: 'token' } }
+
+      before do
+        allow(subject).to receive(:token).and_return('token')
+      end
+
+      context 'no user can be found' do
+        context 'when no url can be generated' do
+          it 'responds with the authorize url' do
+            response = subject.trigger(params)
+
+            expect(response[:response_type]).to eq :ephemeral
+            expect(response[:text]).to start_with ":sweat_smile: Couldn't identify you"
+          end
+        end
+
+        context 'when an auth url can be generated' do
+          let(:params) do
+            {
+              team_domain: 'http://domain.tld',
+              team_id: 'T3423423',
+              user_id: 'U234234',
+              user_name: 'mepmep',
+              token: 'token'
+            }
+          end
+
+          let(:service) do
+            project.create_mattermost_slash_commands_service(
+              properties: { token: 'token' }
+            )
+          end
+
+          it 'generates the url' do
+            response = service.trigger(params)
+
+            expect(response[:text]).to start_with(':wave: Hi there!')
+          end
+        end
+      end
+
+      context 'when the user is authenticated' do
+        let!(:chat_name) { create(:chat_name, service: service) }
+        let(:service) do
+          project.create_mattermost_slash_commands_service(
+            properties: { token: 'token' }
+          )
+        end
+        let(:params) { { token: 'token', team_id: chat_name.team_id, user_id: chat_name.chat_id } }
+
+        it 'triggers the command' do
+          expect_any_instance_of(Gitlab::ChatCommands::Command).to receive(:execute)
+
+          service.trigger(params)
+        end
+      end
+    end
+  end
+end
diff --git a/spec/models/project_spec.rb b/spec/models/project_spec.rb
index 42aa617cb1e..33b5d8388c8 100644
--- a/spec/models/project_spec.rb
+++ b/spec/models/project_spec.rb
@@ -20,6 +20,7 @@ describe Project, models: true do
     it { is_expected.to have_many(:deploy_keys) }
     it { is_expected.to have_many(:hooks).dependent(:destroy) }
     it { is_expected.to have_many(:protected_branches).dependent(:destroy) }
+    it { is_expected.to have_many(:chat_services) }
     it { is_expected.to have_one(:forked_project_link).dependent(:destroy) }
     it { is_expected.to have_one(:slack_service).dependent(:destroy) }
     it { is_expected.to have_one(:pushover_service).dependent(:destroy) }
@@ -35,6 +36,7 @@ describe Project, models: true do
     it { is_expected.to have_one(:hipchat_service).dependent(:destroy) }
     it { is_expected.to have_one(:flowdock_service).dependent(:destroy) }
     it { is_expected.to have_one(:assembla_service).dependent(:destroy) }
+    it { is_expected.to have_one(:mattermost_slash_commands_service).dependent(:destroy) }
     it { is_expected.to have_one(:gemnasium_service).dependent(:destroy) }
     it { is_expected.to have_one(:buildkite_service).dependent(:destroy) }
     it { is_expected.to have_one(:bamboo_service).dependent(:destroy) }
diff --git a/spec/requests/api/services_spec.rb b/spec/requests/api/services_spec.rb
index 2aadab3cbe1..ce9c96ace21 100644
--- a/spec/requests/api/services_spec.rb
+++ b/spec/requests/api/services_spec.rb
@@ -88,4 +88,61 @@ describe API::API, api: true  do
       end
     end
   end
+
+  describe 'POST /projects/:id/services/:slug/trigger' do
+    let!(:project) { create(:empty_project) }
+    let(:service_name) { 'mattermost_slash_commands' }
+
+    context 'no service is available' do
+      it 'returns a not found message' do
+        post api("/projects/#{project.id}/services/idonotexist/trigger")
+
+        expect(response).to have_http_status(404)
+        expect(json_response["message"]).to eq("404 Service Not Found")
+      end
+    end
+
+    context 'the service exists' do
+      let(:params) { { token: 'token' } }
+
+      context 'the service is not active' do
+        let!(:inactive_service) do
+          project.create_mattermost_slash_commands_service(
+            active: false,
+            properties: { token: 'token' }
+          )
+        end
+
+        it 'when the service is inactive' do
+          post api("/projects/#{project.id}/services/mattermost_slash_commands/trigger")
+
+          expect(response).to have_http_status(404)
+        end
+      end
+
+      context 'the service is active' do
+        let!(:active_service) do
+          project.create_mattermost_slash_commands_service(
+            active: true,
+            properties: { token: 'token' }
+          )
+        end
+
+        it 'retusn status 200' do
+          post api("/projects/#{project.id}/services/mattermost_slash_commands/trigger"), params
+
+          expect(response).to have_http_status(200)
+        end
+      end
+
+      context 'when the project can not be found' do
+        it 'returns a generic 404' do
+          post api("/projects/404/services/mattermost_slash_commands/trigger"), params
+
+          expect(response).to have_http_status(404)
+          expect(json_response["message"]).to eq("404 Service Not Found")
+        end
+      end
+    end
+  end
 end
diff --git a/spec/services/chat_names/find_user_service_spec.rb b/spec/services/chat_names/find_user_service_spec.rb
index 5b885b2c657..51441e8f3be 100644
--- a/spec/services/chat_names/find_user_service_spec.rb
+++ b/spec/services/chat_names/find_user_service_spec.rb
@@ -13,7 +13,7 @@ describe ChatNames::FindUserService, services: true do
       context 'when existing user is requested' do
         let(:params) { { team_id: chat_name.team_id, user_id: chat_name.chat_id } }
 
-        it 'returns existing user' do
+        it 'returns the existing user' do
           is_expected.to eq(user)
         end