add model configuration spec to check for new models. Also refactored attribute_configuration spec

spec/lib/gitlab/import_export/all_models.json

+{
+  "issues": [
+    "subscriptions",
+    "award_emoji",
+    "author",
+    "assignee",
+    "updated_by",
+    "milestone",
+    "notes",
+    "label_links",
+    "labels",
+    "todos",
+    "user_agent_detail",
+    "project",
+    "moved_to",
+    "events"
+  ],
+  "events": [
+    "author",
+    "project",
+    "target"
+  ],
+  "notes": [
+    "award_emoji",
+    "project",
+    "noteable",
+    "author",
+    "updated_by",
+    "resolved_by",
+    "todos",
+    "events"
+  ],
+  "label_links": [
+    "target",
+    "label"
+  ],
+  "label": [
+    "subscriptions",
+    "project",
+    "lists",
+    "label_links",
+    "issues",
+    "merge_requests"
+  ],
+  "milestone": [
+    "project",
+    "issues",
+    "labels",
+    "merge_requests",
+    "participants",
+    "events"
+  ],
+  "snippets": [
+    "author",
+    "project",
+    "notes"
+  ],
+  "releases": [
+    "project"
+  ],
+  "project_members": [
+    "created_by",
+    "user",
+    "source",
+    "project"
+  ],
+  "merge_requests": [
+    "subscriptions",
+    "award_emoji",
+    "author",
+    "assignee",
+    "updated_by",
+    "milestone",
+    "notes",
+    "label_links",
+    "labels",
+    "todos",
+    "target_project",
+    "source_project",
+    "merge_user",
+    "merge_request_diffs",
+    "merge_request_diff",
+    "events"
+  ],
+  "merge_request_diff": [
+    "merge_request"
+  ],
+  "pipelines": [
+    "project",
+    "user",
+    "statuses",
+    "builds",
+    "trigger_requests"
+  ],
+  "statuses": [
+    "project",
+    "pipeline",
+    "user"
+  ],
+  "variables": [
+    "project"
+  ],
+  "triggers": [
+    "project",
+    "trigger_requests"
+  ],
+  "deploy_keys": [
+    "user",
+    "deploy_keys_projects",
+    "projects"
+  ],
+  "services": [
+    "project",
+    "service_hook"
+  ],
+  "hooks": [
+    "project"
+  ],
+  "protected_branches": [
+    "project",
+    "merge_access_levels",
+    "push_access_levels"
+  ],
+  "project": [
+    "taggings",
+    "base_tags",
+    "tag_taggings",
+    "tags",
+    "creator",
+    "group",
+    "namespace",
+    "board",
+    "last_event",
+    "services",
+    "campfire_service",
+    "drone_ci_service",
+    "emails_on_push_service",
+    "builds_email_service",
+    "irker_service",
+    "pivotaltracker_service",
+    "hipchat_service",
+    "flowdock_service",
+    "assembla_service",
+    "asana_service",
+    "gemnasium_service",
+    "slack_service",
+    "buildkite_service",
+    "bamboo_service",
+    "teamcity_service",
+    "pushover_service",
+    "jira_service",
+    "redmine_service",
+    "custom_issue_tracker_service",
+    "bugzilla_service",
+    "gitlab_issue_tracker_service",
+    "external_wiki_service",
+    "forked_project_link",
+    "forked_from_project",
+    "forked_project_links",
+    "forks",
+    "merge_requests",
+    "fork_merge_requests",
+    "issues",
+    "labels",
+    "events",
+    "milestones",
+    "notes",
+    "snippets",
+    "hooks",
+    "protected_branches",
+    "project_members",
+    "users",
+    "requesters",
+    "deploy_keys_projects",
+    "deploy_keys",
+    "users_star_projects",
+    "starrers",
+    "releases",
+    "lfs_objects_projects",
+    "lfs_objects",
+    "project_group_links",
+    "invited_groups",
+    "todos",
+    "notification_settings",
+    "import_data",
+    "commit_statuses",
+    "pipelines",
+    "builds",
+    "runner_projects",
+    "runners",
+    "variables",
+    "triggers",
+    "environments",
+    "deployments"
+  ]
+}
\ No newline at end of file

spec/lib/gitlab/import_export/attribute_configuration_spec.rb

@@ -7,6 +7,8 @@ require 'spec_helper'
 # Likewise, new models added to import_export.yml, will need to be added with their correspondent attributes
 # to this spec.
 describe 'Attribute configuration', lib: true do
+  include ConfigurationHelper
+
   let(:config_hash) { YAML.load_file(Gitlab::ImportExport.config_file).deep_stringify_keys }
   let(:relation_names) do
     names = names_from_tree(config_hash['project_tree'])
@@ -58,20 +60,6 @@ describe 'Attribute configuration', lib: true do
     end
   end
 
-  # Returns a list of models from hashes/arrays contained in +project_tree+
-  def names_from_tree(project_tree)
-    project_tree.map do |branch_or_model|
-      branch_or_model =  branch_or_model.to_s if branch_or_model.is_a?(Symbol)
-
-      branch_or_model.is_a?(String) ? branch_or_model : names_from_tree(branch_or_model)
-    end
-  end
-
-  def relation_class_for_name(relation_name)
-    relation_name = Gitlab::ImportExport::RelationFactory::OVERRIDES[relation_name.to_sym] || relation_name
-    relation_name.to_s.classify.constantize
-  end
-
   def failure_message(relation_class, new_attributes)
     <<-MSG
       It looks like #{relation_class}, which is exported using the project Import/Export, has new attributes: #{new_attributes.join(',')}

spec/lib/gitlab/import_export/model_configuration_spec.rb

+require 'spec_helper'
+
+# Finds if a new model has been added that can potentially be part of the Import/Export
+# If it finds a new model, it will show a +failure_message+ with the options available.
+describe 'Model configuration', lib: true do
+  include ConfigurationHelper
+
+  let(:config_hash) { YAML.load_file(Gitlab::ImportExport.config_file).deep_stringify_keys }
+  let(:relation_names) do
+    names = names_from_tree(config_hash['project_tree'])
+
+    # Remove duplicated or add missing models
+    # - project is not part of the tree, so it has to be added manually.
+    # - milestone, labels have both singular and plural versions in the tree, so remove the duplicates.
+    # - User, Author... Models we don not care about for checking relations
+    names.flatten.uniq - ['milestones', 'labels', 'user', 'author'] + ['project']
+  end
+
+  let(:all_models_json) { 'spec/lib/gitlab/import_export/all_models.json' }
+  let(:all_models) { JSON.parse(File.read(all_models_json)) }
+  let(:current_models) { setup_models }
+
+  it 'has no new models' do
+    relation_names.each do |relation_name|
+      new_models = current_models[relation_name] - all_models[relation_name]
+      expect(new_models).to be_empty, failure_message(relation_name.classify, new_models)
+    end
+  end
+
+  # List of current relations between models, in the format of
+  # {model: [model_2, model3], ...}
+  def setup_models
+    all_models_hash = {}
+
+    relation_names.each do |relation_name|
+      relation_class = relation_class_for_name(relation_name)
+
+      all_models_hash[relation_name] = relation_class.reflect_on_all_associations.map do |association|
+        association.name.to_s
+      end
+    end
+
+    all_models_hash
+  end
+
+  def failure_message(relation_name, new_models)
+    <<-MSG
+      New model(s) <#{new_models.join(',')}> have been added, related to #{relation_name}, which is exported by
+      the Import/Export feature.
+
+      If you don't think this should be exported, please add it to MODELS_JSON, inside the #{relation_name} hash.
+      If you think we should export this new model, please add it to IMPORT_EXPORT_CONFIG.
+
+      MODELS_JSON: #{File.expand_path(all_models_json)}
+      IMPORT_EXPORT_CONFIG: #{Gitlab::ImportExport.config_file}
+    MSG
+  end
+end

spec/support/import_export/configuration_helper.rb

+module ConfigurationHelper
+  # Returns a list of models from hashes/arrays contained in +project_tree+
+  def names_from_tree(project_tree)
+    project_tree.map do |branch_or_model|
+      branch_or_model =  branch_or_model.to_s if branch_or_model.is_a?(Symbol)
+
+      branch_or_model.is_a?(String) ? branch_or_model : names_from_tree(branch_or_model)
+    end
+  end
+
+  def relation_class_for_name(relation_name)
+    relation_name = Gitlab::ImportExport::RelationFactory::OVERRIDES[relation_name.to_sym] || relation_name
+    relation_name.to_s.classify.constantize
+  end
+end