Make merge trains in tests independent

If multiple tests use the same project they'll use the same merge
train. That can cause tests to fail if one tries to use the merge
train while it's in an unexpected state, e.g., trying to start a new
train when one is already running.

This creates a separate project for each test that uses a merge
train.

Uses the Commit API to add a file because it's faster than
pushing.

Adds a runners_token attribute to the Group resource, and lets
resources be reloaded so updated data can be fetched. It's not
clear why the runners token isn't available immediately upon
creating a group, but reloading the API data fixes it.

qa/qa/ee/page/merge_request/show.rb

@@ -284,12 +284,16 @@ module QA
             wait_for_animated_element :merge_immediately_button
 
             click_element :merge_immediately_button
+
+            finished_loading?
           end
 
           def merge_via_merge_train
             raise ElementNotFound, "Not ready to merge" unless ready_to_merge?
 
             click_element(:merge_button, text: "Start merge train")
+
+            finished_loading?
           end
 
           private

qa/qa/page/base.rb

@@ -177,7 +177,7 @@ module QA
         # The number of selectors should be able to be reduced after
         # migration to the new spinner is complete.
         # https://gitlab.com/groups/gitlab-org/-/epics/956
-        has_no_css?('.gl-spinner, .fa-spinner, .spinner', wait: Capybara.default_max_wait_time)
+        has_no_css?('.gl-spinner, .fa-spinner, .spinner', wait: QA::Support::Repeater::DEFAULT_MAX_WAIT_TIME)
       end
 
       def finished_loading_block?

qa/qa/page/merge_request/show.rb

@@ -155,6 +155,8 @@ module QA
         def merge!
           click_element :merge_button if ready_to_merge?
 
+          finished_loading?
+
           raise "Merge did not appear to be successful" unless merged?
         end
 

qa/qa/resource/api_fabricator.rb

@@ -31,6 +31,12 @@ module QA
         resource_web_url(api_post)
       end
 
+      def reload!
+        api_get
+
+        self
+      end
+
       def remove_via_api!
         api_delete
       end

qa/qa/resource/group.rb

@@ -16,6 +16,7 @@ module QA
 
       attribute :id
       attribute :name
+      attribute :runners_token
 
       def initialize
         @path = Runtime::Namespace.name

qa/qa/specs/features/ee/browser_ui/6_release/pipelines_for_merged_results_and_merge_trains_spec.rb

@@ -6,35 +6,44 @@ module QA
   context 'Release', :docker do
     describe 'Pipelines for merged results and merge trains' do
       before(:context) do
-        @project = Resource::Project.fabricate_via_api! do |project|
-          project.name = 'pipelines-for-merged-results-and-merge-trains'
-        end
-        @executor = "qa-runner-#{Time.now.to_i}"
+        @group = Resource::Group.fabricate_via_api!
 
         Resource::Runner.fabricate_via_api! do |runner|
-          runner.project = @project
-          runner.name = @executor
-          runner.tags = %w[qa test]
+          runner.token = @group.reload!.runners_token
+          runner.name = @group.name
+          runner.tags = [@group.name]
+        end
       end
 
-        Resource::Repository::ProjectPush.fabricate! do |project_push|
-          project_push.project = @project
-          project_push.file_name = '.gitlab-ci.yml'
-          project_push.commit_message = 'Add .gitlab-ci.yml'
-          project_push.file_content = <<~EOF
+      let(:project) do
+        Resource::Project.fabricate_via_api! do |project|
+          project.name = 'pipelines-for-merged-results-and-merge-trains'
+          project.group = @group
+        end
+      end
+
+      before do
+        Resource::Repository::Commit.fabricate_via_api! do |commit|
+          commit.project = project
+          commit.commit_message = 'Add .gitlab-ci.yml'
+          commit.add_files(
+            [
+              {
+                file_path: '.gitlab-ci.yml',
+                content:  <<~EOF
                   test:
-              tags: ["qa"]
+                    tags: [#{@group.name}]
                     script: echo 'OK'
                     only:
                     - merge_requests
                 EOF
-        end
+              }
+            ]
+          )
         end
 
-      before do
         Flow::Login.sign_in
-
-        @project.visit!
+        project.visit!
 
         Page::Project::Menu.perform(&:go_to_general_settings)
         Page::Project::Settings::Main.perform do |main|
@@ -46,7 +55,7 @@ module QA
       end
 
       after(:context) do
-        Service::DockerRun::GitlabRunner.new(@executor).remove!
+        Service::DockerRun::GitlabRunner.new(@group.name).remove!
       end
 
       it 'creates a pipeline with merged results' do
@@ -54,7 +63,7 @@ module QA
 
         # Create a branch that will be merged into master
         Resource::Repository::ProjectPush.fabricate! do |project_push|
-          project_push.project = @project
+          project_push.project = project
           project_push.new_branch = true
           project_push.branch_name = branch_name
           project_push.file_name = "file-#{SecureRandom.hex(8)}.txt"
@@ -62,7 +71,7 @@ module QA
 
         # Create a merge request to merge the branch we just created
         Resource::MergeRequest.fabricate_via_api! do |merge_request|
-          merge_request.project = @project
+          merge_request.project = project
           merge_request.source_branch = branch_name
           merge_request.no_preparation = true
         end.visit!
@@ -89,7 +98,7 @@ module QA
 
         # Create a branch that will be merged into master
         Resource::Repository::ProjectPush.fabricate! do |project_push|
-          project_push.project = @project
+          project_push.project = project
           project_push.new_branch = true
           project_push.branch_name = branch_name
           project_push.file_name = "file-#{SecureRandom.hex(8)}.txt"
@@ -98,7 +107,7 @@ module QA
 
         # Create a merge request to merge the branch we just created
         Resource::MergeRequest.fabricate_via_api! do |merge_request|
-          merge_request.project = @project
+          merge_request.project = project
           merge_request.source_branch = branch_name
           merge_request.no_preparation = true
         end.visit!