Add flutter CI/CD template

Add Changelog entry

Rename job names

Include the default stages

Update template file

Added test files

Added missing to test

Update jobs in test file

Added code coverage report

Add export path

Update the change log file

Revert "Update jobs in test file"

This reverts commit 7298ce4f55df9755bf4909a49c8e8f4f0378b401.

changelogs/unreleased/add-flutter-cicd-template.yml

+---
+title: Add flutter CI/CD template
+merge_request: 46968
+author:
+type: added

lib/gitlab/ci/templates/Flutter.gitlab-ci.yml

+code_quality:
+  stage: test
+  image: "cirrusci/flutter:1.22.5"
+  before_script:
+    - pub global activate dart_code_metrics
+    - export PATH="$PATH":"$HOME/.pub-cache/bin"
+  script:
+    - metrics lib -r codeclimate  > gl-code-quality-report.json
+  artifacts:
+    reports:
+      codequality: gl-code-quality-report.json
+
+test:
+  stage: test
+  image: "cirrusci/flutter:1.22.5"
+  before_script:
+    - pub global activate junitreport
+    - export PATH="$PATH":"$HOME/.pub-cache/bin"
+  script:
+    - flutter test --machine --coverage | tojunit -o report.xml
+    - lcov --summary coverage/lcov.info
+    - genhtml coverage/lcov.info --output=coverage
+  coverage: '/lines\.*: \d+\.\d+\%/'
+  artifacts:
+    name: coverage
+    paths:
+      - $CI_PROJECT_DIR/coverage
+    reports:
+      junit: report.xml

spec/lib/gitlab/ci/templates/flutter_gitlab_ci_yaml_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'Flutter.gitlab-ci.yml' do
+  subject(:template) { Gitlab::Template::GitlabCiYmlTemplate.find('Flutter') }
+
+  describe 'the created pipeline' do
+    let_it_be(:user) { create(:admin) }
+
+    let(:pipeline_branch) { 'master' }
+    let(:project) { create(:project, :custom_repo, files: { 'README.md' => '' }) }
+    let(:service) { Ci::CreatePipelineService.new(project, user, ref: pipeline_branch ) }
+    let(:pipeline) { service.execute!(:push) }
+    let(:build_names) { pipeline.builds.pluck(:name) }
+
+    before do
+      stub_ci_pipeline_yaml_file(template.content)
+      allow(Ci::BuildScheduleWorker).to receive(:perform).and_return(true)
+    end
+
+    it 'creates test and code_quality jobs' do
+      expect(build_names).to include('test', 'code_quality')
+    end
+  end
+end