Implement the implied CI/CD config for AutoDevOps

Behind an application setting, which defaults to false, this commit
implements the implied CI/CD config. Which means that in the case we
can't find the `.gitlab-ci.yml` on the commit we want to start a
pipeline for, we fall back to an implied configuration.

For now the Bash template has been copied to
`Auto-Devops.gitlab-ci.yml` so the tests actually work.

Fixes #34777

3 files changed, 52 insertions, 5 deletions

diff --git a/spec/models/application_setting_spec.rb b/spec/models/application_setting_spec.rb
index 359753b600e..95ebd016064 100644
--- a/spec/models/application_setting_spec.rb
+++ b/spec/models/application_setting_spec.rb
@@ -5,6 +5,7 @@ describe ApplicationSetting do
 
   it { expect(setting).to be_valid }
   it { expect(setting.uuid).to be_present }
+  it { expect(setting).to have_db_column(:auto_devops_enabled) }
 
   describe 'validations' do
     let(:http)  { 'http://example.com' }
diff --git a/spec/models/ci/pipeline_spec.rb b/spec/models/ci/pipeline_spec.rb
index b84e3ff18e8..a7e0da04f55 100644
--- a/spec/models/ci/pipeline_spec.rb
+++ b/spec/models/ci/pipeline_spec.rb
@@ -784,13 +784,47 @@ describe Ci::Pipeline, :mailer do
   end
 
   describe '#ci_yaml_file' do
-    it 'reports error if the file is not found' do
-      allow(pipeline.project).to receive(:ci_config_path) { 'custom' }
+    let(:implied_yml) { Gitlab::Template::GitlabCiYmlTemplate.find('Auto-DevOps').content }
 
-      pipeline.ci_yaml_file
+    context 'when AutoDevops is enabled' do
+      it 'returns the configuration if found' do
+        allow(pipeline.project.repository).to receive(:gitlab_ci_yml_for)
+          .and_return('config')
 
-      expect(pipeline.yaml_errors)
-        .to eq('Failed to load CI/CD config file at custom')
+        expect(pipeline.ci_yaml_file).to be_a(String)
+        expect(pipeline.ci_yaml_file).not_to eq(implied_yml)
+        expect(pipeline.yaml_errors).to be_nil
+      end
+
+      it 'returns the implied configuration when its not found' do
+        allow_any_instance_of(ApplicationSetting)
+          .to receive(:auto_devops_enabled?) { true }
+        allow(pipeline.project).to receive(:ci_config_path) { 'custom' }
+
+        expect(pipeline.ci_yaml_file).to eq(implied_yml)
+      end
+    end
+
+    context 'when AudoDevOps is disabled' do
+      context 'when an invalid path is given' do
+        it 'sets the yaml errors' do
+          allow(pipeline.project).to receive(:ci_config_path) { 'custom' }
+
+          expect(pipeline.ci_yaml_file).to be_nil
+          expect(pipeline.yaml_errors)
+            .to start_with('Failed to load CI/CD config file')
+        end
+      end
+
+      context 'when the config file can be found' do
+        it 'has no yaml_errors' do
+          allow(pipeline.project.repository).to receive(:gitlab_ci_yml_for)
+            .and_return('config')
+
+          expect(pipeline.ci_yaml_file).to eq('config')
+          expect(pipeline.yaml_errors).to be_nil
+        end
+      end
     end
   end
 
diff --git a/spec/models/project_auto_devops_spec.rb b/spec/models/project_auto_devops_spec.rb
new file mode 100644
index 00000000000..d534dacf079
--- /dev/null
+++ b/spec/models/project_auto_devops_spec.rb
@@ -0,0 +1,12 @@
+require 'spec_helper'
+
+describe ProjectAutoDevops, type: :model do
+  subject { build_stubbed(:project_auto_devops) }
+
+  it { is_expected.to belong_to(:project) }
+
+  it { is_expected.to respond_to(:created_at) }
+  it { is_expected.to respond_to(:updated_at) }
+
+  it { is_expected.to be_enabled }
+end