Add CI config for mail-smtp_pool

This job runs the specs in the vendored gem's directory

.gitlab-ci.yml

@@ -100,6 +100,7 @@ include:
   - local: .gitlab/ci/qa.gitlab-ci.yml
   - local: .gitlab/ci/reports.gitlab-ci.yml
   - local: .gitlab/ci/rails.gitlab-ci.yml
+  - local: .gitlab/ci/vendored-gems.gitlab-ci.yml
   - local: .gitlab/ci/review.gitlab-ci.yml
   - local: .gitlab/ci/rules.gitlab-ci.yml
   - local: .gitlab/ci/setup.gitlab-ci.yml

.gitlab/ci/rules.gitlab-ci.yml

@@ -925,6 +925,16 @@
     - <<: *if-merge-request
       changes: [".gitlab/ci/rails.gitlab-ci.yml"]
 
+#######################
+# Vendored gems rules #
+#######################
+
+.vendor:rules:mail-smtp_pool:
+  rules:
+    - <<: *if-merge-request
+      changes: ["vendor/gems/mail-smtp_pool/**/*"]
+    - <<: *if-merge-request-title-run-all-rspec
+
 ##################
 # Releases rules #
 ##################

.gitlab/ci/vendored-gems.gitlab-ci.yml

+vendor mail-smtp_pool:
+  extends:
+    - .vendor:rules:mail-smtp_pool
+  needs: []
+  trigger:
+    include: vendor/gems/mail-smtp_pool/.gitlab-ci.yml
+    strategy: depend

vendor/gems/mail-smtp_pool/.gitlab-ci.yml

-.test-template: &test
+workflow:
+  rules:
+    - if: $CI_MERGE_REQUEST_ID
+
+.rspec:
   cache:
+    key: mail-smtp_pool-ruby
     paths:
-      - vendor/ruby
+      - vendor/gems/mail-smtp_pool/vendor/ruby
   before_script:
+    - cd vendor/gems/mail-smtp_pool
     - ruby -v                                   # Print out ruby version for debugging
     - gem install bundler --no-document         # Bundler is not installed with the image
-    - bundle install -j $(nproc) --path vendor  # Install dependencies into ./vendor/ruby
+    - bundle config set --local path 'vendor'   # Install dependencies into ./vendor/ruby
+    - bundle install -j $(nproc)
   script:
-    - bundle exec rspec spec
+    - bundle exec rspec
 
 rspec-2.6:
   image: "ruby:2.6"
-  <<: *test
+  extends: .rspec
 
 rspec-2.7:
   image: "ruby:2.7"
-  <<: *test
+  extends: .rspec
 
 rspec-3.0:
   image: "ruby:3.0"
-  <<: *test
+  extends: .rspec