Check ruby test coverage before merging PRs

.github/workflows/ci.yml

@@ -61,3 +61,10 @@ jobs:
     uses: ./.github/workflows/pact-verify.yml
     with:
       ref: ${{ github.ref }}
+
+  test-coverage:
+    name: Check test coverage
+    needs:
+      - test-ruby
+      - pact-tests
+    uses: ./.github/workflows/test-coverage.yml

.github/workflows/minitest.yml

@@ -47,3 +47,10 @@ jobs:
           RAILS_ENV: test
           GOVUK_CONTENT_SCHEMAS_PATH: vendor/publishing-api/content_schemas
         run: bundle exec rake test
+
+      - name: Store test coverage percentage
+        uses: actions/upload-artifact@v4
+        with:
+          name: minitest-test-coverage
+          path: coverage/percentage.txt
+          retention-days: 1

.github/workflows/pact-verify.yml

@@ -64,3 +64,10 @@ jobs:
 
       - if: inputs.pact_artifact != ''
         run: bundle exec rake pact:verify:at[tmp/pacts/${{ inputs.pact_artifact_file_to_verify }}]
+
+      - name: Store test coverage percentage
+        uses: actions/upload-artifact@v4
+        with:
+          name: pact-test-coverage
+          path: coverage/percentage.txt
+          retention-days: 1

.github/workflows/test-coverage.yml

@@ -0,0 +1,20 @@
+name: Check test coverage
+
+on:
+  workflow_call:
+
+jobs:
+  check_ruby_test_coverage:
+    name: Check Ruby test coverage
+    runs-on: ubuntu-latest
+    steps:
+      - name: Retrieve minitest test coverage
+        uses: actions/download-artifact@v4
+        with:
+          name: minitest-test-coverage
+      - name: Retrieve pact test coverage
+        uses: actions/download-artifact@v4
+        with:
+          name: pact-test-coverage
+      - name: Check Ruby test coverage
+        run: ls -R

lib/tasks/test_coverage.rake

@@ -0,0 +1,8 @@
+desc "Start test coverage tool"
+task :test_coverage do
+  binding.pry
+  require_relative "../../test/test_coverage"
+end
+
+Rake::Task["pact:verify"].enhance %w[test_coverage]
+Rake::Task["pact:verify:at"].enhance %w[test_coverage]

test/test_coverage.rb

@@ -0,0 +1,12 @@
+unless defined?(TEST_COVERAGE_ACTIVATED)
+  TEST_COVERAGE_ACTIVATED = true
+  require "simplecov"
+  SimpleCov.at_exit do
+    SimpleCov.result.format!
+    File.write(
+      Rails.root.join("coverage/percentage.txt"),
+      SimpleCov.result.coverage_statistics[:line].percent.to_s,
+    )
+  end
+  SimpleCov.start "rails"
+end

test/test_helper.rb

@@ -1,6 +1,4 @@
-require "simplecov"
-SimpleCov.start "rails"
-
+require_relative "test_coverage"
 require "i18n/coverage"
 require "i18n/coverage/printers/file_printer"
 I18n::Coverage.config.printer = I18n::Coverage::Printers::FilePrinter