Add simplecov for code coverage

.github/workflows/ci.yml

@@ -25,5 +25,30 @@ jobs:
           bundler-cache: true # runs 'bundle install' and caches installed gems automatically
       - name: Run Tests
         env:
+          COVERAGE: true
           RUBYOPT: "-W:deprecated"
         run: bundle exec rake
+      - name: Rename coverage file by matrix run
+        run: mv coverage/coverage.xml coverage/coverage-ruby-${{ matrix.ruby }}.xml
+      - uses: actions/upload-artifact@v4
+        with:
+          name: coverage-ruby-${{ matrix.ruby }}
+          path: coverage
+          if-no-files-found: error
+
+  upload_coverage:
+    name: Upload Coverage
+    runs-on: ubuntu-latest
+    needs: [build]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/download-artifact@v4
+        with:
+          path: coverage
+          pattern: coverage-ruby-*
+          merge-multiple: true
+      - uses: codecov/codecov-action@v4
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          directory: coverage
+          fail_ci_if_error: true

Gemfile

@@ -2,3 +2,8 @@ source 'https://rubygems.org'
 
 # Specify your gem's dependencies in envied.gemspec
 gemspec
+
+group :test do
+  gem "simplecov", require: false
+  gem "simplecov-cobertura"
+end

Gemfile.lock

@@ -7,7 +7,9 @@ GEM
   remote: https://rubygems.org/
   specs:
     diff-lcs (1.5.1)
+    docile (1.4.0)
     rake (13.2.1)
+    rexml (3.2.6)
     rspec (3.13.0)
       rspec-core (~> 3.13.0)
       rspec-expectations (~> 3.13.0)
@@ -21,6 +23,15 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.13.0)
     rspec-support (3.13.1)
+    simplecov (0.22.0)
+      docile (~> 1.1)
+      simplecov-html (~> 0.11)
+      simplecov_json_formatter (~> 0.1)
+    simplecov-cobertura (2.1.0)
+      rexml
+      simplecov (~> 0.19)
+    simplecov-html (0.12.3)
+    simplecov_json_formatter (0.1.4)
 
 PLATFORMS
   ruby
@@ -30,6 +41,8 @@ DEPENDENCIES
   envied!
   rake (~> 13.0)
   rspec (~> 3.0)
+  simplecov
+  simplecov-cobertura
 
 BUNDLED WITH
    2.3.10

codecov.yml

@@ -0,0 +1,5 @@
+coverage:
+  status:
+    project:
+      default:
+        threshold: 0.05%

spec/spec_helper.rb

@@ -1,3 +1,12 @@
+if ENV.fetch("COVERAGE", false)
+  require "simplecov"
+  require "simplecov-cobertura"
+  SimpleCov.start do
+    add_filter %r{^/spec/}
+    formatter SimpleCov::Formatter::CoberturaFormatter
+  end
+end
+
 require "bundler/setup"
 require "envied"