Drop Ruby 2.6 and JRuby 9.3; add JRuby 9.4, 10.0, and TruffleRuby

Author: sferik

.github/workflows/main.yml

@@ -10,7 +10,6 @@ jobs:
 
       matrix:
         ruby-version:
-          - '2.6'
           - '2.7'
           - '3.0'
           - '3.1'
@@ -19,8 +18,10 @@ jobs:
           - '3.4'
           - '4.0'
           - ruby-head
-          - jruby-9.3
+          - jruby-9.4
+          - jruby-10.0
           - jruby-head
+          - truffleruby
 
     steps:
       - uses: actions/checkout@v6
@@ -31,8 +32,8 @@ jobs:
         with:
           ruby-version: ${{ matrix.ruby-version }}
           bundler-cache: true
-        continue-on-error: ${{ (matrix.ruby-version == 'ruby-head') || (matrix.ruby-version == 'jruby-head') }}
+        continue-on-error: ${{ (matrix.ruby-version == 'ruby-head') || (matrix.ruby-version == 'jruby-head') || (matrix.ruby-version == 'truffleruby') }}
 
       - run: |
           bundle exec rake
-        continue-on-error: ${{ (matrix.ruby-version == 'ruby-head') || (matrix.ruby-version == 'jruby-head') }}
+        continue-on-error: ${{ (matrix.ruby-version == 'ruby-head') || (matrix.ruby-version == 'jruby-head') || (matrix.ruby-version == 'truffleruby') }}

.mutant.yml

@@ -0,0 +1,13 @@
+usage: opensource
+integration:
+  name: minitest
+includes:
+  - lib
+  - test
+requires:
+  - simplecov
+  - simplecov-html
+matcher:
+  subjects:
+    - SimpleCov::Formatter::HTMLFormatter#coverage_css_class
+    - SimpleCov::Formatter::HTMLFormatter#strength_css_class

test/test_mutation.rb

@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+require "helper"
+
+# Focused tests for mutation testing — exercises private methods directly.
+# Uses cover() to explicitly tell mutant which methods each test covers.
+class TestMutation < Minitest::Test
+  cover "SimpleCov::Formatter::HTMLFormatter#coverage_css_class" if respond_to?(:cover)
+
+  def test_coverage_css_class_green
+    assert_equal "green", formatter.send(:coverage_css_class, 100)
+    assert_equal "green", formatter.send(:coverage_css_class, 91)
+    assert_equal "green", formatter.send(:coverage_css_class, 90.01)
+  end
+
+  def test_coverage_css_class_yellow
+    assert_equal "yellow", formatter.send(:coverage_css_class, 90)
+    assert_equal "yellow", formatter.send(:coverage_css_class, 81)
+    assert_equal "yellow", formatter.send(:coverage_css_class, 80.01)
+  end
+
+  def test_coverage_css_class_red
+    assert_equal "red", formatter.send(:coverage_css_class, 80)
+    assert_equal "red", formatter.send(:coverage_css_class, 50)
+    assert_equal "red", formatter.send(:coverage_css_class, 0)
+  end
+
+  cover "SimpleCov::Formatter::HTMLFormatter#strength_css_class" if respond_to?(:cover)
+
+  def test_strength_css_class_green
+    assert_equal "green", formatter.send(:strength_css_class, 2)
+    assert_equal "green", formatter.send(:strength_css_class, 1.01)
+  end
+
+  def test_strength_css_class_yellow
+    assert_equal "yellow", formatter.send(:strength_css_class, 1)
+    assert_equal "yellow", formatter.send(:strength_css_class, 1.0)
+  end
+
+  def test_strength_css_class_red
+    assert_equal "red", formatter.send(:strength_css_class, 0.99)
+    assert_equal "red", formatter.send(:strength_css_class, 0)
+  end
+
+private
+
+  def formatter
+    @formatter ||= SimpleCov::Formatter::HTMLFormatter.new
+  end
+end