Add simplecov plugin for Minitest

Author: adam12

features/minitest_basic.feature

@@ -10,9 +10,26 @@ Feature:
     When I open the coverage report generated with `bundle exec rake minitest`
     Then I should see the groups:
       | name      | coverage | files |
-      | All Files | 80.0%    | 1     |
+      | All Files | 85.71%   | 3     |
 
     And I should see the source files:
       | name                                    | coverage |
       | lib/faked_project/some_class.rb         | 80.0 %   |
+      | minitest/some_test.rb                   | 100.0 %  |
+      | minitest/test_helper.rb                 | 75.0 %   |
+
+  Scenario:
+    Given SimpleCov for Minitest is configured with:
+      """
+      require 'simplecov'
+      SimpleCov.start
+      """
 
+    When I open the coverage report generated with `bundle exec ruby -Ilib:minitest minitest/other_test.rb`
+    Then I should see the groups:
+      | name      | coverage | files |
+      | All Files | 80.0%    | 1     |
+
+    And I should see the source files:
+      | name                                    | coverage |
+      | lib/faked_project/some_class.rb         | 80.0 %   |

lib/minitest/simplecov_plugin.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+module Minitest
+  def self.plugin_simplecov_init(_options)
+    Minitest.after_run do
+      SimpleCov.custom_at_exit if SimpleCov.respond_to?(:custom_at_exit)
+    end
+  end
+end

lib/simplecov/defaults.rb

@@ -21,22 +21,21 @@
 # Gotta stash this a-s-a-p, see the CommandGuesser class and i.e. #110 for further info
 SimpleCov::CommandGuesser.original_run_command = "#{$PROGRAM_NAME} #{ARGV.join(' ')}"
 
-if defined?(Minitest)
-  Minitest.after_run do
-    simplecov_at_exit
-  end
-else
-  at_exit do
-    simplecov_at_exit
+module SimpleCov
+  def self.custom_at_exit
+    # If we are in a different process than called start, don't interfere.
+    return if SimpleCov.pid != Process.pid
+
+    SimpleCov.set_exit_exception
+    SimpleCov.run_exit_tasks!
   end
 end
 
-def simplecov_at_exit
-  # If we are in a different process than called start, don't interfere.
-  return if SimpleCov.pid != Process.pid
+at_exit do
+  # Exit hook for Minitest defined in Minitest plugin
+  next if defined?(Minitest)
 
-  SimpleCov.set_exit_exception
-  SimpleCov.run_exit_tasks!
+  SimpleCov.custom_at_exit
 end
 
 # Autoload config from ~/.simplecov if present

spec/faked_project/minitest/other_test.rb

@@ -0,0 +1,24 @@
+require "bundler/setup"
+
+begin
+  require File.expand_path("simplecov_config", __dir__)
+rescue LoadError
+  warn "No SimpleCov config file found!"
+end
+
+require "minitest/autorun"
+require "faked_project/some_class"
+
+class OtherTest < Minitest::Test
+  def setup
+    @instance = SomeClass.new("foo")
+  end
+
+  def test_reverse
+    assert_equal "oof", @instance.reverse
+  end
+
+  def test_comparison
+    assert @instance.compare_with("foo")
+  end
+end