minitest: fix rails parallel test runner

lib/datadog/ci/contrib/minitest/patcher.rb

@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require_relative "runner"
 require_relative "reporter"
 require_relative "hooks"
 require_relative "runnable"
@@ -19,9 +20,14 @@ def target_version
           end
 
           def patch
-            ::Minitest::CompositeReporter.include(Reporter)
-            ::Minitest::Test.include(Hooks)
+            # test session start
+            ::Minitest.include(Runner)
+            # test suites (when not executed concurrently)
             ::Minitest::Runnable.include(Runnable)
+            # tests; test suites (when executed concurrently)
+            ::Minitest::Test.include(Hooks)
+            # test session finish
+            ::Minitest::CompositeReporter.include(Reporter)
           end
         end
       end

lib/datadog/ci/contrib/minitest/reporter.rb

@@ -37,21 +37,6 @@ def report(*)
               res
             end
 
-            def start(*)
-              return super unless datadog_configuration[:enabled]
-
-              test_session = CI.start_test_session(
-                tags: {
-                  CI::Ext::Test::TAG_FRAMEWORK => Ext::FRAMEWORK,
-                  CI::Ext::Test::TAG_FRAMEWORK_VERSION => CI::Contrib::Minitest::Integration.version.to_s
-                },
-                service: datadog_configuration[:service_name]
-              )
-              CI.start_test_module(test_session.name) if test_session
-
-              super
-            end
-
             private
 
             def datadog_configuration

lib/datadog/ci/contrib/minitest/runner.rb

@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require_relative "../../ext/test"
+require_relative "ext"
+
+module Datadog
+  module CI
+    module Contrib
+      module Minitest
+        module Runner
+          def self.included(base)
+            base.singleton_class.prepend(ClassMethods)
+          end
+
+          module ClassMethods
+            def init_plugins(*)
+              super
+
+              return unless datadog_configuration[:enabled]
+
+              test_session = CI.start_test_session(
+                tags: {
+                  CI::Ext::Test::TAG_FRAMEWORK => Ext::FRAMEWORK,
+                  CI::Ext::Test::TAG_FRAMEWORK_VERSION => CI::Contrib::Minitest::Integration.version.to_s
+                },
+                service: datadog_configuration[:service_name]
+              )
+              CI.start_test_module(test_session.name) if test_session
+            end
+
+            private
+
+            def datadog_configuration
+              Datadog.configuration.ci[:minitest]
+            end
+          end
+        end
+      end
+    end
+  end
+end

sig/datadog/ci/contrib/minitest/reporter.rbs

@@ -8,8 +8,6 @@ module Datadog
           class InstanceMethods < ::Minitest::AbstractReporter
             def report: (*untyped) -> untyped
 
-            def start: (*untyped) -> untyped
-
             private
 
             def datadog_configuration: () -> untyped

sig/datadog/ci/contrib/minitest/runner.rbs

@@ -0,0 +1,21 @@
+module Datadog
+  module CI
+    module Contrib
+      module Minitest
+        module Runner
+          def self.included: (untyped base) -> untyped
+
+          class ClassMethods
+            extend ::Minitest
+
+            def init_plugins: (*untyped) -> (nil | untyped)
+
+            private
+
+            def datadog_configuration: () -> untyped
+          end
+        end
+      end
+    end
+  end
+end