Move minitest plugin

Minitest Rails plugin should be loaded on test_help, so we report errors
even when not running from the runner.

Also fix the backtrace

3 files changed, 20 insertions, 21 deletions

diff --git a/railties/lib/rails/test_help.rb b/railties/lib/rails/test_help.rb
index 8953e5fd48..d52bb46728 100644
--- a/railties/lib/rails/test_help.rb
+++ b/railties/lib/rails/test_help.rb
@@ -2,6 +2,7 @@
 # so fixtures aren't loaded into that environment
 abort("Abort testing: Your Rails environment is running in production mode!") if Rails.env.production?
 
+require "rails/test_unit/minitest_plugin"
 require 'active_support/testing/autorun'
 require 'active_support/test_case'
 require 'action_controller'
@@ -9,12 +10,6 @@ require 'action_controller/test_case'
 require 'action_dispatch/testing/integration'
 require 'rails/generators/test_case'
 
-# Config Rails backtrace in tests.
-require 'rails/backtrace_cleaner'
-if ENV["BACKTRACE"].nil?
-  Minitest.backtrace_filter = Rails.backtrace_cleaner
-end
-
 if defined?(ActiveRecord::Base)
   ActiveRecord::Migration.maintain_test_schema!
 
diff --git a/railties/lib/rails/test_unit/minitest_plugin.rb b/railties/lib/rails/test_unit/minitest_plugin.rb
new file mode 100644
index 0000000000..149aad372c
--- /dev/null
+++ b/railties/lib/rails/test_unit/minitest_plugin.rb
@@ -0,0 +1,15 @@
+require "minitest"
+require "rails/test_unit/reporter"
+
+def Minitest.plugin_rails_init(options)
+  self.reporter << Rails::TestUnitReporter.new(options[:io], options)
+  if $rails_test_runner && (method = $rails_test_runner.find_method)
+    options[:filter] = method
+  end
+
+  if ENV["BACKTRACE"].nil? && !($rails_test_runner && $rails_test_runner.show_backtrace?)
+    Minitest.backtrace_filter = Rails.backtrace_cleaner
+  end
+end
+Minitest.extensions << 'rails'
+
diff --git a/railties/lib/rails/test_unit/runner.rb b/railties/lib/rails/test_unit/runner.rb
index 31ce94a503..c777091b57 100644
--- a/railties/lib/rails/test_unit/runner.rb
+++ b/railties/lib/rails/test_unit/runner.rb
@@ -2,7 +2,6 @@ require "ostruct"
 require "optparse"
 require "rake/file_list"
 require "method_source"
-require "rails/test_unit/reporter"
 
 module Rails
   class TestRunner
@@ -58,17 +57,7 @@ module Rails
     end
 
     def run
-      enable_backtrace if @options[:backtrace]
-
       $rails_test_runner = self
-      def Minitest.plugin_rails_init(options)
-        self.reporter << Rails::TestUnitReporter.new(options[:io], options)
-        if method = $rails_test_runner.find_method
-          options[:filter] = method
-        end
-      end
-      Minitest.extensions << 'rails'
-
       run_tests
     end
 
@@ -82,6 +71,10 @@ module Rails
       method[1] if method
     end
 
+    def show_backtrace?
+      @options[:backtrace]
+    end
+
     private
     def run_tests
       test_files.to_a.each do |file|
@@ -102,10 +95,6 @@ module Rails
       Rake::FileList[pattern]
     end
 
-    def enable_backtrace
-      ENV["BACKTRACE"] = "1"
-    end
-
     def test_methods
       methods_map = []
       suites = Minitest::Runnable.runnables.shuffle