Don't override ActiveSupport::TestCase.test_order

Seemingly some test suites depend on this

Updated tests to verify the change to the parallelization flag instead

Author: ricardotk002

railties/test/application/test_runner_test.rb

@@ -547,25 +547,25 @@ def test_parallel_is_disabled_when_single_file_is_run
 
         class ParallelTest < ActiveSupport::TestCase
           def test_verify_test_order
-            puts "Test order: \#{self.class.test_order}"
+            puts "Test parallelization disabled: \#{ActiveSupport.test_parallelization_disabled}"
           end
         end
       RUBY
 
       output = run_test_command(file_name)
 
-      assert_match "Test order: random", output
+      assert_match "Test parallelization disabled: true", output
     end
 
-    def test_random_order_is_enabled_when_multiple_files_are_run
+    def test_parallel_is_enabled_when_multiple_files_are_run
       exercise_parallelization_regardless_of_machine_core_count(with: :processes, force: false)
 
       file_1 = app_file "test/unit/parallel_test_first.rb", <<-RUBY
         require "test_helper"
 
         class ParallelTestFirst < ActiveSupport::TestCase
           def test_verify_test_order
-            puts "Test order (file 1): \#{self.class.test_order}"
+            puts "Test parallelization disabled (file 1): \#{ActiveSupport.test_parallelization_disabled}"
           end
         end
       RUBY
@@ -575,18 +575,18 @@ def test_verify_test_order
 
         class ParallelTestSecond < ActiveSupport::TestCase
           def test_verify_test_order
-            puts "Test order (file 2): \#{self.class.test_order}"
+            puts "Test parallelization disabled (file 2): \#{ActiveSupport.test_parallelization_disabled}"
           end
         end
       RUBY
 
       output = run_test_command([file_1, file_2].join(" "))
 
-      assert_match "Test order (file 1): random", output
-      assert_match "Test order (file 2): random", output
+      assert_match "Test parallelization disabled (file 1): false", output
+      assert_match "Test parallelization disabled (file 2): false", output
     end
 
-    def test_random_order_is_enabled_when_PARALLEL_WORKERS_is_set
+    def test_parallel_is_enabled_when_PARALLEL_WORKERS_is_set
       @old = ENV["PARALLEL_WORKERS"]
       ENV["PARALLEL_WORKERS"] = "5"
 
@@ -597,14 +597,14 @@ def test_random_order_is_enabled_when_PARALLEL_WORKERS_is_set
 
         class ParallelTest < ActiveSupport::TestCase
           def test_verify_test_order
-            puts "Test order: \#{self.class.test_order}"
+            puts "Test parallelization disabled: \#{ActiveSupport.test_parallelization_disabled}"
           end
         end
       RUBY
 
       output = run_test_command(file_name)
 
-      assert_match "Test order: random", output
+      assert_match "Test parallelization disabled: false", output
     ensure
       ENV["PARALLEL_WORKERS"] = @old
     end