Refactor ordering of tests

* Split the sorting types into classes.
* Apply the same sorting to method sorting under the parallel
  test.

tool/test/testunit/test_sorting.rb

@@ -15,4 +15,61 @@ class TestTestUnitSorting < Test::Unit::TestCase
       f.read
     }
   end
+
+  Item = Struct.new(:name)
+  SEED = 0x50975eed
+
+  def make_test_list
+    (1..16).map {"test_%.3x" % rand(0x1000)}.freeze
+  end
+
+  def test_sort_alpha
+    sorter = Test::Unit::Order::Types[:alpha].new(SEED)
+    assert_kind_of(Test::Unit::Order::Types[:sorted], sorter)
+
+    list = make_test_list
+    sorted = list.sort
+    16.times do
+      assert_equal(sorted, sorter.sort_by_string(list))
+    end
+
+    list = list.map {|s| Item.new(s)}.freeze
+    sorted = list.sort_by(&:name)
+    16.times do
+      assert_equal(sorted, sorter.sort_by_name(list))
+    end
+  end
+
+  def test_sort_nosort
+    sorter = Test::Unit::Order::Types[:nosort].new(SEED)
+
+    list = make_test_list
+    16.times do
+      assert_equal(list, sorter.sort_by_string(list))
+    end
+
+    list = list.map {|s| Item.new(s)}.freeze
+    16.times do
+      assert_equal(list, sorter.sort_by_name(list))
+    end
+  end
+
+  def test_sort_random
+    type = Test::Unit::Order::Types[:random]
+    sorter = type.new(SEED)
+
+    list = make_test_list
+    sorted = type.new(SEED).sort_by_string(list).freeze
+    16.times do
+      assert_equal(sorted, sorter.sort_by_string(list))
+    end
+    assert_not_equal(sorted, type.new(SEED+1).sort_by_string(list))
+
+    list = list.map {|s| Item.new(s)}.freeze
+    sorted = sorted.map {|s| Item.new(s)}.freeze
+    16.times do
+      assert_equal(sorted, sorter.sort_by_name(list))
+    end
+    assert_not_equal(sorted, type.new(SEED+1).sort_by_name(list))
+  end
 end