test/regression/test_format12.rb in write_xlsx-0.86.0 vs test/regression/test_format12.rb in write_xlsx-0.87.0

@@ -1,8 +1,8 @@
 # -*- coding: utf-8 -*-
 require 'helper'
 
-class TestRegressionFormat12 < Test::Unit::TestCase
+class TestRegressionFormat12 < Minitest::Test
   def setup
     setup_dir_var
   end
 
   def teardown