diff --git a/tool/lib/core_assertions.rb b/tool/lib/core_assertions.rb
index fd3c187191..36ff2a08ba 100644
--- a/tool/lib/core_assertions.rb
+++ b/tool/lib/core_assertions.rb
@@ -271,7 +271,7 @@ module Test
         capture_stdout = true
         unless /mswin|mingw/ =~ RUBY_PLATFORM
           capture_stdout = false
-          opt[:out] = MiniTest::Unit.output if defined?(MiniTest::Unit)
+          opt[:out] = Test::Unit::Runner.output if defined?(Test::Unit::Runner)
           res_p, res_c = IO.pipe
           opt[:ios] = [res_c]
         end
diff --git a/tool/lib/leakchecker.rb b/tool/lib/leakchecker.rb
index 1d45a3a8df..052bea5e53 100644
--- a/tool/lib/leakchecker.rb
+++ b/tool/lib/leakchecker.rb
@@ -112,7 +112,7 @@ class LeakChecker
       }
       unless fd_leaked.empty?
         unless @@try_lsof == false
-          @@try_lsof |= system(*%W[lsof -a -d #{fd_leaked.minmax.uniq.join("-")} -p #$$], out: MiniTest::Unit.output)
+          @@try_lsof |= system(*%W[lsof -a -d #{fd_leaked.minmax.uniq.join("-")} -p #$$], out: Test::Unit::Runner.output)
         end
       end
       h.each {|fd, list|
@@ -286,7 +286,7 @@ class LeakChecker
   end
 
   def puts(*a)
-    output = MiniTest::Unit.output
+    output = Test::Unit::Runner.output
     if defined?(output.set_encoding)
       output.set_encoding(nil, nil)
     end
diff --git a/tool/lib/test/unit.rb b/tool/lib/test/unit.rb
index 356911150d..6b9f385a3a 100644
--- a/tool/lib/test/unit.rb
+++ b/tool/lib/test/unit.rb
@@ -83,7 +83,7 @@ module Test
       private
       def setup_options(opts, options)
         opts.separator 'minitest options:'
-        opts.version = MiniTest::Unit::VERSION
+        opts.version = Test::Unit::Runner::VERSION
 
         opts.on '-h', '--help', 'Display this help.' do
           puts opts
@@ -1196,14 +1196,14 @@ module Test
       # A simple hook allowing you to run a block of code after _all_ of
       # the tests are done. Eg:
       #
-      #   MiniTest::Unit.after_tests { p $debugging_info }
+      #   Test::Unit::Runner.after_tests { p $debugging_info }
 
       def self.after_tests &block
         @@after_tests << block
       end
 
       ##
-      # Registers MiniTest::Unit to run tests at process exit
+      # Registers Test::Unit::Runner to run tests at process exit
 
       def self.autorun
         at_exit {
@@ -1221,7 +1221,7 @@ module Test
             exit false if exit_code && exit_code != 0
           }
 
-          exit_code = MiniTest::Unit.new.run ARGV
+          exit_code = Test::Unit::Runner.new.run ARGV
         } unless @@installed_at_exit
         @@installed_at_exit = true
       end
@@ -1234,7 +1234,7 @@ module Test
       end
 
       ##
-      # Sets MiniTest::Unit to write output to +stream+.  $stdout is the default
+      # Sets Test::Unit::Runner to write output to +stream+.  $stdout is the default
       # output
 
       def self.output= stream
@@ -1242,16 +1242,16 @@ module Test
       end
 
       ##
-      # Tells MiniTest::Unit to delegate to +runner+, an instance of a
-      # MiniTest::Unit subclass, when MiniTest::Unit#run is called.
+      # Tells Test::Unit::Runner to delegate to +runner+, an instance of a
+      # Test::Unit::Runner subclass, when Test::Unit::Runner#run is called.
 
       def self.runner= runner
         @@runner = runner
       end
 
       ##
-      # Returns the MiniTest::Unit subclass instance that will be used
-      # to run the tests. A MiniTest::Unit instance is the default
+      # Returns the Test::Unit::Runner subclass instance that will be used
+      # to run the tests. A Test::Unit::Runner instance is the default
       # runner.
 
       def self.runner
@@ -1403,13 +1403,13 @@ module Test
       # Record the result of a single test. Makes it very easy to gather
       # information. Eg:
       #
-      #   class StatisticsRecorder < MiniTest::Unit
+      #   class StatisticsRecorder < Test::Unit::Runner
       #     def record suite, method, assertions, time, error
       #       # ... record the results somewhere ...
       #     end
       #   end
       #
-      #   MiniTest::Unit.runner = StatisticsRecorder.new
+      #   Test::Unit::Runner.runner = StatisticsRecorder.new
       #
       # NOTE: record might be sent more than once per test.  It will be
       # sent once with the results from the test itself.  If there is a
@@ -1476,7 +1476,7 @@ module Test
 
         OptionParser.new do |opts|
           opts.banner  = 'minitest options:'
-          opts.version = MiniTest::Unit::VERSION
+          opts.version = Test::Unit::Runner::VERSION
 
           opts.on '-h', '--help', 'Display this help.' do
             puts opts
@@ -1589,7 +1589,7 @@ module Test
 
       alias mini_run_suite _run_suite
 
-      # Overriding of MiniTest::Unit#puke
+      # Overriding of Test::Unit::Runner#puke
       def puke klass, meth, e
         # TODO:
         #   this overriding is for minitest feature that skip messages are
diff --git a/tool/lib/test/unit/assertions.rb b/tool/lib/test/unit/assertions.rb
index 29ace55d1d..711d8a6bc3 100644
--- a/tool/lib/test/unit/assertions.rb
+++ b/tool/lib/test/unit/assertions.rb
@@ -596,7 +596,7 @@ module Test
       # Takes a block and wraps it with the runner's shared mutex.
 
       def synchronize
-        MiniTest::Unit.runner.synchronize do
+        Test::Unit::Runner.runner.synchronize do
           yield
         end
       end
diff --git a/tool/lib/test/unit/parallel.rb b/tool/lib/test/unit/parallel.rb
index a223a9ece6..b0d8262bfc 100644
--- a/tool/lib/test/unit/parallel.rb
+++ b/tool/lib/test/unit/parallel.rb
@@ -34,10 +34,10 @@ module Test
 
       def _run_suite(suite, type) # :nodoc:
         @partial_report = []
-        orig_testout = MiniTest::Unit.output
+        orig_testout = Test::Unit::Runner.output
         i,o = IO.pipe
 
-        MiniTest::Unit.output = o
+        Test::Unit::Runner.output = o
         orig_stdin, orig_stdout = $stdin, $stdout
 
         th = Thread.new do
@@ -58,7 +58,7 @@ module Test
           result = [nil,nil]
         end
 
-        MiniTest::Unit.output = orig_testout
+        Test::Unit::Runner.output = orig_testout
         $stdin = orig_stdin
         $stdout = orig_stdout
 
@@ -79,7 +79,7 @@ module Test
         _report "done", Marshal.dump(result)
         return result
       ensure
-        MiniTest::Unit.output = orig_stdout
+        Test::Unit::Runner.output = orig_stdout
         $stdin = orig_stdin if orig_stdin
         $stdout = orig_stdout if orig_stdout
         o.close if o && !o.closed?
diff --git a/tool/lib/test/unit/testcase.rb b/tool/lib/test/unit/testcase.rb
index 61877803de..bbba87f63b 100644
--- a/tool/lib/test/unit/testcase.rb
+++ b/tool/lib/test/unit/testcase.rb
@@ -111,7 +111,7 @@ module Test
       #     end
       #   end
       #
-      #   class MiniTest::Unit::TestCase
+      #   class Test::Unit::Runner::TestCase
       #     include MyMinitestPlugin
       #   end
 
@@ -230,7 +230,7 @@ module Test
 
       def io
         @__io__ = true
-        MiniTest::Unit.output
+        Test::Unit::Runner.output
       end
 
       ##