Remove MiniTest workaround

Author: pirj

lib/rspec/core/minitest_assertions_adapter.rb

@@ -1,9 +1,9 @@
 begin
-  # Only the minitest 5.x gem includes the minitest.rb and assertions.rb files.
+  # Only Minitest 5.x includes minitest.rb and assertions.rb files
   require 'minitest'
   require 'minitest/assertions'
 rescue LoadError
-  # We must be using Ruby Core's MiniTest or the Minitest gem 4.x.
+  # We must be using Minitest 4.x
   require 'minitest/unit'
   Minitest = MiniTest
 end

lib/rspec/core/test_unit_assertions_adapter.rb

@@ -6,24 +6,9 @@ module Core
     module TestUnitAssertionsAdapter
       include ::Test::Unit::Assertions
 
-      # If using test/unit from Ruby core with Ruby 1.9+, it includes
-      # MiniTest::Assertions by default. Note the upcasing of 'Test'.
-      #
-      # If the test/unit gem is being loaded, it will not include any minitest
-      # assertions.
-      #
-      # Only if Minitest 5.x is included / loaded do we need to worry about
-      # adding a shim for the new updates. Thus instead of checking on the
-      # RUBY_VERSION we need to check ancestors.
-      begin
-        # MiniTest is 4.x.
-        # Minitest is 5.x.
-        if ancestors.include?(::Minitest::Assertions)
-          require 'rspec/core/minitest_assertions_adapter'
-          include ::RSpec::Core::MinitestAssertionsAdapter
-        end
-      rescue NameError
-        # No-op. Minitest 5.x was not loaded.
+      if defined?(::Minitest::Assertions) && ancestors.include?(::Minitest::Assertions)
+        require 'rspec/core/minitest_assertions_adapter'
+        include ::RSpec::Core::MinitestAssertionsAdapter
       end
     end
   end