Difference in [Mini]Test::Unit runner output between two machines

MacBook Air

$ rake
/Users/ross/.rbenv/versions/2.0.0-p247/bin/ruby -I"lib:test" -I"/Users/ross/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib" "/Users/ross/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/rake_test_loader.rb" "test/unit/basic_stat_request_packet_test.rb" "test/unit/basic_stat_request_test.rb" "test/unit/basic_stat_response_packet_test.rb" "test/unit/handshake_request_packet_test.rb" "test/unit/handshake_request_test.rb" "test/unit/handshake_response_packet_test.rb" "test/unit/int_stringz_test.rb" 
Loaded suite /Users/ross/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/rake_test_loader
Started
.........

Finished in 0.0271 seconds.

9 tests, 21 assertions, 0 failures, 0 errors, 0 pendings, 0 omissions, 0 notifications
100% passed

332.10 tests/s, 774.91 assertions/s

Retina MacBook Pro

$ rake
/Users/ross/.rbenv/versions/2.0.0-p247/bin/ruby -I"lib:test" -I"/Users/ross/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib" "/Users/ross/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/rake_test_loader.rb" "test/unit/basic_stat_request_packet_test.rb" "test/unit/basic_stat_request_test.rb" "test/unit/basic_stat_response_packet_test.rb" "test/unit/handshake_request_packet_test.rb" "test/unit/handshake_request_test.rb" "test/unit/handshake_response_packet_test.rb" "test/unit/int_stringz_test.rb" 
Run options: 

# Running tests:

Finished tests in 0.027775s, 324.0324 tests/s, 756.0756 assertions/s.                                               
9 tests, 21 assertions, 0 failures, 0 errors, 0 skips

ruby -v: ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-darwin13.0.1]