First off, MavensMate is the Bomb-digity yo!
Running Apex unit tests (any org, any test) results in json-ified output like that below instead of the sexy failure / success message one expects from the amazingness that is mavensMate.
additionally, no coverage information is listed, etc.
I'm using the latest version of the gem, and i ran update mavensmate early this morning (10/1) As you can see, I'm hitting the rvm version of ruby currently at 1.9.3-p125
--start output--
{"success":false,"message":"undefined method []' for nil:NilClass(erb):56:in
block in render_to_string'\n(erb):55:in each'\n(erb):55:in
render_to_string'\n/Users/kpoorman/.rvm/rubies/ruby-1.9.3-p125-perf/lib/ruby/1.9.1/erb.rb:838:in eval'\n/Users/kpoorman/.rvm/rubies/ruby-1.9.3-p125-perf/lib/ruby/1.9.1/erb.rb:838:in
result'\n/Users/kpoorman/Library/Application Support/Sublime Text 2/Packages/MavensMate/support/tmvc/lib/application_controller.rb:146:in render_to_string'\n/Users/kpoorman/Library/Application Support/Sublime Text 2/Packages/MavensMate/support/lib/local_server.rb:113:in
do_POST'\n/Users/kpoorman/.rvm/rubies/ruby-1.9.3-p125-perf/lib/ruby/1.9.1/webrick/httpservlet/abstract.rb:106:in service'\n/Users/kpoorman/.rvm/rubies/ruby-1.9.3-p125-perf/lib/ruby/1.9.1/webrick/httpserver.rb:138:in
service'\n/Users/kpoorman/.rvm/rubies/ruby-1.9.3-p125-perf/lib/ruby/1.9.1/webrick/httpserver.rb:94:in run'\n/Users/kpoorman/.rvm/rubies/ruby-1.9.3-p125-perf/lib/ruby/1.9.1/webrick/server.rb:191:in
block in start_thread'
{:run_tests_response=>{:result=>{:failures=>{:id=>"01pW0000000CusXIAS", :message=>"line 55, column 51: Constructor not defined: [AgencyGridTemplateBuilderController].()", :method_name=>nil, :name=>"AgencyGridTemplateBuilderControllerTest", :namespace=>nil, :stack_trace=>nil, :time=>"-1.0", :type=>"Class"}, :num_failures=>"1", :num_tests_run=>"0", :total_time=>"0.0"}}, :log=>{:debugging_info=>{:debug_log=>nil}}}"}