It took me a little trial and error to get everything to work, but I fixed it by switching to spork-minitest and using the master branch of guard-minitest. Here's my test suite:
group :test, :development do
gem 'capybara'
gem 'database_cleaner'
gem 'awesome_print'
gem 'turn'
gem 'guard'
gem 'guard-spork'
gem 'guard-minitest', github: 'guard/guard-minitest'
gem 'guard-livereload'
gem 'terminal-notifier-guard'
gem 'capybara_minitest_spec'
gem 'rb-fsevent', '~> 0.9.1'
gem "spork-minitest", git: "https://github.com/semaperepelitsa/spork-minitest.git"
gem 'miniskirt'
gem 'minitest-spec-rails'
end
Thanks for the help anyway.