MiniTest::Spec matchers cheat sheet. (from: mattsears.com/articles/2011/12/10/minitest-quick-reference)

MiniTest::Spec Cheat Sheet

#Assertion                Examples

must_be                   list.size.must_be :==, 0
must_be_close_to          subject.size.must_be_close_to 1,1
must_be_empty             list.must_be_empty
must_be_instance_of       list.must_be_instance_of Array
must_be_kind_of           list.must_be_kind_of Enumerable
must_be_nil               list.first.must_be_nil
must_be_same_as           subject.must_be_same_as subject
must_be_silent            proc { "no stdout or stderr" }.must_be_silent
must_be_within_epsilon    subject.size.must_be_within_epsilon 1,1
must_equal                subject.size.must_equal 2
must_include              subject.must_include "skinny jeans"
must_match                subject.first.must_match /silly/
must_output               proc { print "#{subject.size}!" }.must_output "2!"
must_respond_to           subject.must_respond_to :count
must_raise                proc { subject.foo }.must_raise NoMethodError
must_send                 subject.must_send [subject, :values_at, 0]  
must_throw                proc { throw :done if subject.any? }.must_thow :done