(Possibly) The World's Smallest Ruby Unit Test Tool

tests.rb

require './tinytest'

class MyTests < TinyTest
  def setup
    @name = "Bob"
  end
  
  def teardown
    @name = ""
  end
  
  def test_name_length_is_greater_than_zero
    assert @name.length > 0
  end
  
  def test_name_length_is_greater_than_ninety_nine
    assert @name.length > 99
  end
  
  def test_name_begins_with_b
    assert @name[0].downcase == "b"
  end
end

class LookNoTests < TinyTest
  def not_a_test_method
  end
end

the_results.txt

$ ruby tests.rb 
.F.

Failed Tests:
MyTests#test_name_length_is_greater_than_ninety_nine, tests.rb:17

2 passed, 1 failed

tinytest.rb

class TinyTest
  def assert(result)
    raise caller.first unless result == true
  end
end
at_exit do
  @pass_count, @fail_count, test_classes, failures = 0, 0, [], []
  ObjectSpace.each_object(Class) { |obj| test_classes << obj if obj.ancestors.include?(TinyTest) && obj != TinyTest && obj.instance_methods.select {|method_name| method_name =~ /^test_/}.size > 0 }
  test_classes.each do |test_class|
    test_class.instance_methods.select {|method_name| method_name =~ /^test_/}.each do |test_method_name|
      begin
        tc = test_class.new
        tc.setup if tc.respond_to? :setup
        tc.send test_method_name.to_sym if tc.respond_to? test_method_name.to_sym
        tc.teardown if tc.respond_to? :teardown
        @pass_count += 1
        print "."
      rescue => e
        @fail_count += 1
        failures << "#{test_class.name}\##{test_method_name}, #{e.message.scan(/^(.*):/).flatten.first}"
        print "F"
      end
    end
  end
  puts "\n\nFailed Tests:"
  failures.each {|failure| puts failure}
  puts "\n#{@pass_count} passed, #{@fail_count} failed"
end