less code, more software

This morning I spent a happy hour exploring a little of ruby's Test::Unit::TestCase. I started with this:

require 'test/unit'
class MyTest < Test::Unit::TestCase def test_one_plus_one_equals_two assert_equal 2, 1+1.1 end end 

I wanted to see how little I needed to write my own, super-minimal implementation of Test::Unit::TestCase...

require 'test/unit'
class MyTest < MyTestCase def test_one_plus_one_equals_two assert_equal 2, 1+1.1 end end 

After 204 traffic lights in cyber-dojo I ended up with this...

require 'assertion_failed_error'
class MyTestCase
 def self.test_names
 public_instance_methods.select{|name| name =~ /^test_/}
 end
 
 def assert_equal( expected, actual )
 message = 
 "#{expected.inspect} expected but was\n" +
 "#{actual.inspect}\n"
 assert_block(message) { expected == actual }
 end
 def assert_block( message )
 if (! yield)
 raise AssertionFailedError.new(message.to_s)
 end
 end
end
at_exit do
 ::ObjectSpace.each_object(Class) do |klass|
 if (klass < MyTestCase) klass.test_names.each do |method_name| begin klass.new.send method_name rescue AssertionFailedError => error
 print "#{klass.name}:#{method_name}:\n" +
 "#{error.message}"
 end
 end
 end
 end
end

class AssertionFailedError < RuntimeError; end 

which allowed me write...

require 'my_test_case'
class MyTest < MyTestCase def test_one_plus_one_equals_two assert_equal 2, 1+1.1 end end 

and finally, I added this...

class MyTestCase
 ...
 def self.test( name, &block )
 define_method("test_#{name}".to_sym, &block)
 end
 ...
end

which allowed me to rewrite the test as...

require 'my_test_case'
class MyTest < MyTestCase test "1+1 == 2" do assert_equal 2, 1+1.1 end end 

Fun :-)

[フレーム]