Testing Rake Tasks

I'm somewhat new to RoR and I've found that along with my main RoR development work I've also developed a number of custom rake tasks that do various things. I'd like to be able to write unit tests for these rake tasks and I've done a fair bit of google but I haven't really seen it explained well how to go about doing that. The typical advice is to develop your task as a class to test the class, but how exactly is that done? I've developed my latest task as a class, and added the following code to test/unit:

class MyClassTest < Test::Unit::TestCase   def test_is_day_word     assert MyClassTest.is_day_word("Tuesday")   end end

However this throws:

  1) Error: test_is_day_word(MyClassTest): NameError: uninitialized constant MyClassTest::MyClass     /usr/local/lib/ruby/gems/1.8/gems/activesupport-2.1.0/lib/ active_support/dependencies.rb:492:in `const_missing'     ./test/unit/masstimes_crawl_test.rb:4:in `test_is_day_word'     /usr/local/lib/ruby/gems/1.8/gems/activesupport-2.1.0/lib/ active_support/testing/setup_and_teardown.rb:33:in `__send__'     /usr/local/lib/ruby/gems/1.8/gems/activesupport-2.1.0/lib/ active_support/testing/setup_and_teardown.rb:33:in `run'

What am I doing wrong and is there a better way to test rake tasks?