Using test block in unit testing

I saw some code using a block like:

test "describing the test" do
  assert true
end

in unit test code.

But I can't get it to work. Is there any thing to do (requiring a gem)?

This is an alternative way to write

def test_describe_the_test
  assert true
end

right?

I can't find good documentation on how to use this.

I saw some code using a block like:

test "describing the test" do
assert true
end

in unit test code.

But I can't get it to work. Is there any thing to do (requiring a
gem)?

What version of rails are you using? That was added to the as yet
unreleased rails 2.2.

Fred