You will have to require the file of the class you are testing.

Also, I suspect that you aren't testing a class named "Unit".

If you are testing a class named "Array", your class name would be  
"ArrayTest"

Another point to make: I don't think you have to write an  
"initialize" method at any point.  You can use setup() and teardown()  
(?), and use test_whatever for the actual tests.  I.e.

require 'test/unit'
require 'array'

class ArrayTest < Test::Unit::TestCase
   def setup
	@array = Array.new
   end

   def test_new_array_is_empty
   	assert @array.empty?
   end
end

Scott



On Apr 1, 2007, at 1:50 PM, aidy wrote:

> Hi
>
> I am trying to run some unit tests.
>
>
> <snip>
> require 'test/unit'
>
>
> class UnitTests < Test::Unit::TestCase
>
>   def initialize
>     assert(true)
>   end
>
> end
>
> UnitTests.new
> <snip>
>
> but i am receiving this error
>
> c:/ruby/lib/ruby/1.8/test/unit/testcase.rb:117:in `add_assertion':
> undefined method `add_assertion' for nil:NilClass (NoMethodError)
>
> could anyone help?
>
> aidy
>
>