I've got such that output during testing my program:
[terminal_output]
Loaded suite ./niep_test
Started
....F.
Finished in 0.009922 seconds.

   1) Failure:
test_sanity(SFTester)
     [./niep_test.rb:12:in `sanity'
      ./niep_test.rb:19:in `test_sanity']:
<7.8e-11> expected but was
<7.8e-11>.

6 tests, 9 assertions, 1 failures, 0 errors
[/terminal_output]

A you can see the assert_equal function reports that something equal is 
not equal. WTF? Is it some bug in TestUnit package, or my program just 
looks to work fine?