# Unequal equality **URL:** \ **Category:** Ruby\ **Created:** [October 15, 2010, 10:39pm UTC](https://www.ruby-forum.com/t/unequal-equality/197555 "2010-10-15T22:39:48Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Dobai-Pataky\_BSSSSl](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/77aa72/32.png) [@Dobai-Pataky\_BSSSSl](https://www.ruby-forum.com/u/Dobai-Pataky_BSSSSl)\ **Post date:** [October 15, 2010, 10:39pm UTC](https://www.ruby-forum.com/t/unequal-equality/197555/1 "2010-10-15T22:39:48Z")
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? ---
**Author:** ![felix.leg](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/c89c15/32.png) [@felix.leg](https://www.ruby-forum.com/u/felix.leg)\ **Post date:** [October 15, 2010, 10:39pm UTC](https://www.ruby-forum.com/t/unequal-equality/197555/2 "2010-10-15T22:39:48Z")
On 10/15/2010 11:45 AM, felix.leg wrote: > ./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? Probably it’s due to IEEE floating point inaccuracy. Try using assert\_in\_delta instead of assert\_equal whenever you compare floats in a test. ---
**Author:** ![felix.leg](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/c89c15/32.png) [@felix.leg](https://www.ruby-forum.com/u/felix.leg)\ **Post date:** [October 15, 2010, 10:39pm UTC](https://www.ruby-forum.com/t/unequal-equality/197555/3 "2010-10-15T22:39:48Z")
On Oct 15, 2010, at 11:45 , felix.leg wrote: > 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? Welcome to floating point math. Equality is a no-no with floats. What you want is assert\_in\_delta.