Package not compatible with Spring 13 release - two test classes errors out.

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Unit Test StringUtilTest.cls and SetutilTest Apex classes.
2. Received the following output.
Test failure, method: al.SetUtilsTest.testObjectToBlob -- System.Exception: 
null stack External entry point

Test failure, method: al.SetUtilsTest.testToStringBlobSet -- System.Exception: 
null stack External entry point
(al)

Test failure, method: al.StringUtilsTest.testJoinSetBlobSet -- 
System.Exception: null stack External entry point
(al)
3.

What is the expected output? What do you see instead?
Tests should pass

What version of the product are you using? On what operating system?
managed package 1.6

Please provide any additional information below.

Original issue reported on code.google.com by [email protected] on 15 Jan 2013 at 6:48