Pig unit tests failures due to expected results ordering

[Cheung, Po]

We are seeing a number of Pig 0.8.1 unit test failures with Apache Hadoop 0.22 
due to differences in the ordering of the expected results.

For example, in TestCombiner.testJiraPig746, the expected result is:

                
"(pig1,75,{(pig1,18,2.1),(pig1,18,2.1),(pig1,19,2.1),(pig1,20,3.1)})",

But the actual result is:

                
"(pig1,75,{(pig1,20,3.1),(pig1,19,2.1),(pig1,18,2.1),(pig1,18,2.1)})",

Other similar test failures related to ordering include:
                TestCommit.testCheckin2
                TestEvalPipeline2.testOrderByLimitJoin
                TestMultiQuery.testMultiQueryJiraPig1113

Are these valid test issues or is there something obvious I am missing?

Thanks,
Po