A while back I wrote a proof of concept isIn functionality injector that seemed to work fairly decently. I even wrote some tests for it that it passed with flying colors. Being a proof of concept I never really used it and never ran into the danger of using that functionality. Recently I downloaded the trial for FDT and since it doesn't have the same type of FlexUnit integration that FlashBuilder 4 has I had to get my tests working differently. When I got the tests up an running my tests for the isIn functionality blew up in spectacular fashion. They didn't just fail, the took the whole unit test display down with them. This was the same class and tests that passed cleanly before. What happened?
It turns out messing with the prototype of Object to solve a problem is like fighting fire with a nuclear explosion. It will probably work but cause serious problems throughout the system. So, following the test driven development methodology of red, green, refactor I saw that it was a time for a refactor. Well that and it was now a red test that I wanted to make green.
I came up with a solution that I think is better. It is more flexible than before, since you can select the class you want to add the functionality to. Even better, you can remove the functionality after you add it. Since I've begun to move my code over to GitHub you can find the new code over at https://github.com/darylducharme/Ducharme-Media-Code/tree/master/src/cc/ducharme/utils. The new test class is available at https://github.com/darylducharme/Ducharme-Media-Code/blob/master/test-src/utils/IsInTests.as
You may notice that the last test - dictionaryEnumerationTest() at this time - is new. This is the test that checks the problem that I found that was not being tested before. If you are writing tests and find a hole in your tests later, it is always recommended to add new tests to keep you from having the same problem in the future.
Hopefully, someone out there can learn from my mistakes on this occasion. Also, the new isIn class and its static functions are a whole lot more useful than what I had written before. Perhaps someone out there can put it to good use. What do you think?