Since I am writing a seminar work on "Transaction Processing in MS Azure" for my university I wanted to launch a bank-transfer simulation. I already have implemented a getting-started thingy to get familiar with Azure: http://www.c-sharpcorner.com/UploadFile/dhananjaycoder/48/Default.aspx . Question: What is the most easy way (using SQL Azure) to implement a small app which (dis)proves that transactions in Azure are done properly? (e.g. no lost updates)
SQL Azure has an identical processing to SQL Server - only restricted to a very large subset of what's available in SQL Server. So you can re-phrase your question as: how do you prove the correctness of transaction handling in SQL Server.
Well, the unfortunate answer is: you can't prove correctness, you have to trust MS on that one.
Obviously, you could come with stress situation trying to "trick" the RDBMS into corner situation to see if transactions keep being respected, but not being able to find a bug does not prove that no bug could be found.
Finally, I would that atomic transactions is one of the critical feature of either SQL Azure or SQL Server (a long long established MS product), hence you can have a very high confidence, that it's done right.