Business Layer Testing and Data Layer Testing

Business Layer Testing:-
 

Business layer testing focuses on finding errors in the business logic of your Internet application. You will find this layer very similar to testing stand-alone applications in that you can employ both white and black-box techniques. You will want to create test plans and procedures that detect errors in the application’s performance requirements, data acquisition, and transaction processing. You should employ white-box approaches for components developed in-house because you have access to the program logic. However, black-box testing techniques are your primary testing approach for this layer. You will start by developing test drivers to unit-test the individual components. Next, you can perform a system test to determine whether all the components work together correctly. When conducting a system test for this layer, you need to mimic the steps any user performs when purchasing a Software product or service. For example, for an e-commerce site you may need to build a test driver that searches inventory, fills a  hopping cart, and checks out. Pragmatically modeling these steps can prove challenging. The technologies that you use to build the business logic dictate how you build and conduct your tests. There are numerous technologies and techniques you may use to build this layer which makes it impossible to suggest a cookie-cutter testing method. For instance, you might architect your solution using a dedicated application server such as JBoss. Or you could have
stand-alone CGI modules written in C or Perl.
Regardless of your approach, there exist certain characteristics of your application that you should always test. These areas include the following: 
• Performance. Check to watch whether the application meets documented performance
  specifications (Normally specified in response times and throughput rates).
• Data validity. Test to find errors in data/Information collected from customers.
• Transactions. Check to uncover errors in transaction processing, which may include items
  like credit card processing, e-mailing verifications, and calculating sales tax.

Data Layer Testing:-

Once your site is up and running, the data you collect become very valuable. Credit card numbers, payment information, and user profiles are examples of the types of data you may collect while running your e-commerce site. Losing this information could prove disastrous and crippling to your business. Hence, you should have to develop a set of procedures to protect your data storage systems.
During Testing of the data layer, it consists primarily of testing the database management system that your application uses to store and retrieve information. Small sites data in text files, but complex sitesuses full-featured enterprise-level databases. Depending upon your needs, you may use both approaches.
One of the most challenge associated with testing this layer is duplicating the production environment. You must use equivalent hardware platforms and software versions to conduct valid tests. Inadditio      QL] INSERTs, UPDATEs, and DELETEs),
queries(SELECTs), and transactions.
• Data integrity. To Verify that correct and accurate data is stored.
• Fault tolerance and recoverability. Maximize the MTBF and minimize the MTTR.