?The Framework is a tiered organization of the function 
libraries.?

In other words, our Test Automation Script contains simply 
calls to functions instead of individual statements. These 
functions are reusable and any Test Script can be 
constructed by simply calling these functions.

The code for these Library functions is found in the next 
tier(level). The functions themselves might have been 
defined in terms  of another set of functions, which are 
again described in the next tier.

This is called automation framework. It can be 2-tier, 3-
tier,... n-tier.

A test automation framework is a set of assumptions, 
concepts, and practices that provide support for automated 
software testing. This article describes and demonstrates 
five basic frameworks.


There is no hard and fast rule to use a specific Automation 
frame work. It all depends on your project needs, here are 
some info on the same.

Data Driven approach is suitable for applications that have 
limited functionality but large number of variations in 
terms of test data.

Functional Framework is suitable for applications that have 
variety of functionality but limited variations in terms of 
test data.

Hybrid Test Automation Framework is suitable for 
applications that have variety of functionality and larger 
number of variations in terms of test data.

Record, enhance and play back methodology is suitable to 
convert small to medium size manual scripts into equivalent 
automation scripts - one to one basis.