What is Integartion testing?

Individual components are combined with the other components , validate the communications,data sharing and links occurs the properly.
Integration testing : Divide into the following  three approaches

• all-at-once
• bottom-up       
•  Top-down           

     Bottom up: Integration testing start from the low level components and end with the high level components.
     Top down: Testing will start from the lop Integrated level modules and connect to the branch level modules.
     all-at -once : it will Combine both top level and botton level members.