what is the difference between Integration Testing and Unit Testing ?

Answer 1

this is what we define it as...

integration testing = a test to see if it works with our system

unit testing = a test to see if it works all by itself

Answer 2

In Unit Testing, you test a component or part of a software application to see if it works correctly by itself. Many developers use a Unit Test Framework such as JUnit for Java (other languages have other framework) to accomplish this kind of testing.

In Integration Testing, you test the combined components/parts of a software application to see if they function correctly together, as a whole. As such, integration testing is typically done after unit testing and is more common for distributed applications (tiered, client/server, internet applications).