Integration and qualification tests for an application

[BrusterThemand]

I'm trying to realize a calculator using JAVA, so I'm following these stages:

1. Needs analysis (specifications)
2. UML diagrams
3. Programming
4. Unit testing
5. Integration and qualification tests

for Unit testing I'm using JUnit but I don't know what I'm gonna need to accomplish the fifth stage.

[Rhys69]

Integration testing -- also known as integration and testing (I&T) -- is a type of software testing in which the different units, modules or components of a software application are tested as a combined entity.

[Fuentes]

Integration testing -- also known as integration and testing (I&T) -- is a type of software testing in which the different units, modules or components of a software application are tested as a combined entity.