Agile Testing

To talk about Agile Testing is necessary  knowing the principles and values of the Agile methods.The values defined in the Agile Manifesto are the following:
Individuals and interactions over processes and tools
Working software over comprehensive documentation
Customer collaboration over contract negotiation
Responding to change over following a plan

What do we mean by Agile Testing?

When we say "Agile Testing" we're usually talking about business-facing tests defined for the business experts.This include test the product and focus on discovering what might be lacking in the finished product to we can improve it.
Agile testing doesn't just mean testing on agile project. Some testing approaches such as exploratory testing, are inherently agile whether it's done an agile project or not.