Testing - Difference between Ad-hoc Testing, Monkey Testing and Exploratory Testing

• What is the difference between Ad-hoc Testing, Monkey Testing and Exploratory Testing?

• "Exploratory Testing" involves simultaneous learning, test design and test execution. It is a type of "Ad-hoc Testing", but only difference is that in this case, the tester does not have much idea about the application & he explores the system in an attempt to learn the application and simultaneously test it.

• "Ad-hoc Testing" is performed without any planning of process and without any documentation like Test Case or Test Scenarios. It involves test design and simultaneous test execution. For Ad-hoc testing the testers possess significant understanding of the software before testing it. 

• "Monkey Testing" is done with no specific test in mind. Here the monkey is the producer of any input data (which can be either a file data or can be an input device data). It involves pressing some keys randomly and checking whether the software fails or not.