There are several phases to the test process starting with functional testing, followed by non-functional testing and leading onto the final stage of acceptance testing.
The Functional Testing involves testing either an element of a product or service (a function) or the complete product or service (all functions). This testing is used to determine whether the product or service will work as planned.
The Non-Functional testing stage is involved with looking at how a product or service behaves, along with whether the behaviour is appropriate and whether the behaviour is acceptable. These behaviours can then be viewed as either expected or not expected.
For more information see the 'Introduction to Testing' course
Acceptance testing involves ascertaining whether the product or service is what is expected by the end user of that product or service or their representative.
Unlike functional and non-functional testing, acceptance testing does not need to be an exhaustive set of tests, instead acceptance testing is generally a subset of tests, carried out to assess whether the main elements of the products or services are as expected, that is, acceptable.
It's important to note, in any organisation there are no set global rules to testing which organisations need to conform to. There may be certain standards which require an element of testing to be conducted but generally, organisations decide the types of testing they conduct and the level of testing done.
Many organisations may rely just on acceptance testing as there only form of testing, totally leaving out functional and non-functional testing, whilst others may pursue a more rigid form of testing, encapsulating all three major testing stages.
There are no global testing standards which all organisations follow
The level of risk increases as the level of testing falls, with many organisations running the chance of delivering products and services which simply may not be up to the expectation demanded from them.
Functional Testing looks at how a product or service works
Non-Functional Testing concentrates on the behaviours of a product or service
Acceptance testing is checking to see if the product or service is acceptable
There are no global testing standards and testing can vary from one organisation to the next
Risk increases as the level of testing falls