Test scripts are required to make sure an effective testing approach is undertaken, where tests are repeatable, that is, the testing done by one person, is the same as that done by many people. If testing is not repeatable then the results produced are not reliable.
An effective method of capturing the results from the tests is also required, so tests can be assessed to see if they have been successful or not.
There are no hard and set rules for how test scripts are developed, with different organisations using different in-house standards, to develop UAT scripts.
Simple test scripts involve just a series of instructions, so a simple test script for user acceptance testing a television remote control could be,
1. Press the 'Standby' button
2. Press the 'Channel' button 5 times
3. Press the 'Volume +' button 4 times
These are just a simple set of instructions and it's these instructions which form the steps of the User Acceptance Tests.
After each step or series of steps, the expected result should be listed. That is, after step 1, above has been carried out, for example, what is the expected result?
Well, it's for the television to switch on, so if this is what does happen, then the test can be construed as being successful. If the television fails to power on, then the test can be construed as failed.
The results from the tests can be recorded, using a simple form or even a list, as shown below.