Testability of a requirement

I was being asked in one of the interviews the following questions:

How do you know requirement is testable?
How do you dig out the changes in requirments?

Please me find answers to these

[QUOTE=kamalsingh;14092]I was being asked in one of the interviews the following questions:

How do you know requirement is testable?
How do you dig out the changes in requirments?

Please me find answers to these[/QUOTE]

Requirement document should contains the word "Should" not the "may be".If there each and every requirement is clearly explained then SRS is testable otherwise not.

[B]How do you know requirement is testable?:-[/B]

To help discover untestable requirements, ask yourself how you would prove a requirement has been met. Either rewrite untestable requirements or find proxies for them

I have four loose criteria I use do judge "done".

Are the requirements sufficient to answer the question at hand?
Are they appropriate given the next consumers?
Do they meet basic goodness checks?
Is the feedback from key stakeholders positive?
The summary of these four areas, the bottom line, is: Are the requirements able to convey information to the next person so that they can do their job correctly? That is all I really need for requirements. The consumer needs information to do their job. Everything else is just an aid to get the information there in a correct, usable state.