Hi,

It is an extemely difficult condition to come up with Testcases without SRS. But in some cases it so happens that the BA / Dev team is still in process of freezing requirements but the testing phase schedule has already commenced.

One probability would be incase you have a earlier build or a document listing the navigational flows, based on that you could come up with outline of the Test Scenarios. Also incase Dev team is able to send across Business / Release Notes even in an mail, it wouldm suffice to base your testcases on.

You would of course miss out the validation / Business Rule part which would could later be added once SRS / FRS is available. Incase SRS is not provided yet, you might use the Usecases / User Manual / Business Notes by Developers to understand the outline of the application.

However, testcases minus SRS would only be a rough draft and cannnot be trusted to complete extent.

Cheers.....