When to Start Testing and When to Stop Testing ?

When to Start Testing ?

An early start to testing reduces the cost, time to rework and error free software that is delivered to

the client.

However in Software Development Life Cycle (SDLC) testing can be started from the Requirements Gathering phase and lasts till the deployment of the software. 

For example in Water fall model formal testing is conducted in the Testing phase, but in incremental model, testing is performed at the end of every increment/iteration and at the end the whole application is tested.

When to Stop Testing?

Unlike when to start testing it is difficult to determine when to stop testing, as testing is a never

ending process and no one can say that any software is 100% tested. 

Following are the aspects which should be considered to stop the testing:

oTesting Deadlines.

oCompletion of test case execution.

oCompletion of Functional and code coverage to a certain point.

oBug rate falls below a certain level and no high priority bugs are identified.

oManagement decision.