Many people have an idea that testing is not a mandatory task for an application which is in development or has been developed but I think that testing equally plays the same roles as development in the successful launch of the application. If the developer takes 50 hours to develop any application then 50 hours should also be given to tester to test the whole application.
The testing task should begin from the requirement gathering phase only. Although we all say that we are working on agile methodology and according to agile, testing tasks run parallel with the development. Do, we all follow the same ? Many people think that how anyone can test the application when it is in development phase only ? They have the idea that testing is just to put the valid values in the textbox and click submit button. If 404 error or any weird page appears then this means that developer had not worked well on the project and if the correct page appears then this means that the application is working fine. I just want to tell those people that testing activity is just checking the pages and links in an application.
Tester starts his testing from the very initial phase. During the requirement discussion, tester thinks the expected condition of every small functionality. Even if there is a click action then he thinks that what all pages user can navigate after clicking the link. He thinks both the negative and positive scenario of any functionality. Every tester follow the below process for the smallest functionality.
Testing has its own process and tester follow that process to make your application bug free. The process of testing is as follows:
Freeze the functionality
Write the expected result
Note the given condition
Compare the expected result with the given condition