I was asked to provide estimates on how long the tasks would take in QA standpoint. Should the defects that might be encountered be considered? Or should I assume that the tasks would be defect-free? I would be really thankful if I could get some pointers or readings that would help me understand the process.
I'd say you (almost) always need to count with some additional time spent on defects. Whether or not you specifically say so (as in creating a special task for it), it's a different question.
I was asked to provide estimates on how long the tasks would take in QA standpoint. Should the defects that might be encountered be considered?
I can see at least two approaches:
you give one estimate where you take into account possible defects
you give an estimate without time for defects, but each of these defects will later get their own estimate (they might be attended to in the next iteration)
Whether you choose 1. or 2. depends on how you work in the company.
Yes, I would take previous test cycles and number of defects with this team, product or developer in a account. If it is new team/product make a guesstimate based on your previous experience.
I never had a test run where I didnt find a defect, or struggled with the configuration, infrastructure, and or setup to be able to start testing.
This estimate cannot be precise, my delivery estimates (including testing and fixing defects) are between -50% and +500% ;-) Estimating software development from idea to production is hard.
Should the defects that might be encountered be considered?
If your development process support this then yes - estimate the time to reproduce and write them down.
Or should I assume that the tasks would be defect-free?
As we (development team) are only human and there is always a chance to have defects in the code and thus should be taken into consideration when estimating.