It is widely believed that automation greatly helps to find software bugs but it is not like that. Automation is not meant for defect detection! Testing focuses on uncovering bugs but automation does not!
It is true that testing activities are aimed at identifying defects; but, you must not confuse the perception with “test automation”. According to the interpretation of Cambridge Online Dictionary, automation is defined as this: “to make a process in an office or factory operate by computers or machine so that to lower volume of work performed by people and the time spent on the work.” Thus, it would be logical to conclude that test automation is an activity carried out to save on effort and achieve operational efficiency goals.
So, you should not consider that professional services automation is accountable for finding defects. On the contrary, it is necessary to declare it to be unfit for reduction of test effort and improvement of manual testing effectiveness. Automation by its nature does not use particular intelligent logic to uncover defects/bugs – it is common for manual testing activity. It (automation) combines technology used for simulating behavior of a real user (as much as possible) and written procedures, and, for this reason, it is not right to refer to automation as a bug detection process.
From another point of view, software test automation services appear to be much more effective when are used for regression tests. Put the other way round, automation brings good returns when the system being tested is mature/stable (thus, maintenance efforts require less time) and test cases are frequently executed. In regression testing, the testers are rather more interested in having 100% pass ratios (high-quality evidence) than tracking and finding a huge number of defects (low-quality evidence). Of course, they feel like discovering critical bugs, however, the primary objective is to have a clear and smooth run without any problems.
Automation software testing as a service is in high demand especially when it comes to regression testing that involves seeking new bugs in software apps and separating them. Analyzing an automated regression test suite you are able to observe zero defects and only some critical / major bugs, but not to find as many defects as possible.
Moreover, automated test cases help to understand that a system is functionally correct while manual testing can only show a system’s failures.