Can Automation Testing replace Manual Testing ?

This is tricky situation to decide whether Automation can replace Manual testing ? whether all testcases of application should be automated? My opinion is automation is not a replacement of manual testing , we need to strike right balance between manual way of testing and automation. Manual Testing and Automation are mutually Inclusive.But sometimes management aggressively may claim their applications can be 100% automated without analysing that it might increase effort and reap no fruit .Before jumping into automation lets try to answer and understand few things.

What Needs to be Automated ?

Suppose there are around 500 testcases for an application , not all 500 should be automated.One has to identify testcases/features which are automatable, there is certain criteria to decide if testcases are automatable which we will discuss further.Out of 500 say 300 testcases are identified as automatable, then we can target to have 100% automation for those 300 testcases, rest 200 defintely needs human to test.Lets look at Criteria to decide which functionality or testcases are right candidates for automation.

Purpose of Automation ?

What are the reasons one has to go for automation is it to reduce efforts and increase efficiency? is it because its going to help in long run as your application is growing in size with new features ? If you go through below set of questions it brings more clarity.

a) Is it only one time requirement? not going to be used in future ? then its better not to automate these features

b) Is Application growing with newly added features? many regression test cases to be tested before every release.In this scenario it is best to Automate regression testcases to ensure every release stamps with best quality.Newly added features can be manually tested and part of them can be considered for automation as well.QA will be able to decide this.

c)Team has enough skills to automate? sometimes this could be also a deciding factor if team has good number of automation engineers , Does team need any trainings on skill set.

d)Time Constraint When there is a time constraint in delievry of the Application then its better to go for manual testing and management can derive strategy to plan phase wise automation for repetitive features.

How to Automate ?

One we understood WHAT and WHY of automation then its time to know HOW are we going to Automate the automatable features of application.Whether we need to build Automation framework from scratch or use some readily available tools in the market.Which features we are going for UI Automation and the tools/ programming required for it, which API's are we going to automate and the tools to choose from.Calculate ROI(Return on Investment) with automation activity you are going to take which helps to make wise deciscion so that automation gives a sense of confidence that there is maximum coverage of regression tests and existing features are not broken because of new feature addition.