Updated: Sep 19, 2021
As the name suggests manual testing is performed without the help of any tools whereas automation testing is performed with the help of automation testing tools. Some testing types can’t be performed manually so an automation testing tool is definitely required in such cases, for example performance testing can’t be performed manually so a tool is definitely required to perform performance testing.
If the project is short term then it is better to go for manual testing because setting up the automation testing framework itself takes lot of time, effort and money and if the project is short term then there is no point to invest resources for setting up the automation testing framework instead it is better to assign the testing tasks to the testers who perform the testing manually.
Also if the testing tasks are not repetitive then there is no point in investing resources for setting up automation testing framework because the main goal of automation testing is to create automation testing scripts that would run every time a change happens in the code (i.e. for every release of the code by the developer) just to see if the code is working fine. But if the application under test is such that the code change in one feature would not impact code in other features hence the goal of the project is just to retest the features that have a code change in the current release then it is better to go for manual testing because in any normal scenario code change would happen in different features every time and testing is required to be done on different features i.e. there is no repetitive testing hence no need for automation scripts in this case.
But if the project is long term and testing tasks are repetitive then it is advantageous to invest resources in building up a robust automation testing framework and every time a code change happens automation scripts would run automatically and perform the testing of the entire code even testing of those areas that have not been touched by the developer in the current release. And the reason why it is important to test every feature of the application even if it has not been impacted in the current project release is that generally when a code change happens in one feature it could impact other related features hence it is always better to regression test all the features that are directly or indirectly impacted in the current release.
Manual testing is performed manually by a team of testers depending on the size and duration of the project and automation testing is also performed by a team of testers depending on the size and duration of the project but using tools such as Selenium and Quick Test Professional (QTP) for regression testing, Jmeter and Loadrunner for Performance Testing, Jenkins and Quality Center for test management like running the automation testing scripts automatically as per the per-defined schedule and so on.
Selenium, Jmeter and Jenkins are open source tools i.e. they are available for free to be used by anybody whereas QTP, Loadrunner and Quality Center are paid tools by MicroFccus Company and you need to buy a license to use these tools.
So in conclusion it all depends on many factors such as budget of the project, duration of the project, knowledge of the people who are working on the project etc. which decides whether the company would go for manual testing or automation testing for their project.
But it doesn’t matter whether the company would opt for manual testing or automation testing, the ultimate goal of testing remains the same and it is to test the software for bugs so that end users who will finally be using the software would not face any issues because the cost of fixing the bugs that are reported by the end users is much higher than the cost of finding and fixing the bugs which are caught during the early stages of the software development.