What is Test data and how to prepare it?

Test data is the data which we use while testing. The data we use to give in system while doing the testing is called test data.  Selecting the test data is very important activity. Mostly for positive flow, tester should use the data which would be used in live production environment. So this helps to capture the bugs which may arises due to the data.  Most of the bugs are related to the data, mean when we give the input data to the software, it produces the output in the form of some data, we verify the output data and compares it with the expected data.

The data we give to system is called input data and the data system produces after subjecting to input data is called output data. for example of input data and output data.

Take the example of search box, see when we enter the content which we called as test data, for that system will produce the output which we called output data, here from above image you can see that for test data system produced the output which we called as output data.

In test cases we write the actual and expected result, mean when we provide particular data to system, then system should provide the expected output.

Test data can be created before the test execution or we can create the test data while testing also, it’s totally depends on the situation. Mostly test data is created before the test execution as there is activities like test scenario creation, test cases creation and then test data creation. For all scenarios, its not mandatory that we should have test data, there might be some situation where test data is not needed or can’t be created.

Test data should also include some invalid data, this is to test that how system would response such a invalid test data, system should handle it without breaking. So it is important to include the invalid test data also. Some time when system is subjected to the invalid data, system get crashed. Example of invalid data is, for login putting invalid user name, for mobile number test box, invalid data would be entering the negative number, character etc. test data should be enough and should contain whole range, here whole range means it should cover all possible data. For example, we can think about ecommerce site where user can purchase the goods but what is the upper limit for user for purchasing the goods? Is it 1 lakh or 2 lakh or 1 crore or 10 crore, which amount is out of the range etc. things should be considered properly.

We can provide the test data to system by its UI or may any external files (excel, doc, csv etc.), or by using the database. Similarly system can generate output data on UI or in excel file etc. test data is very important is testing, it need to be selected accurate.