DZone

Every software product deals with some form of data input that comes from either the user or an external system. It is imperative that execution of test cases is done with carefully crafted test data that mimics the expected input data to ensure optimal test coverage.

Test data can be anything you can think of, such as user credentials, input/output data, uploaded files, database tables, etc. The test data need not be hard-coded into the test framework in case of automated testing. It can be imported from external files (Excel, JSON, properties file, or even plain text files) or data sources and fed into our automated test cases. The test steps iterate for the data and consequent rows of data are fed to the test steps as input.

Source: DZone