TESTNG:
    1. @DataProvider annotation
    2. Excel file with the help of Apache POI
    3. JSON or CSV file for API testing
    4. Data which comes from Database and stores in collections

    To use the DataProvider feature in the test cases,
    you have to declare a method annotated by 
    @DataProvider and then use the said method 
    in the test method using the ‘dataProvider‘
    attribute in the @Test annotation.