Everyone knows the importance of test data while testing. A test case supported by ‘smart data’ results in uncovering useful information about product’s behavior.
While doing functional testing, most of us deal with text boxes and other input types, where a user can enter data that goes into the system. A dangerous or invalid data has potential to result in errors or unwanted behavior of the application. Please take a look at the Big List of Naughty Strings which is a list of strings that have a high probability of uncovering issues when used as user-input data. By using these strings, you must find out if your application is able to handle weird/invalid data.
Here's the link to access to the list: https://github.com/minimaxir/big-list-of-naughty-strings
blns.txt consists of newline-delimited strings and comments which are preceded with #. The comments divide the strings into sections for easy manual reading and copy/pasting into input forms. For those who want to access the strings programmatically, a blns.json file is provided containing an array with all the comments stripped out (the scripts folder contains a Python script used to generate the blns.json).