Test Data Generation (What, How to, Example, Tools)

Software TestingAutomation TestingTesting Tools

As a tester, you may assume that ‘Designing Test cases are tough enough, therefore why care about something as minor as Test Data’. The objective of this tutorial is to introduce you to Test Data, its relevance and offer practical tips and tactics to produce test data efficiently. So, let’s Begin!

What is Test Data in Software Testing?

Test Data in Software Testing is the input delivered to a software program during test execution. It represents data that impacts or is impacted by program execution during testing. Assess data is used for both positive testings to check that functions generate anticipated outcomes for given inputs and for negative testing to test software capabilities to handle odd, exceptional, or unexpected inputs.

In a tester's day-to-day existence, the word "test data" is often used. He requires certain data to enter when running test cases in order to achieve the anticipated results. Huge data is often necessary to load the program with data (Load testing) or to assess the application's breakpoint (Stress testing). This information might be correct or incorrect. In a nutshell, test data is information that is necessary to correctly execute test cases and validate the anticipated outcome in any software application under test.

Poorly constructed testing data may not test all feasible test situations which may affect the quality of the product.

What is the significance of this?

This example illustrates the need for test data. Let's imagine you want to test mobile software apps. To test mobile apps, you'll need a variety of input data, such as images in various formats, music files in both supported and unsupported formats, videos, contacts files, and various emails, among other things. Without this test data, the tester will be unable to continue testing and will not get the intended results.

Test Data Types

Test data may be divided into the following categories −

The term "blank files" or "no data" refers to files that have no data, i.e. no input to the program, and this ensures that the application handles exceptions and throws the appropriate error.

The term "valid set of test data" refers to the application's valid or supported files. When supplied as input, they should produce the anticipated result.

The term "invalid set of test data" refers to all of the unsupported file formats that are used to ensure that the program processes them all correctly and alerts the user with the appropriate error message.

Large amounts of test data for load, performance, and stress testing cannot be created during execution and must be prepared when setting up your test environment. For example, in order to load an application, a tester may need up to 10,000 distinct format files, which may be generated using an automated script or existing test data.

Data with all conceivable permutations of boundary values is included in the test data to ensure that all boundary criteria are met. If a text box can hold numbers 2-20, for example, enter 2 (minimum) and 20 (maximum) values. Boundary values are all those values that are barely adequate for the program to manage; if the tester goes past them, the application will break.

The ideal test data contains all possible permutations of data, ensuring that no serious flaws are overlooked.

What is Test Data Generation? Why test data should be produced before test execution?

Everybody understands that testing is a process that creates and consumes vast volumes of data. Data used in testing specifies the beginning circumstances for a test and is the channel via which the tester changes the program. It is a critical aspect of most Functional Tests.

Depending on your testing environment you may need to CREATE Test Data (Most of the time) or at least select an appropriate test data for your test cases (if the test data is already produced) (is the test data is already created).

Typically test data is prepared in sync with the test case it is meant to be utilized for.

Test Data may be Generated - 

  • Manually

  • Mass transfer of data from production to testing environment

  • Mass copy of test data from older client systems

  • Automated Test Data Generation Tools

Typically sample data should be produced before you begin test execution since it is difficult to handle test data management otherwise. Since in many testing environments producing test data needs numerous pre-steps or highly time-consuming test environment settings. . Also If test data creation is done when you are in the test execution phase you may overrun your testing deadline.

Below are presented numerous testing kinds coupled with some ideas about their testing data demands.

Test Data for White Box Testing

In White Box Testing, test data Management is obtained from the direct study of the code to be tested. Test data may be chosen by taking into consideration the following things −

  • It is desired to cover as many branches as feasible; testing data may be developed so that all branches in the program source code are tested at least once

  • Path testing: all pathways in the program source code are checked at least once - test data preparation may be done to cover as many instances as feasible

  • Negative API Testing −

    • Testing data may include improper parameter types used to invoke separate methods

    • Testing data may consist of erroneous combinations of parameters that are used to invoke the program’s methods

Test Data for Performance Testing

Performance Testing is the sort of testing which is conducted in order to assess how quickly the system reacts under a certain workload. The purpose of this form of testing is not to uncover flaws, but to reduce bottlenecks.

An essential feature of Performance Testing is that the collection of sample data utilized must be extremely near to ‘real’ or ‘live’ data that is used in production. The following issue arises: ‘Ok, it’s excellent to test using actual data, but how can I collect this data?’ The solution is very straightforward: from the people who know the best - the consumers. They may be able to supply some data they already have or, if they don’t have an existing collection of data, they may aid you by providing comments suggesting how the real-world data would look like.

In case you are in a maintenance testing project you might transfer data from the production environment onto the testing bed. It is a recommended practice to anonymize (scramble) sensitive client data like Social Security Number, Credit Card Numbers, Bank Details, etc. as the copy is produced.

Test Data for Security Testing

Security Testing is the procedure that examines whether an information system secures data from harmful intent. The collection of data that need to be developed in order to adequately assess software security must encompass the following topics −

  • Confidentiality − All the information given by customers is maintained in the highest confidentiality and is not shared with any other parties. As a simple example, if an application utilizes SSL, you may construct a collection of test data that confirms that the encryption is done successfully.

  • Integrity − Determine if the information given by the system is accurate. To develop relevant test data you might start by having an in-depth look at the design, code, databases and file structures.

  • Authentication − Represents the process of establishing the identification of a user. Testing data may be built as a distinct combination of usernames and passwords and its goal is to ensure that only the authorized persons are able to access the software system.

  • Authorization − Tells what are the privileges of a given user. Testing data may comprise a distinct mix of users, roles and actions in order to confirm only users with proper rights are able to do a certain operation.

Test Data for Black Box Testing

In Black Box Testing the code is not accessible to the tester. Your functional test cases may contain test data satisfying these requirements - −

  • No data − Check system reaction when no data is supplied

  • Valid data − Check system response when Valid test data is provided

  • Invalid data − Check system response when InValid test data is provided

  • Illegal data format − Check system reaction when test data is in an invalid format

  • Boundary Condition Dataset − Test data fulfilling boundary value conditions

  • Equivalence Partition Data Set − Test data certifying your equivalence partitions.

  • Decision Table Data Set − Test data qualifying your decision table testing approach

  • State Transition Test Data Set − Test data fulfilling your state transition testing approach

  • Use Case Test Data − Test Data in sync with your use cases.

Note − Depending on the software program to be tested, you may utilize part or all of the above test data creation

Automated Test Data Generation Tools

In order to produce diverse types of data, you may utilize a variety of automated test data generating technologies. Below are some examples of such tools −

DTM Test Data generator is a completely configurable program that creates data, tables (views, processes, etc) for database testing (performance testing, QA testing, load testing, or usability testing) reasons.

Datatect is a SQL data generator by Banner Software, provides a range of realistic test data in ASCII flat files or directly generates test data for RDBMS like Oracle, Sybase, SQL Server, and Informix.


In conclusion, well-designed testing data helps you to uncover and rectify severe issues in functioning. Choice of test data picked must be reevaluated in every step of a multi-phase product development cycle. So, constantly keep an eye on it.

Updated on 26-Nov-2021 05:12:56