Functional Testing Explained with Test Cases & Examples

Every enterprise wants to achieve high-quality software that only functions as expected but also delivers a great experience to users. Therefore to achieve this, enterprises conduct a variety of functional tests on software to ensure its quality. Let now try to understand this testing type in more detail with the help of some test cases and examples.

What is functional testing?

It is a black box type of software testing and QA process that helps to validate systems and components against functional requirements. This testing process aims to test the functionality of the application by providing certain inputs and validating the outputs against functional requirements.

Why is functional testing required?

1. Functional testing is required to validate the functionalities of the software
2. This test helps to validate that all the requirements that have been mentioned in the SRS documents have been fulfilled or not
3. This type of testing is more focused on customer requirements whereas non-functional tests are more focused on customer expectations.
4. This test helps to ensure that the product performs well as it claims

What are the different types of functional tests?

1. Unit test — It is the first phase of the software testing process. The main aim of this test is to validate whether the small units of the components are working as expected or not
2. Component test — It is similar to the unit testing method but the only difference is that it is performed by testers and it tests each object of the application separately with or without isolation of other software objects
3. Smoke test — It is also known as build verification testing and it helps to identify whether the build is stable or not and ensures if the build can be used for the further testing process
4. Sanity test — It validates whether the code changes received in the software build are working as expected or not.
5. Integration test- In this test individual module of the application are combined and tested as a group to identify the functionality after combining different modules
6. Regression test — This test helps to ensure that any code change in the software does not affect the existing functionality of the software
7. System test — This test helps to ensure that all the fully integrated software is working well or not
8. User acceptance test — In this test method, the end users/client test the product to ensure that it is meeting all requirements and working as expected. This test helps to gain approval for the release of the product

What are the functional testing test cases and examples?

Let us now look at some of the test cases and examples that will help you to understand this testing type in more detail.

Situation –

Suppose there is an e-commerce app on which the user logs in with their user account and password. The login page has two text fields, one for username and the other for password. It also has two buttons, i.e.; Login and Cancel.

When action is successful, the login page directs the user to the eCommerce app home page. The cancel button cancels the login.

Specifications -

1. The user id field requires a minimum of 6 characters, maximum of 10 characters, numbers(0–9), letters(a-z, A-z), special characters (only underscore, period, hyphen allowed). It cannot be left blank. User id must begin with a number/character. It cannot include special characters.
2. The password field requires a minimum of 6 characters, a maximum of 8 characters, numbers (0–9), letters (a-z, A-Z), all special characters. It cannot be blank.

The use-case scenario above can be tested through a variety of functional tests such as:

1. System tests: This test is performed to ensure that all the components of the software are working as expected or not in perfect combination.

Example — This test would check the customer journey i.e. Ecommerce application loading, entering accurate credentials, directing to the home page, performing tasks, logging out of the system. This test ensures that the workflow proceeds and completes without any errors.

1. Boundary value tests: This test is performed to check how the system behaves when data limits are implemented.

Example — The user-id requires a minimum of 6 characters, this test will check how the system responds when less than 6 characters are entered.

1. Decision-based tests: This tests checks for possible system outcomes when a particular condition is met.

Example -

• If incorrect credentials are entered, the system should alert the user and reload the login page.
• If correct credentials are entered, the system should take the user to the home page.
• If correct credentials are entered but the user wants to cancel login, the system should not direct the user to the home page UI. Instead, it should reload the login page

Conclusion: Today as technology is getting advanced, apps are getting more complex. To ensure that apps work as expected various types of software testing are conducted. One such software testing technique is functional testing that helps to ensure that all the functionalities of the software are working properly. Leverage functional testing from a next-gen QA and software testing services provider to achieve high-quality software products.

About the author: I am a technical content writer and I write articles on various IT-related topics. In this article, I have tried to share my views on functional testing with the help of test cases and examples.