Functional Testing Vs Performance Testing

Discover the differences between Functional Testing and Performance Testing in this article. We will assess the possibility of doing both at once. Let’s begin.

The differences between Performance Testing, Load Testing, and Stress Testing were explained in detail with examples in our last tutorial.

Software Testing covers a wide range of areas where verification or validation of software functionality can occur. Occasionally, non-functional aspects become less concerning than the functional aspects. They are not performed practically; simultaneously during software testing.

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Functional Testing & Performance Testing

This article explains the added benefits of the quality of the software product during various scenarios in the software testing life-cycle when both functional and non-functional are taken simultaneously.  

Quick Difference Between Performance Testing and Functional Testing

Combining Functional and Performance Testing: Benefits

Functional testing becomes much more important for any pre-release software. Actual results-based verification and validation in a replicated production or test environment is where the testing usually happens.

Defect leakage can be one of the greatest issues

Testers have more responsibility compared to developers in terms of the quality of the product. They don’t want the tested product to have defect leakage. Testers only perform functional testing to achieve this.

The following is a conversation between a Test Manager and a Tester:

Here are a few questions from the above conversation to be considered:

• Does functional testing have a dependent factor in performance?
• What if the performance of the software is degraded, but the delivery of the product happens without checking the performance?
• Performance testing–is it co-existing within the functional testing process?

Testers rarely work on the non-functional aspects unless they are requested to do so. It’s common to avoid non-functional testing until the client has reported issues with the performance of the software under test.

So, here are 2 questions for you to consider:

1. Does performance affect functional testing?
2. Should we retain performance testing as a standalone deliverable, despite client worries?

Performance testing is crucial!

The software works according to various architectures and the following models, which include:

1. Required response reply models
2. Transactions based systems
3. Load-based systems
4. Data replication-based systems

The above-mentioned systematic model’s functional testing behavior depends on the performance of the system.

The automation point-of-view requires much attention towards performance testing.

The following is a conversation between a client and the Test Manager.

(Client is referred to as ‘CL’ and Test manager as ‘TM’)

Case Study

Company ABC is working on a project for developing Software A. Testing of Software A is being done by the company XYZ.

The contract for Company ABC and XYZ has some restrictions for their collaboration. Any discussion between the 2 companies should happen once a week or three times a month. The system works on the model of the request-response mode. Company ABC has completed the development phase.

Now it’s the time for Company XYZ to perform the formal functional testing on Software A. XYZ works on testing Software A. They have given a clean chit on the software and have given the ‘Go’ for live implementation after 2 cycles of testing.

Despite the quality certificate from the testing team, the live implementation did not go well. There were lots of post-production bugs. There were many issues faced by the clients, including a break in functionality for the end-to-end business processes.

So now what is the problem?

• Is it a problem with a restriction on collaboration between the development and testing teams?
• Were the requirements not captured 100%?
• Was the product not tested in a proper test environment?
• Or are there any other causes?

After conducting careful research and analysis, we inferred the following:

1. There were a few of the dependent and interdependent applications that had performance issues while fetching the responses.
2. The test inputs used were not absolute.
3. They did not take care of the robustness of the software.
4. Lots of sync issues between the multiple independent applications.
5. The software testing had done multiple re-works which were not considered.

Hence, after the remedial actions planning team stepped in, they came up with the following suggestions:

1. The interaction between the development team and the testing team has to be increased.
2. All dependent applications need to be connected and included in the system’s functional testing.
3. The request and response time-out value needs to be increased to give room to non-production environments.
4. Various inputs ranging between simple and complex have to be used in functional testing.
5. The remedial team advises that non-functional testing, especially performance and load testing, must be done.
6. In addition to system testing, system integration testing has to be performed.
7. A minimal time gap between any two testing iterations has to be provided. This is for re-testing the previously identified bugs.
8. All bugs identified in previous iterations should be fixed in the current iteration.

The testing team implemented all the proposed actions and there were a huge number of defects uncovered in little time.

Observations:

1. The live implementation schedule of the software has improved significantly by optimizing the test-cycle times.
2. There has been good progress in the optimization of software quality. Hence, there was a tremendous decrease in the number of support tickets post-implementation.
3. Re-works were decreased, and it was testing iterations instead of re-work. Between the different iterations, there were better improvements in the quality observed.

Conclusion

Performing non-functional testing during functional test execution is more advantageous and will add more benefits to the overall software quality. This will identify performance bugs (restricted to the testing environment and dependency) and hence will reduce situations of functional issue assumptions.

Sufficient planning for performing functional and non-functional testing (to a minimum level) has to be done to keep a strong relationship among the other stakeholders of the project.

About Author: This is an article written by Nagarajan. He is working as a test lead with over 6 years of testing experience in various functional areas like Banking, Airlines, and Telecom in terms of both manual and automation.

Our upcoming tutorial will explain more about the Performance Test Plan and Test Strategy. Please post your feedback and queries about these tutorials in the comments section below. We would love to hear from you.

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