Applying Metamorphic Testing in Machine Learning Applications

Feb 17, 2023, 11:25 AM EST
4 mins read
Applying Metamorphic Testing in Machine Learning Applications

Metamorphic testing is a software testing technique that evaluates a system’s behavior by observing changes in its outputs when a series of transformations are applied to its inputs. The method has recently gained popularity due to its ability to uncover system defects that traditional testing methods may miss. In the context of machine learning applications, metamorphic testing can be used to validate the robustness and reliability of machine learning models and algorithms. Metamorphic testing can be applied in the following ways.

Identifying the Limitations and Weaknesses of Machine Learning Models

Metamorphic testing can uncover scenarios where the model produces incorrect results or fails to produce results altogether. This information can improve the model’s performance and reduce the risk of deploying a faulty model into a production environment.

Evaluating the Robustness of Machine Learning Algorithms

Metamorphic testing can test how a machine learning model responds to changes in its inputs, such as adding or removing features, using different algorithms, or variations in the data distribution. Testing provides valuable insights into the strengths and weaknesses of different algorithms and helps organizations choose the best algorithm for their specific needs.


Helping Organizations save Time and Money by Reducing the Need for Manual Testing

Organizations can automate the testing process instead of manually testing each scenario, reducing the risk of human error and freeing up resources for more critical tasks.

Getting external Experts for the Testing Job

From a business perspective, metamorphic testing is essential for organizations that want to invite more advanced personnel from another organization to machine-learning models and algorithms. This act of software testing outsourcing technique helps identify and fix problems with their models before they become significant issues, reducing the risk of costly and time-consuming production failures. Moreover, it helps organizations improve the quality and performance of their models, making them more attractive to customers and increasing their competitiveness in the market.


Metamorphic Testing Steps

The following are the steps to apply metamorphic testing in machine learning applications:

Identify metamorphic relations

The first step is to identify metamorphic ties, which are the relationships between the inputs and outputs of the system under test. These relationships can be based on the mathematical properties of the system or the domain knowledge.

Design test cases

Test cases can be designed based on the metamorphic relations identified in step 1 (Identify metamorphic relations). These test cases are variations of the input data that should result in a consistent output, even if the input has changed.


Execute tests

The test cases designed in step 2 (Design test cases) are then executed on the machine learning model. The model outputs are compared with the expected outcomes to determine if the model is functioning correctly.

Analyze results

The results of the tests are analyzed to determine if the model is functioning as expected. If there are discrepancies between the expected and actual results, further investigation is needed to determine the root cause of the problem.

Metamorphic testing can be an effective technique for improving the robustness and reliability of machine learning models. It can help to identify bugs and anomalies in the model that you may not discover through traditional testing techniques. Additionally, it can help validate the model’s consistency even when input data changes, which is crucial in real-world machine-learning applications.



By using metamorphic testing, organizations can develop and deploy machine learning models with greater confidence, knowing they have been thoroughly tested and validated.

The opinions expressed here by our contributors are their own, not those of GadgetBond.

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