Why is Maintainability in Testing important? How to achieve it?

What is Maintainability Testing?

The process of preserving or maintaining a particular state of being is the primary definition of maintenance. Maintainability of the software is handled by developers, who regularly modify the software to satisfy evolving client needs and resolve issues raised by clients. 

Software maintenance for upkeep entails enhancing the software’s capabilities to include new features that clients want, modifying code to avert problems in the future, fixing defects or bugs in the code, and ensuring that no security flaws are present. Additionally, software maintenance often encompasses issuing updates to increase adaptability and effectiveness and replace undesirable features.

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Software maintenance can be greatly impacted by the quality of the software and the code. Software of lower quality requires more maintenance. The effort and cost to add new requirements, or expand upon the existing code, is far higher with low quality software. 

The ability of a developer to keep up with maintenance demands affects the success of the software product. Products that are difficult to maintain quickly fade to obscurity.

The process of software maintenance becomes significantly simpler as maintainability increases. Maintainability testing can assist in making the design of the application more fault tolerant, which in turn means that there will be a greatly reduced need for software maintenance regarding bug fixes; this is only one example to illustrate the need for maintainability testing, many more are illustrated in this guide.

In order to keep customers satisfied and maintain the functionality of the software product carrying out maintainability testing is critical.

Measurement Metrics and Types of Software Maintenance 

Any piece of software can undergo one of four different types of maintenance. These various forms of upkeep each serve particular goals.

1. Corrective maintenance: No matter how extensively tested they are, software products might nevertheless have flaws that manifest without much warning. The amount of time required to locate these errors, and subsequently fix them can be a measure of how maintainable a piece of software is.
2. Perfective maintenance: This type of maintenance concentrates on optimizing the software through improvements. The amount of work required to make these enhancements can be used to gauge how maintainable a software product is. The amount of time and effort taken to introduce new features to the software can be taken and compared against a predefined baseline or perhaps other previously completed projects in order to get an accurate assessment.
3. Adaptive maintenance: In addition to modifications resulting from enhancements, software products frequently require changes as a result of OS updates or updates in other software that the program depends on. Adaptive maintenance consists of adjustments made to keep a software product compatible with evolving environments – such as constantly changing hardware and operating systems. The time and effort required to introduce these changes for better compatibility can be yet another metric to measure how maintainable the software is.
4. Preventative maintenance: This is maintenance performed on the software in an attempt to reduce the potential maintenance that may need to be performed in the future. 

These changes would be made to the software in an effort to preemptively tackle future issues and in order to make the software more tolerant to problems that may come up down the line.

How to Measure the Maintainability of an Application? 

There are several attributes to gauge the maintainability of an application. How changeable an application is, and how stable it is while undergoing changes are two possible measurement scales. It can also be measured based on how easy it is to analyze the application in order to locate errors.

ISO is a well-known internationally adhered standard that provides the guidelines for Systems and Software Quality Requirements and Evaluation(SQuaRE). ISO 25010 defines the following features to measure software quality.

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As illustrated in the chart above there are 5 major ISO-defined attributes to measure an application’s maintainability:

1. Modularity:  This attribute looks at how modular an application is. It assesses whether the software consists of distinct modular components or whether it has non-modular, perhaps interdependent, components where a small change could have a major impact on the rest of the application and lead to further renovations.
2. Reusability: This criterion focuses on whether pre-existing code can be repurposed to offer a similar function elsewhere in the application. Reusing code can reduce expenses, increase productivity, and enhance overall quality.
3. Analyzability: This characteristic gauges how effectively an unintended software flaw can be found and fixed. This parameter can also mean evaluating the effects of implementing a certain change or software upgrade.
4. Modifiability: Modifiability is a criteria that evaluates how much an application can be changed without degrading or compromising the quality of the final product.
5. Testability: The degree to which test criteria can be developed for the application, and whether those aforementioned tests can be run to see if those criteria have been met, is known as testability.

By understanding the various forms of software maintenance and the corresponding attributes to measure the serviceability of an application; Maintainability testing can be performed to accurately cognize the potential of repairing or updating the software successfully and with ease.

How to Carry Out Maintainability Testing?

There is no hard and fast rule to define the process to be followed when implementing maintainability testing. Before and after release, a software application is anticipated to go through a number of updates in order to correct errors, introduce new features, adjust existing functionalities, and alter non-functional software characteristics.

This kind of testing can therefore differ on a case-by-case basis, and the method to implement it can vary as well. However, generally, maintainability testing can be greatly supported and expedited via automated testing tools such as Selenium, or Percy for visual tests.

Maintenance testing can be done using static or dynamic testing approaches. Static testing examines the design documentation and the source code’s organization, structure, complexity, and other characteristics as part of the software development process. 

Some Examples of Static Measures are:

1. The nesting depth for certain control structures such as decision statements
2. Cyclomatic Complexity

Static analysis and reviews are appropriate methodologies for maintainability testing, and they should begin as soon as the design documents are available and continue throughout the process of building the application.  

As it is simpler to identify the causes of problems and rectify them, static testing methodologies can be used early in the software development lifecycle to prevent errors. Maintainability may be assessed early in the software development lifecycle without waiting for a finished and functioning system since it is incorporated into the code and the documentation for each individual code component. 

Dynamic software testing is carried out to examine the code’s dynamic characteristics and determine its functionality. It provides valuable information on the application’s behavior when it is in use. 

Some Examples of Dynamic Measures are:

1. Timing the duration of an update or bug fix.
2. The stability of the system in between changes.

The focus of dynamic maintainability testing is on developing documented maintenance processes for particular applications, such as performing changes to or perhaps improvements upon the software. To confirm that the specified service levels are achievable with the outlined processes, a variety of maintenance situations are employed as test cases. 

This type of testing is especially important when the supporting infrastructure is complicated and there may be several departments or organizations involved in the support procedures.

Maintainability Testing Best Practices

• It is necessary to develop a list of maintainability factors to be considered when carrying out maintainability testing, such as the stability of the system or the complexity of the code.
• Ensure that the software adheres to appropriate standards for the database, interface, and development process. For instance, verifying that the software follows good practices such as optimized algorithms and code reusability. 
• It’s helpful to create a Maintainability Measure to represent the costs and advantages of maintainability for specific factors. For each component evaluated, a form of weighted score can be assigned, allowing for ranking to determine which areas require the greatest attention. This can aid in creating action plans that prioritize tackling the factors with the highest scores first.
• Make sure that the software is compliant with the five maintainability attributes discussed earlier: Modularity, Reusability, Analyzability, Modifiability, and Testability.

BrowserStack allows you to perform automated testing using Selenium. With BrowserStack, you can test on every commit without slowing down releases. This not only helps you catch bugs early but also accelerates release cycles. 

Percy, on the other hand, helps automate visual testing. It helps your testing team capture screenshots, and compare them against each other. It helps teams identify visual bugs in every commit and ship the final product with utmost confidence.

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