Coding, Software Development

What is Software Testing in Software Engineering?

Written by John Terra
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Updated on September 12, 2024

Every day, more apps and software are released to the public, eager for more functional, high-quality, reliable software. Note the word “reliable.” A company can release an app with superb graphics, tons of bells and whistles, and an excellent user interface, but if it’s bug-ridden and crashes often, it’s useless. Enter software testing.

This article discusses software testing, answering the question, “What is software testing in engineering?” It covers its importance, its importance, the different types and levels, and strategies and best practices. It also shows how online training in software development can help you boost your career in the field.

But before we thoroughly explore software testing in software engineering, let’s define the term.

What is Software Testing?

So, what is software testing? Software testing is a process that checks, verifies, and validates whether the software product meets the expected requirements and ensures that the application is bug and defect-free. Testing involves executing software and system components using manual and automated tools designed to evaluate one or more appropriate properties, looking for measures that can be taken to improve the software’s accuracy, efficiency, and utility.

Software testing is a tool used to run the software through its paces before release, ensuring it does what it’s supposed to and is free of flaws.

The Importance of Software Testing

A writer doesn’t send off their work without first proofreading it. The Navy doesn’t place a newly constructed warship into service without giving it a shakedown cruise. Similarly, developers can’t release app after app without testing it to ensure it fulfills the designer’s intentions, works properly, and isn’t riddled with errors.

Improperly tested software invariably contains many errors and bugs, requiring the company to institute potentially costly and time-consuming measures to address the problems. Meanwhile, users become irritated with the poor quality of the release, giving the product and, in many cases, even the company itself a bad reputation. This bad reputation could negatively impact software sales and drive the company out of business.

So yes, software testing is essential.

The Need for Software Testing in Engineering

Software bugs cost money and can even lead to loss of life, and this will continue to be a problem. For instance:

In 1994, a China Airlines Airbus A300 crashed because of a software bug, killing 264 people.
In 1985, a software bug caused Canada’s Therac-25 radiation therapy machine to malfunction, delivering lethal radiation doses to patients that left three people dead and critically injuring three others.
In 1999, a software bug caused a $1.2 billion military satellite launch to fail, resulting in the costliest accident in history.
In 2014, Nissan recalled over 1 million cars because of a software failure in the airbag sensory detectors.
In 2015, Starbucks closed approximately 60 percent of its U.S. and Canadian stores due to a software failure in its POS system.

How Does Software Testing Work?

Software testing typically breaks down into two main steps:

Verification. Verification answers the question, “Are we building the product correctly?” It describes a set of tasks that ensure the application correctly implements a specific function.
Validation. Validation answers the question, “Are we building the right product?”. It refers to tasks guaranteeing that the software conforms to customer requirements.

Now, let’s explore some specific kinds of software testing. Remember, there is no universal, definitive standard for classifying software testing. Consequently, depending on your source, you could encounter radically different breakdowns of software testing classification. This article presents a breakdown of software levels and testing that tries to organize them logically and easily.

The Levels of Software Testing

Software testing can be split into four key levels:

Unit Testing. Unit testing tests individual units and components of a software or system. Unit testing aims to validate that each software component or unit performs as designed.
Integration Testing. Integration testing involves combining individual units and testing them as a group. Integration testing aims to uncover faults in the interactions between integrated units.
System Testing. System testing tests a complete, integrated system or software application. System testing aims to evaluate how the system complies with the specified requirements.
Acceptance Testing. Acceptance testing evaluates the system’s compliance with the business requirements and determines whether the product is acceptable for delivery.

Types Of Software Testing

We can divide software testing into three broad types and then divide each type into sub-groups.

Functional Testing. Functional testing validates the software system against its functional requirements and is performed to check whether the application is working as the software’s functional requirements dictate. Sub-types of functional testing include Integration testing, System testing, Smoke testing, and Unit testing.
Non-functional Testing. Non-functional testing checks the application for non-functional requirements such as performance, portability, scalability, and stress. Different types of non-functional testing include Performance testing, Stress testing, Usability Testing, etc.
Maintenance Testing. Maintenance testing modifies and updates the software to meet the customer’s needs. Maintenance testing involves regression testing, which verifies that recent code changes haven’t adversely affected the other parts of the software that have thus far worked fine.

We can add the following two testing methods as further ways of breaking down the three primary types:

Manual Testing. This testing type tests software manually without using any automation tool or script. The tester assumes the end-user role and tests the software for unexpected behaviors or bugs. Testers ensure testing completeness using test cases, plans, or scenarios. Manual testing incorporates unit, system, user acceptance, and integration testing stages. In addition, manual testing also includes exploratory testing, where testers explore the software to find errors.
Automation Testing: Automation testing, also called test automation, has the tester writing scripts and using other software applications to test the product. This process involves automating a manual process. Automation testing re-runs manual test scenarios quickly and repeatedly. Aside from regression testing, automation testing also tests the application from a performance, load, and stress point of view. The automation process increases overall test coverage, improves testing accuracy, and saves the organization time and money compared to manual testing.

Software Testing Techniques

There are three recognized testing techniques:

Black Box Testing. The tester lacks access to the software’s source code in this testing technique. It is conducted at the software interface, heedless of the software’s internal logical structure.
White Box Testing. In white box testing, the tester is aware of the product’s internal workings, has access to the source code, and is performed by ensuring that all internal operations are conducted according to the specifications.
Grey Box Testing. This technique is testing where the testers should have some knowledge of the implementation.

Software Testing Best Practices

Here are the commonly accepted best practices of software testing:

Test continuously. Project teams test each build upon availability, thus enabling the software to be validated in real environments sooner in the development cycle. This practice reduces risks and improves the software’s functionality and design.
Involve the users. Software developers must involve users and encourage open-ended questions about the application’s required functionality. This practice helps the team to develop and test the application from the customer’s perspective.
Break tests into smaller parts. Dividing the tests into smaller fractions saves time and other resources, particularly in environments that require frequent testing. This practice also helps teams analyze tests and test results better.
Use metrics and reporting. Reporting lets the team members share goals and test their results. Advanced testing tools integrate the project metrics and offer an integrated report in the dashboard that team members can easily review to check the project’s overall health.
Don’t skip regression testing. Regression testing is one of the most vital steps in the testing process since it encourages application validation.
Programmers shouldn’t write tests. Programmers could be biased towards their apps and coding, so it’s best to avoid having them create test cases.
Incorporate service virtualization. Service virtualization simulates undeveloped or missing systems and services. This lets teams reduce dependency and begin testing sooner. Teams can then modify and reuse the configuration to test different scenarios without changing the original environment.

What Are the Benefits of Software Testing in Software Engineering?

Software testing is clearly a good idea, but what are its specific advantages? Software testing’s primary benefits include:

Customer satisfaction. If people don’t buy your software, it will be a commercial flop, regardless of how awesome it is. Software testing detects errors and vulnerabilities early in the development phase so problems can be remedied before delivering the product to the public. Additionally, usability testing checks the application for the customer’s ease of use.
Cost-effectiveness. Timely testing helps save money and time in the long run. If problems are caught and addressed in the early testing phases, fixing them costs less.
Product quality. Software testing guarantees a high-quality product, as errors and bugs are discovered and addressed early in the development cycle.
Scalability. Non-functional testing can identify scalability issues and show where an application might stop working.
Security. Security is a big concern today. Security testing focuses on testing the application for security gaps and vulnerabilities from any internal or external sources.

You may notice that these benefits overlap to some extent.

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