What is Software Testing?

“To err is human, but to really foul things up you need a computer.”

Paul Ehrlich, US biologist

The world relies on software. Without it, our supermarket shelves would be empty, our holiday flight would never take off and our work to-do list would remain unticked.

With it, we can shop to our heart’s content, fly to far-flung corners of the earth and achieve ever-more in our careers.

But only if it’s functioning properly.

And that’s why the importance of software testing should never be underestimated.


  1. What Is Software Testing?
  2. Why Is It Important?
  3. When Should The Testing Process Start?
  4. When Should Testing Stop?
  5. What Methods of Testing Are There?
  6. What Types of Testing Are There?
    1. Functional Testing
    2. Non-Functional Testing
  7. Who Can Test Your Software?

What Is Software Testing?

testing01Software testing is a process that assesses and evaluates the functionality of a piece of software. It uncovers whether it meets its specific requirements and delivers what it promises to deliver.

Carried out by dedicated testers with a broad range of skills, the ultimate aim is to identify errors and ensure the application is defect-free.

While it’s impossible to guarantee this 100%, testers who thoroughly explore, investigate and mitigate allow quality software to be sent out into the world with confidence.

Why Is It Important?

Glitches, bugs, errors: each one can cause problems ranging from the inconvenient to the tragic.

At one end of the software disaster scale, your business could fall victim to a software malfunction that holds your order-processing system to ransom. You’re left with a technical headache, disgruntled customers and compromised profit.

At the other, an unidentified issue can lead to loss of life. When a China Airlines Airbus A300 crashed due to a software bug in 1994, 264 people died.

Whether the possible outcome is expensive or dangerous, the testing process can minimise risk, improve quality and reduce business costs.

When Should The Testing Process Start?

Ideally, as early as possible. Once software has been developed, getting it market-ready quickly should be a priority.

Adopting an agile approach helps here. Testing early and often, embracing a “push left” attitude, gets actionable results sooner.

This early engagement between all stakeholders triggers knowledge and understanding right at the start of a project, saving both time and money. You can then react quickly to market demand and fast-track new development opportunities.

When Should Testing Stop?

In theory, testing should never end. Like painting the Forth Bridge, it needs constant attention and investment.

Once a decision has been made to launch, initially-tested software benefits from ongoing test support, defect and environment management and continued regression and release testing. If its capabilities are further developed, this is even more crucial to guarantee business as usual.

What Methods of Testing Are There?

Manual Testing

Manual testing doesn’t rely on any form of automated tool or script. Testers assume the role of end-user and study the application for any elements that don’t meet fundamental requirements.

Using an agreed strategy, testers carry out their work in distinct phases to identify unexpected behaviours and bugs.

This approach requires a high level of physical time and effort as the tester has the responsibility to check and record all of their detailed work.

Automation Testing

Test automation uses specialist software to oversee the execution of tests, comparing actual outcomes with predicted ones.

It’s especially suited to large projects that require repeated testing and software that’s already been proved stable via manual testing.

More efficient and quicker than traditional methods, it automates repetitive tasks and performs additional tests that are difficult to do manually. Automation creates more time within a project lifecycle, expanding the scope of a test strategy and delivering more accurate results.

What Types of Testing Are There?

There are dozens of different kinds of testing.  A test strategy can be built around selecting the most relevant types to meet the unique criteria of the project.

They can all be split into two groups: functional and non-functional.

Functional testing, which is completed first, focuses on checking that all functions meet the documented business requirements of the software. This is carried out by providing appropriate input, verifying the output and comparing the two with the expected results.

The software’s action, such as the log-in process or use of APIs, can then be validated.

Examples of functional testing, which is aimed at meeting users’ requirements, include:

  • Integration testing: checking that all files are able to travel smoothly through all systems
  • User acceptance testing (UAT): business-focused testing of all functionality and user interactions
  • Regression testing: testing previously-tested functionality to ensure newly-delivered software has not had an adverse impact
  • Unit testing: testing certain functions within individual units of code
  • Smoke testing: preliminary testing to spot basic failures that would compromise further work

Non-functional testing is carried out to check the performance, load and security of an application. Its usability and reliability are put to the test to assess its readiness for release.

Testers will analyse how the product actually works, e.g. how long it takes to log in, how many users can simultaneously access the software etc.

Examples of non-functional testing, which is aimed at meeting users’ expectations, include:

  • End-to-end testing: testing full end-to-end business processes to ensure integration across all systems
  • Performance testing: checking if software will perform well during its expected workload, focusing on resource usage, reliability and scalability
  • Load testing: a form of performance testing undertaken when multiple users log on so it can be assessed under real-life conditions
  • Migration testing: streamlining data migration and ensuring consistency between legacy and new databases
  • Stress testing: testing an application beyond the usual limits of its operation
  • Cutover testing: testing the cutover and roll-back processes, plus system set-up to ensure a smooth go-live

Who Can Test Your Software?

If you don’t have the in-house resource to test your chosen software, experienced test consultants can join you to develop a test strategy based on your unique requirements.

Combining the different test phases relevant to your project, they can provide the crucial critical thinking, creativity and attention to detail that it demands.

They’ll spot the stumbling blocks, eradicate the errors and banish the bugs to give you streamlined software that exceeds your expectations.