In any industry, quality is paramount. This holds true for the software industry too. As global shipments of software rival or even exceed the manufacturing sector by leaps and bounds, Quality Assurance in software is as relevant as it is the manufacturing.
Software testing is defined as an investigation that is conducted to provide key stakeholders in an organization with specific inputs about the quality of the software product or service that is being developed.
Software testing can also provide an independent view of the quality of the software to allow the stakeholders to understand the risks of implementing the software that is being tested.
Software Quality Assurance ensures that the product produced is of acceptable quality and conforms to industry norms.
Software quality and testing can also cause loss of life and property as showcased by the recent example of a software glitch in the Boeing 737 Max aircraft pilot guidance system, which resulted in a plane crash and the irreplaceable loss of hundreds of lives.
In the software industry, Quality Assurance is more commonly known as Software Quality Testing or Software testing. Software testing is the process of ensuring that the software delivered to the customer is of acceptable quality and performs as desired.
Software that has been extensively tested are more stable than untested software and showcase reliability, predictability and use limited resources.
Well-tested software is also not as prone to instability, data theft and data loss. For enterprises, software quality is especially important as many enterprise workflows are completely dependent on the software that they run in.
Software testing methodologies
Software testing can be broadly categorized into two different methodologies – Manual testing and Automated testing.
Manual testing implies testing of software by software test engineers and professionals. They test and verify various aspects of the software according to test cases and test plans. Many software requires to be tested by test engineers for many changes for which automation test scripts cannot be created easily.
Typical examples are color rendition, user experience and design. Manual testing is relatively low-cost compared to automation testing but is labor intensive and subject to human error and bias.
Automation testing is the creation of automated test scripts that allow software to be tested without human intervention. Repetitive, labor intensive tasks like data input validation and unit tests can easily be automated by test engineers to ensure that these are run every time a new change is made to the software code without requiring the assignment of an engineer to test that change.
Automation testing requires specialized teams that are adept at creating test scripts according to the automation testing suites used by their organization. Their requirement of specialized software and teams make automation testing costlier to implement.
Automation testing typically pays off in the long run as automation scripts written by specialist testers typically manage to uncover a much higher number of bugs compared to manual testing.
Software vendors adopt need-based testing methodologies and use a combination of manual and automation test strategies to ensure that the software they publish is error free.
Software Testing Techniques
Software testing techniques can be divided into three categories:
Black Box Testing – Black box testing is testing the software by emulating the end user. This testing technique assumes that the tester is the end user of the application and tests the interface without being concerned about the internals of the software that is being tested.
White Box Testing – White Box testing is testing the software at the structural level, verifying the internal workings of the software and the integration of various components of the software. White box testing can be applied at the unit, integration and the system levels of software testing processes.
White box testing techniques include the following:
API testing: Testing of the software by utilizing public and private programming interfaces.
Code Coverage: Testing the software to ensure that all statements in the program are run at least once.
Fault Injection: Introducing faults intentionally to test the robustness of the software
Mutation testing: Altering the source code to find and remove redundancies. This can include testing values (constants), decisions (relational and logical operators) and statements (editing code to check if code has been copied).
Dynamic testing: Executing the source code of the software to ensure that the response to variables is consistent.
Static Testing: Testing the source code and its accompanying documentation without executing the code.
Grey Box Testing: Grey box involves performing black box testing while having access to the source code of the software to ensure that informed tests can be run to determine boundary values and errors. Grey box testing implements intelligent test scenarios that are based on the access to both source code and the user interface.
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Types of testing
Software testing can be divided into many types. Each type has its own need, requirements, advantages and disadvantages. Software testing is primarily divided into functional and non-functional types.
Functional tests are run to ensure that the software under test conforms to the software requirement specification.
Functional testing types include:
Unit testing involves testing independent modules of the software. This test is usually run by programmers to test the code that has just been compiled.
Testing all modules of the software to ensure that they work in conjunction with each other. This testing technique is especially important in distributed systems.
Testing the entire system as per the software requirements.
Sanity testing tests if the planned functionality is working as expected
Smoke testing checks if the software is ready to be tested thoroughly.
Interface Testing determines if two different components of the software are able to communicate with each other.
Regression testing is testing the application as a whole to test a new change in functionality.
Acceptance or User Acceptance testing involves testing the software against its requirements to test if the end to end flow is as per the needs of the user.
Non-Functional testing involves testing the non-functional requirements of software to determine its performance, usability, and reliability.
Non-functional testing types include:
Performance testing is done to check if the software performs up to set standards and performance requirements.
Load testing is done to check the behavior of the software under specific load conditions that might cause performance degradation.
Stress testing involves testing the application to figure out the breaking point of the application.
Volume Testing involves testing the performance and processing speed of the system with an unusually large data set or high volume.
Security testing involves testing the data in the software against intrusions, malware attacks and exposing any loopholes in the security of the software.
Testing a software under diverse system configurations.
Testing the installation/uninstallation process of the software.
Recovery Testing involves pushing the system to crash and testing its capability to recover from such situations.
Reliability testing involves testing whether the software can perform a failure-free operation for a specified period in a specified environment.
Usability testing involves testing if the software can easily be understood by the end user.
Compliance testing involves testing the software according to set norms to check if the software adheres to those norms.
Localization testing involves testing the multi-lingual ability of the software.
Software testing levels
Levels in software testing are the different stages of the software development lifecycle where testing can be conducted and implemented. Bringing your software to test early on in the software development lifecycle can ensure that your product performs better as it will be well tested.
Software testing levels include:
Unit testing involves testing the smallest testable portion of a software which can be compiled, linked, loaded and tested individually. This test is performed by developers to ensure that each part of the software performs as intended.
Integration testing involves testing the flow of data from one component of the system to another. This test checks if various modules of the software perform as intended when tested as a group. This test level also validates if the software is ready for system testing.
This testing level involves testing the entire system to see if it behaves as intended and meets the requirement specification.
Acceptance testing involves testing the software against delivery specification of the system to ensure that everything works as intended for the end user.
Building a software testing strategy
According to Wikipedia, a test strategy is an outline that describes the testing approach of the software development cycle. It is created to inform project managers, testers, and developers about some key issues of the testing process.
This includes the testing objective, methods of testing new functions, total time and resources required for the project, and the testing environment. As it is with any other aspect of a business, software testing also involves following a set strategy to ensure that business and product goals are met.
Factors that a business must consider while choosing a software testing strategy:
As risk is considered paramount during testing, therefore it is important to consider the various risks and their levels. For a mature app, regression is a critical risk that must be considered. For a new app, a risk-based strategy can expose many problems at the outset.
For a testing strategy to succeed, it must meet the needs of the stakeholders. If, for example, uncovering the maximum number of bugs prior to release is important, a dynamic testing strategy would make more sense compared to a static testing strategy.
No two individuals are equal. Taking that into consideration for test teams is a wise thing to do. A standard compliance strategy is a good option when your testing team has varied skill levels.
Many contract-based software have standardized requirements that leave little or no margin for change. For such situations, an analytical software testing methodology that uses the requirement specification as a yardstick is apt.
When a legacy system is being refactored or entirely reengineered, business requirements call for using a model-based strategy that can leverage existing knowledge to create an effective test strategy.
In some cases, compliance is mandatory for a software to be used by the end user. In such cases, methodical strategies can be used to ensure that compliance needs are considered and met.
There is no hard set rule towards choosing a software testing strategy, however, the strategy chosen should according to the needs and the requirements of the project and the organization as a whole.
A robust software testing strategy ensures that testing is performed at all technology stack levels to ensure that the system works well as a whole.
Some points to consider for testing strategies include:
If testing leaves no time for fixing issues, it defeats the whole purpose of testing the software. Test plans should leave time for both fixing and retesting to ensure that defects can be addressed in the same release that they are tested in.
Leaving testing for the last moment can cause unnecessary delays or force the QA team to release a buggy build in the market.
Allowing teams to take ownership of the defects uncovered during the testing process helps developers to understand the reason for the testing process and for the testers to take ownership and drive the product to success rather than passing the buck and trying to blame issues on the other team.
Scripted tests limit the number of bugs that can be uncovered. Any tests that can easily be scripted must be automated. Manual testing should be limited to testing the system using creativity and exploration to try and uncover as many bugs as possible.
Documentation and reportage
A well-documented software requirements specification allows testers to test better. A well-documented bug report can do the same for developers by ensuring that less time is spent in communicating back and forth just to gather basic information about the bug that has been logged.
Testing software as frequently as possible ensures that both development and test teams stay motivated and end up with a much smaller kitty of bugs to address at the last moment. This also helps in controlling the product backlog.