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Testability in Software Testing

January 9, 2023

Testability refers to the extent of how easy or challenging it is to test a system or software artifact. It is often measured by how many tests can execute on a given system.

Software teams need full knowledge about software testing, what it does, and how it behaves. This understanding includes the behaviors and functionalities the software product should have to perform correctly. The more complex the system, the harder it is for testers to understand its behavior and thus find bugs or errors in the software.

As mentioned earlier, testability refers to the degree to which every module, requirement, subsystem, or software component of your architecture can be confirmed as satisfactory or not. In simple terms, the testability of the software artifacts can be a unit of source code, a design document, a test plan, a test procedure, or a system under test. 

In this article, we will look into what actually is software testability, its importance and requirements in the industry, and how the work gets done.

Testability Significance

Software testing is necessary to determine if the product meets the customer’s needs and expectations. Software testing can be either manual or automated. Test automation is done by a software product that checks for errors, software bugs, or potential risks in the code.

Testability is one of the main aspects of software testing. Testability has two major dimensions: Test coverage and test reliability. 

Test coverage refers to the number of parts that are tested in the product, while test reliability refers to how often tests are executed with a high degree of quality.

Software Testing is essential for any project in order to ensure that it meets customer expectations and standards.

Main Factors of Software Testability

Software testing is the process of executing a program with the expectation of finding errors. It is an essential part of the software development process.

Read more: The ultimate guide to Software Testing 

Software Testability is determined by how easily and effectively a product can be tested by its developers, operators, and users.

The main factors that determine better software testability are

The complexity of the software

The ability to test functionality means that a component or application may be tested using techniques such as test-driven development or table-driven testing. To get better software testability the components should be designed to be decoupled, modular, and stable. Stubs or mocks are effective paths to achieve isolation.

The size of the entire team developing it

The testing team members who may handle this operation can have 8-12 members for the workload.

The size of the development system

The development of large software systems is a challenging and demanding task, and software testability is a problem in these systems. The cost of testing and reworking to ensure that systems are sufficiently reliable has made it very important to reduce the time and effort needed to test software. 

The number of stakeholders involved in defining requirements for it

In a software development process, the stakeholders come with different perspectives and concerns who participate and define the requirements. These stakeholders include the customer, business analysts, software engineers, and test engineers.

Additional Testability Factors

The following are some factors that must be taken into account when testing software:

  • The number of modules and software components.
  • The degree to which the software is going to test in isolation.
  • Time it will take to test the software.
  • The importance of testing the software for a given use case or scenario.
  • Whether there is an existing test plan for the software.

Software Testability Requirements

The higher the testability, the easier it is to find bugs in the system.

Module Capabilities

Module capabilities for software testability is a topic that has been discussed extensively in the past days. It is a great way to ensure that software modules are tested thoroughly and the testing activities are more efficient.

The module capabilities for software testability include:

  • The ability of the module to be tested by itself.
  • The ability of the module to be tested with other modules.
  • The ability of the module to be tested with external entities such as hardware or other software modules.
  • The ability of the module to be tested with its own data.

Observation Capabilities

The process of running a program or application with the goal of identifying errors is known as software testing. Testing methods involve Static analysis, dynamic analysis, and functional analysis.

Static Analysis: 

Static analysis is a type of software testing that analyzes the code without actually running it. It is more like code inspection and is performed by programmers. It can find common errors that include coding logic issues, security vulnerabilities, and other defects in the code.

Dynamic Analysis: 

Dynamic analysis is a type of software testing that executes the program or application while monitoring its execution with one or more tools in order to detect errors that can’t be detected through static analysis alone. It can also find performance-related issues like bottlenecks and deadlocks.

Functional Analysis: 

Functional analysis tests how well an application performs its intended function by executing it with various inputs and examining how it responds to each of the inputs provided.

Testing Support Capabilities

Testing can be done either by manual testing or automation testing means, with the former being more common in smaller organizations and the latter being more common in large ones.

Testing support capabilities improve software testability, which is a requirement for any organization that wants to reduce development costs and increase its speed of delivery. It helps them find out what needs to be improved before they start developing their product.

Defects Disclosure Capabilities

The following is a list of some defects that software testers should be aware of and be able to detect during the testability phase:

  • Defects in code that can lead to crashes or other failures.
  • Defects in code that can lead to security vulnerabilities.
  • Defects in code that can lead to performance problems.
  • Defects in code that can lead to data corruption or data loss.
  • Defects in code that can lead to denial of service (DoS) attacks.
  • Defects in code that can lead to information disclosure (privacy) violations.

Software Testability Measurements 

Testability is a measure of how easy it is to test software. It is an essential factor in determining the quality and reliability of the software.

There are many different paths to measure the testability of the software. One way is through metrics such as code coverage, lines of code, or cyclomatic complexity.

Another way to measure software testability is by looking at the ease with which one can write tests. In this case, it can measure four different components:

  • The number of lines of code that need to run in order to execute a given test.
  • The number of lines of code that need to execute in order to set up a given test.
  • The number of lines of code that need to execute in order for a number of test cases to fail.
  • Time it takes for the programmers to know what needs testing and what doesn’t.

How to Increase Testability

There are many ways to increase the testability of your code. Below are some tips

  • Use a unit testing framework: A unit test framework provides a set of tools and conventions that make it easy to write and run tests. By using a unit test framework, you can more easily write and maintain tests. QA Touch is one of the finest test case management tools that help QA teams to develop a quality project on time.
  • Write small, focused modules: Smaller modules are easier to test in isolation. Tightly coupled modules are only possible to test one module without affecting the others.
  • Use dependency injection: Dependency injection is a technique for decoupling modules. By injecting dependencies into modules, you can more easily test them in isolation.
  • Write self-contained tests: Self-contained tests are easier to set up and run. They don’t rely on external resources they can be run anywhere and at any time.
  • Use mock objects: Mock objects are simulated versions of real objects. During tests, they can act as a stand-in for real objects. This enables you to test the behavior of your code without depending on the mock object’s actual implementation.

Key Benefits of Software Testability

There are many benefits to software testability, but some of the key benefits include:

  • Increased Quality: By making your software more testable, you can increase the overall quality of your software. It is because testability leads to better design and fewer software bugs.
  • Faster Testing: When your software is more testable, you can test it faster. It means you can get feedback on your software sooner and iterate more quickly.
  • Reduced Costs: By making your software more testable, you can reduce the costs associated with testing because testing is typically faster and effortless when the code is more testable.
  • Better Understanding of Requirements: When your software is more testable, it can help you to understand the requirements for your software. It is because you can test different parts of the code to see how they work together.
  • Greater Flexibility: When your software is more testable, it provides greater flexibility. It means that you can change the code without breaking existing tests. Additionally, you can add new tests as needed to cover the new functionality.

Software Testability — Final Points

Testability is a critical success factor for any software development team. Having the knowledge of the factors that impact testability, and taking steps to address them early in the development process can help software companies improve the overall quality of their software products and avoid many of the problems associated with testing activities.


What is software testability? 

Software testability is a measure of how easy it is to test a software system or component. Testability can be affected by factors for example structure of the code, the size and complexity of the system, and the tools and techniques available.

Why is software testability important? 

Software testability is essential for quality assurance because it can significantly impact the availability, cost, and effectiveness of testing. If a system is difficult to test, it may require more time and resources to achieve adequate coverage. Additionally, defects may be more expensive to fix if they are found late in the development process, they may be more expensive to fix. 

How can I improve the testability of my software? 

There are many ways to improve the testability of your software. Some common approaches include refactoring code to improve readability and modularity, using design patterns to simplify the test process, and providing adequate documentation. Additionally, automated testing tools can help to speed up the testing process and reduce costs.

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