Test Design Techniques: Why You Should Know Them

The end goal of any software development project is the successful delivery of the project to the customer. However, the success of any software project is highly dependent on its quality which translates to compliance with customer requirements and expectations and an absence of defects. 

After all, a system that doesn’t fulfill user requirements is outright useless, and the presence of bugs in the system can not only cost you to lose the trust of your customers but also millions in damage.

According to Statista, an hour of downtime due to a software bug can cost small to medium business enterprises an upward of $300,000, and for large enterprises, it can cost anywhere from $1M to $5M. Furthermore, a report by Ponemon institute states that compromises on system security in 2022 can cost businesses an average of $4.35M per security breach. 

This might amount to just another drop in the ocean for large enterprises, but for many other SMBs, it could mean the difference between success and failure. The existence of bugs in the system could very well cause the production and maintenance costs to exceed the projected cost estimates.

Adopting test design techniques is just as important as marketing your business to new audiences for any new tech business trying to make it in today’s cut-throat market competition.

Here’s an example, just like how you would want to hire an SEO agency like Link Building HQ to increase business exposure on Google SERPs. Similarly, you should hire the best testing resources to ensure your product is free from any errors that may cause stakeholder dissatisfaction.

Importance of Software Testing

As a leading software development firm with ten years of experience in software production, maintenance, and testing, we can affirm that the existence of bugs or defects in a software application can be costly and even disastrous. Plus, removing bugs after development can substantially increase the project cost. Hence, we recommend adopting a software development approach focusing on quality assurance by introducing rigorous test design techniques for fault identification and removal from the system. and more! 

With that said, in this article, we will cover everything you should know about test design techniques – What are test design techniques? Why do we need them? The types and approaches for test design and much more! 

What Is Meant by Test Design?

The testing phase is essential in developing reliable software and improving quality. Software testing verifies and validates whether the product meets customer requirements and expectations. It is necessary to determine the system’s preventative and corrective measures for bug elimination. 

With that in mind, test design is a comprehensive process describing how to conduct software testing. It outlines techniques for determining appropriate test cases based on a systematic enumeration of steps to achieve the specified test conditions. 

A well-thought-out testing procedure makes detecting and eliminating bugs in the software product a lot easier. Furthermore, familiarity with the test design process ensures faster debugging.

The Seven Steps In the Testing Process

Step 1: Test planning

The first phase of the process is test planning, which involves creating a test plan that lays out the project scope, goals, and objectives. A test plan outlines the major activities involved in the testing process. The primary deliverable of this phase is the test plan itself, and the team lead is responsible for drafting the particulars of the test plan.

Step 2: Test monitoring & control

This phase ensures that the progress of the ongoing testing activities keeps up with the activities defined in the test plan. If any discrepancy is found between the test plan and the current outcomes, it’s crucial to employ control activities to rectify the situation and get back on track. 

The main deliverable is a test progress report that helps stakeholders monitor and review the test progress to gauge when the product is ready for release.

Step 3: Test analysis

For test analysis, we look at the deliverables of the software development process, such as user requirements, use case scenarios, and system design, to determine the areas of the system that require testing and define the test scenario. 

Step 4: Test design

The test scenarios defined in the analysis phase are used to derive test cases during the design phase. Writing test cases is more time-consuming than test scenarios due to their comprehensiveness and added level of detail. Defining test scenarios and test cases depends on the nature of the project.

Step 5: Test implementation

When implementing tests, we check to see whether we’re ready to run our tests, and if not, we go back to fix the problem. The most crucial task in this phase is preparing a suitable environment for test execution.

Step 6: Test execution

The test cases and scenarios prepared earlier in the process lifecycle are implemented during test execution in this phase. Whenever problems are discovered, we notify the programmers by drafting defect reports. Once defects in the project are identified, the testers should prepare a defect report and forward the information to the developing team so that they can work to fix the defects.

Step 7: Test completion

At the end of the testing phase, once all bugs have been crushed, it’s time to compile a summary report of the entire testing process and the activities involved. 

Types of Testing Strategies

There are two categories of testing strategies:

1. Static Testing 

Static Testing identifies bugs in the system under test without running the program. It’s carried out early in the development life cycle as early identification of underlying defects can help keep costs down.

2. Dynamic Testing 

The dynamic testing techniques determine how the application responds to dynamic inputs in real time. It tests the system’s dynamic behavior under test by executing the code. The goal is to test the system functionality using dynamic inputs that may or may not be based on user requirements.

What Are Test Design Techniques?

As discussed earlier, test design is essential to the software development life cycle. The test design defines considerations for what should and should not be tested, how to trigger the system, and the intended actions and responses of the system in the face of external stimuli.

Software test design techniques verify and validate the system functionality based on code execution. These techniques are a subset of dynamic testing and include active utilization of the software application to check whether the program works as expected. 

Test design techniques can be classified into three main categories. 

1. Specification-based test design techniques.
2. Structure-based test design techniques.
3. Experience-based test design techniques.

Each technique generally excels at identifying specific types of defects but struggles with others. They help you create improved test cases and streamline testing procedures. Plus, design techniques also increase test coverage with reduced test execution time.

Types of Test Design Techniques

Group #1. Specification-based design technique

This encompasses both functional and non-functional test techniques. This boils down to developing and running tests according to customer requirements, whether functional or not. To that end, it focuses on finding flaws consistent with predetermined requirements. The several kinds of specification-based methods are as follows:

• Equivalence Partitioning

The goal is to segment the given inputs into valid and invalid subsets and then define equivalence between the subsets. After partitioning the input values, you can test any value within a given partition for a test condition, assuming all values within that partition will exhibit the same behavior for a given test. 

This means if a value holds for a test condition, then all values in that partition are held for the same test condition and vice versa.

• Boundary Value Analysis:

This analysis evaluates the boundary values of the specified input values.  It ensures that the program functions as expected when the values at its boundaries are used in test scenarios. The idea is to choose test conditions to test the boundary values. Positive testing occurs when the input value falls within the specified limits, whereas negative testing occurs when the input falls outside the specified limits.   

That is to say, errors are more prevalent in the behavior seen during negative testing than during positive testing. Plus, testing boundary values can reveal more flaws in the system as bugs are more commonplace at boundary ranges.

• Decision Table or Cause-Effect Testing:

Incorporating this method into test design allows testers to understand how diverse input values interact while complying with business requirements. These are useful for evaluating the effect of different input combinations. 

Initially, you’ll need to pinpoint features where the result is contingent on many different inputs.

A Decision Table is a matrix depicting test circumstances against possible responses. The inputs are the conditions in which an action is taken, and the outputs are the results achieved. Make a table for each function that details the various inputs and the corresponding outputs. This technique helps the tester discover system flaws they may have overlooked.

• State Transition Testing:

This technique helps the tester observe how an application undergoing testing responds to a series of test inputs. The system’s response may be recorded while being put through its tests with positive and negative test values. 

You may come across a finite-state system where the same input may have several alternative outcomes.

• Use Case Testing:

A functional testing type where the tester doesn’t need knowledge of programming languages or frameworks. It supports the tester in figuring out which test scripts execute during the duration of a transaction.

Group #2. Structure-based design technique

Structure-based testing methods care more about the structure of the code than its functionality. It’s essential to be familiar with code coverage to comprehend structure-based approaches.

Code Coverage — the process of determining how much of the overall code has been tested using structural testing methodologies — is often performed as part of Component and Integration Testing. 

• Statement Coverage

This method is used to ensure that every code statement present within the program gets executed at least one time. It validates whether the code behaves as intended. However, the false condition is not testable. It is defined as the no. of executed statements / total number of statements x 100

• Conditional Coverage 

This technique covers all Boolean expressions present within the code. It ensures that all bools get validated whether they hold a true or false. It aims to identify that each outcome of every logical condition in a program has been exercised. In this method, each possible combination of true and false for the circumstances around a choice must be examined.

• Decision Coverage or Branch Coverage:

Adequate test cases should be a part of the test coverage requirements to ensure that each test condition covers all potential outcomes for a specific decision at least once. For each input to the program, a relevant function gets invoked. This implies that each decision branch is either labeled true or false.

It is defined as the number of decisions covered/ the total number of decisions.

Group #3. Experience-based technique

These techniques are used to carry out testing procedures by drawing on collective experience. Major factors in this type of assessment are domain expertise and familiarity. These approaches are widespread in user acceptance testing (UAT) and business user testing (BUT). 

These are complementary to other structured methods, such as Specification-based and Structure-based, and they operate on top of other dynamic testing techniques.

• Exploratory Testing:

Domain experts can only execute exploratory testing.  Instead of knowing what features are expected, they undertake testing simply by experimenting with the program functionality and navigating its features. 

The strategies allow testers to learn about the system as they explore it. This kind of testing is excellent for locating critical issues rapidly.

• Error Guessing:

Error guessing is a testing technique that involves making inferences about the defects that could be present in the code. This approach relies significantly on the tester’s prior knowledge and experience, as they use it to make educated guesses about which parts of the testing application could potentially be causing issues.  

As a result, experienced testers are essential for accurate testing. The test should draw on the knowledge gained by vetting other apps with comparable functionality and analyzing previous test data and results as benchmarks. It can be quite effective when combined with other, more organized methods,

Why Do We Need Test Design Techniques?

Test design techniques ensure the satisfaction of all stakeholders involved in the development lifecycle. These techniques allow testers to perform system tests from all aspects to ensure that the customer requirements and expectations are fully met. 

Furthermore, they present two critical benefits for efficient system testing that stem from the uniformity and repeatability of the test cases, which include:

• Reproducing test results

At various stages of testing, testing methodologies are a collection of criteria to assure a minimum degree of consistency, which allows for the possibility of reproducing a test. In fact, if testers had a framework to work off of, they might do their tasks considerably faster, saving a lot of time and energy in the long run.

• Higher probability of defect detection

Bugs are more likely to be discovered when test design approaches are employed as analytic instruments. After all, it’s common to run into issues with element definitions when applying test design techniques to those elements.

Why Should You Prioritize Quality in Development?

Focusing on project quality will save you from developing sub-par software components with hidden bugs and spending unnecessary time on debugging. On the flip side, if you don’t prioritize quality, you’ll end up with low-quality software despite your best testing efforts since you’ll produce low-quality components.

As a result, quality is something that must be thought of from the very beginning of the product lifecycle all the way through to its conclusion. Plus, it’s also quite costly to have delays in quality.

Testing and Quality Assurance with SumatoSoft

We at SumatoSoft, provide full-cycle software development services and every development phase as a separate service. 

70% of our team is senior-level developers and QA engineers who ensure the app complies with domain best practices and our inner quality assurance guidelines. 

Regarding our approach to quality assurance: we start quality assurance by developing a comprehensive QA strategy that depends on the budget, goals, deadlines, and priorities. We only release the software if it meets the specified percentage of acceptance criteria. The percentage is agreed upon with you in the quality assurance strategy. Tested software comes without critical bugs and blockers that can negatively affect further software development and use. Better quality means happier users.

• 10 years of custom software development and QA services
• Our background counts 150+ projects for 11 business domains
• 98% are the percentage of our clients satisfied with the quality assurance services we provide.

We are worth your trust and time. Contact us to get a free consultation on your product. 

Final Thoughts

Shortcomings of the human element in the development cycle can lead to problems for developers, discontent among stakeholders, and negative user experiences. However, rigorous testing can help you deliver quality systems that meet customer requirements and expectations. 

Plus, always design your test cases to maximize the possibility of discovering defects; a poorly designed test will not lead to any positive outcomes. Lastly, suppose you prioritize quality and testing from the get-go. 

In that case, you can save a lot of time and effort in the long run by producing higher-quality components and reducing the time spent troubleshooting and debugging.