A guide to acceptance testing

During software development, engineers may not always perfectly grasp the client's needs, despite following technical specifications to deliver a quality product. While undergoing testing phases like unit testing, integration testing, and system testing, minor errors may remain undetected until the system is utilized by end-users in real scenarios. This is where acceptance testing becomes crucial.

Acceptance testing constitutes a software testing approach aimed at verifying system compliance with business requirements. It assesses whether the software aligns with specified requirements and user expectations, serving as the final phase of testing preceding the system's release to end-users. Hence, it's often referred to as end-user testing and is conducted in an environment closely resembling production.

The primary goal of acceptance testing is to ensure that the product functions as intended and meets requisite criteria and specifications. Typically, acceptance tests yield binary outcomes — pass or fail.

In this article, we'll discuss acceptance testing, explaining its objectives, types, and application scenarios, along with its advantages and limitations.

Table of contents:

Purpose of acceptance testing

The main purpose of acceptance testing is to verify that the software meets all functional and non-functional requirements, standards, and expectations, ensuring that:

The software meets the project requirements and user expectations
All defects and bugs have been eliminated, which improves the overall quality and reliability of the software

Acceptance testing involves the interaction of end-users or customer representatives with the software to verify its usability, functionality, and overall satisfaction. This allows you to make sure that the software meets the requirements and expectations of users. Acceptance testing also helps to identify potential risks, including legal ones.

During testing, additional defects and problems that were not noticed at previous testing stages may be identified and resolved. Thus, the acceptance testing process contributes to improving the quality of the final product.

Acceptance testing is a form of initial quality control that helps identify problems and defects while they can still be corrected relatively painlessly and inexpensively.

Functional acceptance testing vs non functional acceptance testing

Acceptance testing encompasses two primary categories: functional acceptance testing and non-functional acceptance testing.

Functional acceptance testing concentrates on verifying that the software system satisfies the prescribed functional requirements. It assesses whether the system executes the tasks and behaviors it was designed for, as outlined in the functional requirements. Functional acceptance tests ascertain whether the system handles user inputs accurately and generates the expected outputs, ensuring compliance with documented business rules and user stories. Examples of functional acceptance tests include validating login functionality, order placement, search capabilities, and other feature-specific functionalities.

In contrast, non-functional acceptance testing focuses on validating the non-functional aspects related to the quality of the software system. This type of testing ensures adherence to specified non-functional requirements such as performance, reliability, usability, security, scalability, and other quality attributes. Non-functional acceptance testing evaluates the user experience, ease of use, and adherence to industry standards and regulations.

Types of acceptance testing

User acceptance testing (UAT)

UAT is employed to ascertain the product's suitability for end-users. Its primary objective is to verify the software against business requirements. UAT test scenarios typically differ from system or functional test cases as they mirror the user's journey. For instance, when testing a website, it involves more than just step-by-step examination of all site functions; rather, it entails the user's free navigation through the site. This approach adds variability to the testing process, enabling the exploration of different behavioral models and evaluating how well the product aligns with them.

Business acceptance testing (BAT)

BAT is utilized to determine whether the product aligns with the business's goals and objectives. It primarily focuses on assessing whether the tested product can yield financial benefits for the company. Even if the software satisfies all technical requirements, it may still fail to pass BAT.

Contract acceptance testing (CAT)

CAT involves a contractual agreement that mandates conducting acceptance testing within a pre-agreed period after the product is put into production, and it must pass all acceptance tests outlined in the contract. The signed contract is referred to as a Service Level Agreement (SLA), encompassing conditions under which payment will only be made if the product meets all requirements as outlined in the contract. The contract must explicitly outline the testing timeline, testing areas, payments, and other relevant details. CAT ensures that the development of the software adheres to the contractual requirements and specifications specified in the project contract.

Regulation acceptance testing (RAT)

RAT evaluates the software's compliance with relevant industry norms, standards, or legal requirements. Typically, products or applications intended for release on the market must undergo the RAT procedure, as different countries or regions have distinct rules and regulations set by government authorities. This is particularly critical for products in sectors such as healthcare, finance, or government, where strict adherence to regulatory requirements is essential.

Operational acceptance testing (OAT)

Operational acceptance testing assesses the operational readiness of the product and falls under non-functional testing. It primarily involves testing recovery, compatibility, maintainability, reliability, and other aspects. OAT ensures the stability of the product before its release into production.

Compliance acceptance testing

Compliance acceptance testing verifies the software's compliance with the organization's internal policies, guidelines, and standards. It ensures that the software aligns with the organization's rules and regulations.

Performance acceptance testing

Performance acceptance testing evaluates the software's performance against specified criteria, including response time, scalability, and stability under various load conditions.

Security acceptance testing

Security acceptance testing examines the security features of the software to ensure protection against potential security threats and vulnerabilities.

Alpha testing

Alpha testing is an evaluation of the product in a dedicated test environment by a specialized team of testers, typically known as alpha testers. This testing phase replicates real-world interaction with the product from an end-user perspective. The primary objective of alpha testing is to determine whether the product functions as intended. It can uncover issues related to usability, functional deficiencies, compatibility, and more. Alpha testing is typically conducted when the product is 70-90% complete, just before beta testing.

Beta testing

Beta testing entails the assessment of the product by real end-users, who provide feedback aimed at enhancing the product. Typically, these users, known as beta testers, have unrestricted access to the product and are encouraged to offer their opinions on its design, functionality, and user experience, thereby aiding in the evaluation of its quality.

The primary question addressed by beta testing is: “Do customers find the product satisfactory?” This testing phase explains the product's appeal to customers and clarifies their anticipated usage patterns.

In contrast to preceding testing stages, beta testing involves a diverse array of devices, operating systems, browsers, and other variables. This facilitates the identification of errors and defects that may have eluded detection during internal testing.

Beta testing invariably follows alpha testing but precedes the product's market release. It is anticipated that the product will be at least 90-95% complete during this phase.

When to perform acceptance testing

Acceptance testing, the ultimate phase of product testing, typically occurs after system testing, thereby unfolding in the latter stages of the software development lifecycle.

Usually, acceptance testing is conducted by end-users or customer representatives, who serve as the intended users of the software. As they possess a deeper understanding of the business needs, expectations, and software requirements, they are well-equipped to execute effective testing. By simulating real-use scenarios, they ascertain whether the software aligns with their needs and preferences.

The sole exception to this rule is alpha testing teams, which predominantly involves company employees not directly involved in the product's development team.

How to write acceptance tests

Before conducting acceptance testing, it is essential to follow these preparatory steps:

Clarify and analyze project requirements. This involves understanding the business goals and user expectations. By doing so, you can determine the scope of acceptance testing and identify critical functional capabilities to be tested.
Develop a comprehensive test plan. A well-defined test plan outlines the acceptance testing strategy, scope, goals, available resources, and acceptance criteria. This plan serves as a roadmap for the testing process, ensuring its structure and organization.
Formulate test cases. Create detailed test cases that outline specific steps, inputs, and expected outcomes for verifying the software's behavior and functionality against established criteria. These test cases guide the test execution process and ensure thorough coverage.
Execute test cases in the test environment. Conduct the identified test cases in the designated test environment. Record the results and identify any discrepancies between expected and actual outcomes.
Analyze test results and prepare a detailed report. Evaluate the test results to assess the software's performance. Document any issues or deviations encountered during testing and provide a detailed report summarizing testing activities, results, and conclusions. This report serves as a valuable resource for stakeholders, aiding informed decisions regarding software deployment.

Let’s say your product is an online clothing store. An example of an acceptance test for this product could be:

Feature: purchasing a product in an online store

Scenario: the user can add a product to the cart and place an order

Given the user has opened the main page of the online store

When the user selects the product “T-shirt with print” on the catalog page

And the user adds the selected product to the cart

Then the user sees a notification about successfully adding the product to the cart

And the user goes to the cart

And the user sees the selected product in the list of cart items

And the user clicks the “Place order” button

Then the user navigates to the order placement page

And the user sees a form for filling in personal data and delivery

And the user fills out the form with correct data

And the user clicks the “Submit order” button

Then the user sees confirmation of successful order placement

This acceptance test checks the basic functions of the online store, such as adding a product to the cart, going to the cart, placing an order, and successful payment.

Advantages and disadvantages of acceptance testing

Like any type of testing, acceptance testing has its own advantages and limitations.

Advantages of acceptance testing

Involves users in the testing process, facilitating the identification of defects missed at previous testing stages
Allows for automated execution of tests, streamlining the testing process and enhancing efficiency
Increases confidence and satisfaction among customers, as they directly participate in the testing process

For example, in a software project for a social media platform, let’s say the testing team tests a new feature that allows users to schedule posts. During acceptance testing, a user encounters difficulty while trying to navigate the calendar view to select post dates. The user provides feedback on the usability issue, prompting the development team to improve the calendar interface before the feature's official release. This demonstrates how user involvement in acceptance testing can lead to valuable insights and improvements in the software's functionality and user experience.

Disadvantages of acceptance testing

Users must possess basic knowledge of the product, which may limit the pool of eligible participants for testing
Not all users may be willing to participate in the testing process, which can affect the diversity and representativeness of feedback
Obtaining and structuring feedback can be challenging, as multiple users may offer differing opinions and express them differently, achieving full test coverage for all possible scenarios and user interactions may also be difficult
Coordinating and planning the participation of real end-users in testing poses logistical challenges, such as scheduling conflicts and availability
End-user assessments are often subjective and may vary, making interpretation and decision-making challenging for the development team

For example, in an ecommerce platform, during acceptance testing of a new checkout process, several end-users provide feedback on the placement of the “Place Order” button. While some users find it intuitive, others suggest moving it for better visibility. This variability in user opinions complicates decision-making during the development process for the team, as they strive to optimize the user experience.

Bridging the gap between software and user needs

Acceptance testing serves as the pivotal link between software development and user satisfaction. It acts as the final quality assurance checkpoint, ensuring that the delivered product not only meets technical specifications but also aligns with the practical needs and expectations of end-users. By involving real-world users in the testing process, acceptance testing uncovers valuable insights and usability issues that may have been overlooked during earlier testing stages. This user-centric approach empowers development teams to refine the software based on actionable feedback, ultimately enhancing the overall user experience.

In today's dynamic landscape of evolving user expectations and increasing software complexity, the importance of acceptance testing cannot be overstated. It serves as a strategic asset for organizations striving to create software solutions that resonate with their customers. By bridging the gap between development and real-world usage, acceptance testing ensures that the delivered software not only meets business objectives but also delights users with its functionality and usability. As organizations continue to prioritize customer satisfaction and business success, acceptance testing remains an indispensable tool for delivering high-quality, user-centric software solutions.