How to Create Functional Tests with Extensive Coverage

Everyone can write decent functional test cases. Writing documentation for functional testing services that have thorough coverage is a different skill. It mainly depends on your expertise and a little bit on professional obsession. Changing your state of mind is much harder than enriching own knowledge. But as for the latter – we’re here to help you with that.

What Are Functional Tests?

If you’re looking for best practices to extend the test coverage in manual software testing, you must be familiar with the basics. Nevertheless, we’ll add a piece for beginners who are trying to dig deeper from the start.

In software QA, a functional test focuses on verifying whether the software functions correctly and meets its intended functionality. The primary goal of is to ensure that the product behaves as expected based on the business requirements and functional specifications.

Functional Test Case Examples

Below are a few examples of functional test cases for an e-commerce platform (can be a mobile or web application).

Test Case #1: User Registration

ID: TC-1.1

Pre-conditions: The user has not registered on the website.

Summary: Verify user registration.

Steps to reproduce:

1. Open the registration page: link to the website’s registration page.
2. Enter preferred email and password.
3. Click “Register.”

Expected result: The user is successfully registered and redirected to the homepage.

Test Case #2: Search Functionality

ID: TC-1.2

Summary: Verify the search functionality.

Steps to reproduce:

1. Enter a search query in a search bar.
2. Click on the search icon.

Expected result: The search results page displays relevant products matching the search query.

Test Case #3: Adding Products to Cart

ID: TC-1.3

Summary: Verify adding products to the cart.

Steps to reproduce:

1. Open a product page.
2. Click on the “Add to Cart” button.

Expected result: The product appears in the shopping cart. The cart icon is updated to display the addition.

Other Functional Test Cases

You can find more test templates in in one of our earlier articles: How to Write Test Cases: a Comprehensive Guideline.

Other functional test examples will include profile update, password reset, adding reviews, chat with the support, sorting and filtering, etc. As mentioned above, everything that refers to the “features” part will fall under this category.

Keep in mind that one feature can be checked within both functional and other test suites. The difference between these cases is that in functional testing we verify the behavior against documentation (and, thus, expectations): if a user clicks this, what happens next?

During non-functional testing, there are other questions to answer. If a user clicks this, how much time does it take for a page to open? Will the result meet the W3C standards? And so on.

The Bond Between SRS & Functional Tests

Before testing, you always dive into software requirements specifications. We do this not only to learn about the product, but also to find out what tests would entail for a specific system. For functional testing, SRS guides your approach to it by outlining what is a functional test in a particular project.

1. Functional requirements – what actions a system should perform. Here, you check that software does what it should.
2. Use cases and user stories – the sequence of steps users perform to achieve exact objectives. Here, you investigate user-software interactions.
3. Business rules – operational or decision-making guidelines that a system should follow. Here, you verify the correct execution of business logic.
4. Data processing and manipulation – terms of data processing and manipulation. Here, you validate the accuracy of data input, transformations or calculations, and outputs.
5. User interfaces – behavior and functionality of user interfaces. Here, you assess user actions, input validation, button functionality, form submissions, screen navigation, etc.

Studying the SRS is the first variable that impacts the completeness of test coverage. You grasp what, how much, and how to test. After that, you can begin tailoring a functional testing plan to secure vital software areas.

The Definition of Test Coverage

Now, we need to understand the concept of test coverage. Fundamentally, it measures how much of a system’s code, functionality, or requirements were tested.

Imagine you have this bit of information for a functional requirement within an SRS document:

• Functional Requirement: User Authentication.
• Description: The system shall provide user authentication functionality to ensure secure access to the application.
• Details: The system shall allow users to create new accounts when provided with a unique username, email address, and password.

To fully cover this requirement, you wouldn’t necessarily execute one test (creating an account with valid inputs). Because inside this feature, there are sub-functions that specify what the system does if:

• The user name is invalid.
• The email address is incorrect.
• The password is weak.

Thus, to cover this particular functional requirement, you must run a few tests corresponding to various scenarios. And if you were to tackle only the successful outcome of user registration, your test coverage would be 25%.

Test Coverage & Code Coverage

To better understand the concept of test coverage, you should also get to know what code coverage is.

Without overcomplicating things:

• Test coverage is about working with the areas critical for users and stakeholders (e.g., functional requirements and business logic).
• Code coverage analyzes which parts of the code (statements, branches, functions, or lines) are exercised during testing.

Commonly, code coverage review is the development team’s task. They use specialized tools or frameworks to evaluate the coverage of the code during development and unit testing. There are various code coverage types that help secure thorough testing and handle multiple elements.

• Statement coverage – how many lines (statements) of the code were executed during testing.
• Branch coverage – what possible outcomes of conditional (if-else) statements were tested.
• Condition coverage – which combinations of conditions within a program were tested.
• Function coverage – how many functions in the code were activated during testing.

As we’re centering on QA resources, we won’t dive into the fancy chaos of code. Instead, let’s move on to the types of test coverage.

Types of Test Coverage

For software testing services, types of test coverage determine what aspects of the system you would cover. We’ll discuss the top three you could benefit from.

Risk Coverage

Risk coverage is assessing and mitigating risks associated with software development and its potential impact on the product. It involves identifying and prioritizing risks and designing tests specifically targeting those risks.

Consider a risk associated with an e-commerce website’s payment processing with a potential for transaction errors. In this example, your functional tests should address areas or events that could compromise financial operations. Say there was an interrupted API request or a user typed incorrect credit card info. Hence, you would need to investigate system behavior in these instances.

Requirement Coverage

Requirement coverage is about testing software requirements. Here, you validate that the product meets the intended functionality, business objectives, and user expectations defined in SRS.

Suppose you see this requirement in the document: “The marketing software should provide email campaign analytics, including open rates, click-through rates, and conversion rates.” Examples of functional test cases that would cover this could include:

Test Case #1: Open Rate Calculation

Test Objective: To verify that the marketing software accurately calculates the open rates for email campaigns.

Test Steps:

• Create a test email campaign.
• Select users 1-5 as recipients.
• Press the “Send” button.
• View the open rates.

Expected Result: The displayed percentage of recipients who opened the email equals the actual percentage of opened emails.

Test Case 2: Click-Through Rate Calculation

Test Objective: To verify that the marketing software accurately calculates the click-through rates for email campaigns.

Test Steps:

Create a test email campaign with clickable links.
Select users 1-5 as recipients.
Press the “Send” button.
View the click-through rates.

Expected Result: The displayed percentage of recipients who clicked on the links in the email equeals the actual percentage of click-throughs.

Test Case 3: Conversion Rate Calculation

Test Objective: To verify that the marketing software accurately calculates the conversion rates for email campaigns.

Test Steps:

Create a test email campaign with specific conversion actions, such as form submissions or purchases.
Select users 1-5 as recipients.
Press the “Send” button.
View the conversion rates.

Expected Result: The displyed percentage of recipients who completed the conversion equals the actual percentage of conversions.

And, yes, you could include clickable links and specific conversion actions to kill three birds with one stone. But this is more about how efficiently you plan functional testing. For this section, the cases above demonstrate what it would mean to cover the proposed requirement.

Product Coverage

Product coverage establishes which product features, functionalities, and user scenarios are tested. It aims to ensure that all aspects of the project are thoroughly examined to uncover defects, validate functionality, and meet the specified requirements.

For illustrative purposes, say you need to test a taxi booking app. You wouldn’t simply check whether you can order a ride. For users, there are other points of importance:

• Can they change locations after the vehicle departs?
• Can they cancel the ride?
• Can they see drivers’ current routes?
• Can drivers refuse pickups?
• Can drivers exit the app without interrupting the session?

So, to achieve optimal product coverage, you need to test every feature that affects the software’s value for users and stakeholders.

Now, let’s recap what each type of test coverage means for your test cases:

• Risk coverage – writing tests that target error-prone areas.
• Requirements coverage – writing tests that target requirements stated in SRS.
• Product coverage – writing tests that target value-delivering features to users/stakeholders.

Achieving Thorough Coverage

You certainly know how to write good test cases. Attaining comprehensive coverage is more about what you do before creating them.

Familiarize Yourself with the Industry

Being informed is being prepared. Often, learning about industry specifics gives you an edge when writing functional test cases. For example, particular niches commonly have “typical” high-risk areas, e.g., data interpretation and payment processing for medical and B2B e-commerce software. So knowing your sector means your testing efforts will be more precise industry-wise.

Study Your SRS

SRS knowledge helps you create test cases that cover all specified requirements, ensuring thorough testing. Similarly, you should pay great attention to use cases and acceptance criteria. These let you understand each requirement on a deeper level and make positive test cases that exhaustively tackle every function.

Keep Your Work Scope Organized

Well-structured test cases can become your testing plan and a tracking tool. You can also transform them into a roadmap that motivates you to take a step back and analyze the whole picture. And by prioritizing areas for testing, you can effectively “branch out” into other aspects.

Take Advantage of Test Design Techniques

As noted in one of our articles, good knowledge of five test design techniques help you write better test cases. When you systematically design tests based on suitable techniques, you achieve higher coverage of different system states, inputs, and conditions. You can also always use negative testing and edge cases to maximize your testing outreach.

Optimize Your Functional Test Cases

Remember the example with functional test cases for marketing software? The efficiency of your tests also substantially affects the test coverage. Depending on the project, you can combine some cases or write individual tests to explore a feature fully. Productively arranging the test cases will also give you more time for other tasks.

Maintain Your Test Cases

Regularly update your test cases to guarantee accurate and up-to-date testing. Test cases can become obsolete when there are software alterations, such as new features, bug fixes, or requirement changes. And for projects that undergo frequent amendments or have a dynamic environment, maintaining manual tests becomes crucial.

To Sum Up

Mastering something is a long journey. And you can’t achieve complete proficiency without determination. So, if you’re reading this – you’re well on your way to becoming a true QA talent. When you realize your potential, you may find that professional obsession that breaks the mold of quality testing.

Good luck, and keep learning.