What Is Functional Testing And Why Is It Important?

What Is Functional Testing?

Functional testing helps to make sure that developers create an application according to outlined requirements. While testing, the testers will check each function of the software program. They will compare the test result with the expected result.

It helps developers know if an application works according to specified expectations or not. The test is usually performed by the Quality Assurance team.

While testing, each function will receive a specific value to determine its output. The testers will compare the result with the specified requirements. This gives them an insight into how accurate and efficient the application is. If the output is the same as the specified result, the software passes the test. Otherwise, they have to make some changes to it.

Functional testing is otherwise known as black box testing. This is because the testing covers only the specifications, not the code itself.

While the code may seem to work well, it is important to test the different sections of the application. That is how to find out if the application will still work after combining the components.

For instance, when testing a payment software application, the team will check the software for accuracy. The team will test whether it is accurate after performing an operation on a user’s account.

It may check if the software balances a user’s account accurately after each transaction. It will fail the test if it gives a balance of $5,000 after withdrawing $2,000 from $10,000 in a user’s account instead of $8,000.

The testers may also receive an error message while testing the software. That indicates that the software has some bugs. The developers must fix the problems before the software functions optimally.

Types Of Functional Testing

Types Of Functional Testing

The Quality Assurance team performs a series of functional tests. Some of such tests are:

1.  Smoke Testing

Smoke testing takes place after developers have built the software. The developers aim to know if all the software’s functions are working properly. This test comes before they perform regression or functional tests on the software.

Smoke Testing has a specific goal: to reject a broken application. This is so the QA team doesn’t waste time installing and testing a software application that doesn’t pass the test. This saves them a lot of time they would have otherwise spent on handling issues that may arise.

2.  Sanity Testing

Sanity Testing is done when the testers don’t have the luxury of time for testing. The Quality Assurance team will check some elements of the software. This includes the functions, menus, and commands. They want to ensure that these parts of the software are working as expected.

3.  Integration Testing

Integration testing is commonly used to test each unit of a software application. To use this testing method, the developers will develop a unit. They will test it as a standalone. After the testing, they will integrate it with other units.

4.  Regression Testing

This testing method involves executing test cases repeatedly. The testing checks whether the previous functionality is working fine and the new changes have not introduced any new bugs.

The team can test a program or code snippet with this method. The QA team performs this test when the developers have changed the original functionality of a software application. This enables the team to be sure of the program’s accuracy regardless of the changes made to it.

5.  Beta/Usability Testing

Usability testing is an advanced form of testing. Testers check whether a function works with functional testing. Usability checks if it works well enough for users. Customer satisfaction is the motive behind the Beta/Usability test.

Functionality testing precedes usability testing in order to have valid and quantifiable feedback from the testers who are using the application. Beta/Usability testing is the last testing done on a software application. This happens before it is released to the public.

6.  Database Testing

The testers conduct database testing too. They wish to know if the database will work according to specified requirements. The tested items are the database tables, schema, and triggers. The test may also cover the database’s responsiveness. This is alongside data consistency and integrity.

The QA team may also go through the information in the database to see if they are properly stored or not. It must also check if pieces of information sent to the database is lost in transit or during storage.

7.  Ad-Hoc Testing

This is an informal testing type. It doesn’t follow a specific procedure or activity. Any part of the application can be tested randomly. This can be done to find out if any part of the software program needs fixing.

What is Functional Testing?

Functional Testing Best Practices

Getting the best out of functional testing requires the tester to follow the right procedure. Here are some best practices or procedures that may assist the QA team to perform a thorough functional test:

1.  Gather Necessary Information

The tester must be familiar with what they want to test. They must also understand what the testing procedure or plan is. They can get relevant information from the development team about processes and user commands. These pieces of information will provide insights for the QA team.

What the market needs for product demand is another important factor. The testing team should be aware of this. They must also prepare a matrix or document that will serve as a link between the product and the test cases and requirements. If there are changes in requirements, they should change the matrices to reflect the changes.

2.  Make Test Cases and Test Plan

The team should have a detailed plan of what they need for the testing. This should include the scope and goals of the testing. They should also consider the hardware, number of personnel, and necessary software tools for testing. They shouldn’t overlook the number of test cases needed to carry out the testing.

The test cases should be arranged in order of priority. This is time-saving and reduces risks and unnecessary delay. The team should review these plans in detail.

3.  Execute the Test

Before executing the test, the team should ensure that the functionality matches the test plans. This is needed for correct execution of the test.

While writing the test cases, they should make room for modification when necessary. The needs for the product may change, making modification inevitable.

To make a detailed analysis, it is important to document the problems they face during the testing. The solutions to such problems should also be documented.

4.  Give Automated Testing a Shot

They may consider automated testing. This testing method has some benefits: it saves time and improves the product’s quality. It is a bit more expensive in the short-term, but, it offers long-term benefits. It is left to the tester to choose the part of the software they intend to adopt this testing method for.

Testers shouldn’t opt for automated testing where manual testing is more ideal.

5.  Manage Data Storage System Defects

If several people are testing the same functionality, it may trigger some problems. This may result in getting wrong defects or repeating defect reports. Such errors may affect the test results.

A practical solution is using a centralized data storage system. The system should be accessible to any member of the team. It should also have some important features that will make the process seamless. This includes standard templates for defect verification and reporting. It should give insight on how to rank defects according to tasks assignment and priority.

6.  Reporting Test Results

The team should report the test results in a format that is easy to read and understand. They need to include a summary of all the test cases they executed. The report should include the time taken to test each stage of the tested features. Progress and status should also be included in the report. If they find new errors during the testing, the report should mention that as well.

The QA team should present the report in a simple and clear format for the developer for necessary actions.

7.  Analysis

The analysis stage allows the team to detect problems in both development and testing. It also offers them options to choose from. If there is any room for improvement in product development, the analysis helps them to understand what they need to do to improve the procedure. Analysis is crucial to product success.

What Do You Test?

Functional testing focuses on reviewing the functionality of a software application. It covers the following areas:

  • Accessibility: The testing will check a function’s accessibility.
  • Basic Usability: What is the UX? How usable is the system? Can users find their way around the system without difficulty? The testing will provide answers to these questions.
  • Error Condition: They will test the condition of errors in the software too. The test enables testers to see if the software will display appropriate error messages.
  • Mainline Functions: The focus is on the main features of the software. Every aspect of the application is tested to double check everything is working as it should.

General testing is the QA’s way of ensuring that only a fully functional software application is released for public use. This is to give users the best experience using the application.

Functional Testing Process

Functional testing, except the ad-hoc type, is not done randomly. The QA team must follow a step-by-step process. This is how they are able to arrive at accurate results from the tests.

Here are the steps:

  1. Understand the software requirement

They must first understand the specified requirements. This involves knowing the functions the software must perform.

  1. Identify the test input data

The team will use test data to identify the inputs.

  1.     Compute the expected outcome with the selected input values
  2.     Execute the test cases
  3.     Compare the actual and computed result

The success of functional testing depends on the test conditions used. Note that the best test conditions are those created from business or user requirements.

If the team develops the test cases from design documents or system requirements, testing may not be enough to detect errors in the documentation. If these errors affect the users’ experience, they may dump the application for a competitor’s.

Functional Testing Checklists

Before proper testing, a comprehensive checklist is prepared. The checklist includes the following:

  • Identify the aim of the testing.
  • Define the objectives, scope, and goals of the test.
  • Understand the business specifications and requirements. Study and analyze them based on the test plans, strategy, and test cases you want to sort out.
  • Create a list of dedicated people for the test.
  • Create a detailed test strategy or plan before starting the process. Select the best methods, approaches, and practices that will give you the best result. Some of the best testing techniques are already discussed in the article.
  • Design test cases to boost the flow of activities. In functional testing, the team use test cases to test the application’s interface. They also test how the user interacts with the application.
  • Prioritize the critical aspects of features of the product. Test these first.
  • Find the right tool for testing.

Functional Testing Tools

Testers have several testing tools at their disposal for functional testing. This is a list of the most used tools:

Tools Features
Sahi This is an open-source automation testing tool. It is an Apache product. It is also licensed for testing web applications.

It is written in JavaScript and Java, making it an effective testing tool. You can run it on proxy serve because it’s browser-independent.

It is lightweight, robust, and scalable. It provides in-built reports as well.

Watir This open-source tool stands for Web Application Testing in Ruby. It is a great tool for web browser automation.

It uses the easy to read and concise Ruby scripting language.

The tool is very flexible and easy to use.

Maintaining test cases is easy with the tool too.

It supports an array of web applications regardless of their sources.

It makes database connectivity possible. So, testers can use it to read spreadsheets and data files.

Selenium Selenium is another open-source tool for functional testing. It works on both desktop and web applications.

It offers testers the freedom to customize automated test cases.

It supports the testing of a text case over many browsers.

Cucumber Developers used Ruby language to write this testing tool. They can use it to test a wide range of languages such as C#, Java, and Python.
SilkTest SilkTest is a product of MicroFocus International. This testing tool can test web, enterprise, and native applications.

It is quite portable and robust, making it a reliable testing tool.

In addition to supporting mobile platform, SilkTest also enables testing across several browsers.

Testers can test a case with a specific keyword.

Canoo WebTest This platform-independent functional testing tool is also open-source. It is pretty fast and easy to use.

It is so flexible that they can extend it to meet growing requirements.

It has an excellent reporting system. It enables testers to understand whatever failure they experience during testing.

Rational Functional Tester IBM developed this testing tool through its Rational Software division.

It can perform both regression and functional testing for software application testing.

This testing tool supports an array of applications. Adobe Flex, .Net, SAP, web-based applications, AJAX, and Java are some of them.

The tester supports Windows and Linux only.

SoapUI SoapUI is another open-source functional tool. It supports a wide range of protocols such as SOAP, HTTP, and JDBC.

Functional Vs. Non-Functional Testing

How does functional testing compare with others? Here is a comparison of functional and non-functional testing:

Functional Testing Non-Functional Testing
Functional testing involves software testing. The testing will find out whether an application meets the specified requirements. This testing checks some aspects of a software system. It covers reliability, performance, and scalability tests.
Testers can do manual testing with ease. Manual testing is usually difficult to do.
This testing comes first. It comes after functional testing.
Functional testing works with business requirements. Scalability, speed, and other performance parameters are the inputs.
Automation tools or manual testing are the options. Tools are used.
It describes the functions of the product. It focuses on how efficient the product is.
Some typical examples are Regression Testing and Unit Testing. Others are Integration Testing and User Acceptance Testing. Stress Testing, Volume Testing, Installation Testing, and Compatibility Testing are common examples.

Advantages Of Functional Testing

Some of the advantages of functional testing include:

  • It ensures customer satisfaction.
  • The end product is usually defect-free.
  • Safety and security guaranteed.
  • Improved product quality.
  • It also ensures that all the functionalities work well.
  • There is an assurance that all specified requirements are met.

Disadvantages Of Functional Testing

Some notable cons include:

  • It can miss some logical or critical error in the application.
  • Redundant testing is possible.

The core of every application is the UX. If an app is not serving the users as it should, it will attract negative reviews. Then, users will start looking for better alternatives. So, functional testing should be a fundamental part of every app before releasing it to the general public. Test your app and fix the bugs before going live.

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