What is Integration Testing? Its Importance, Implementation, Advantages and Approaches

Quick Summary: Bug-infected software can affect the overall functionality of businesses. As an outcome, testing the software at every development phase is imperative. Integration testing is the second level of the software testing process, helping fill the gap between unit testing and system testing. In this blog, you will explore integration testing, its advantages, tools, how to perform it, and more.

People in this technologically advanced era need cutting-edge software solutions with better functionalities and a faster delivery time. As a result, developers are compelled to rush testing, reasoning that it’s preferable to deploy software solutions on (or very near to) the release date than to undergo a long delay.

On the other hand, software solutions with bugs can result in terrible public relation disaster and backlash. This is why developers must publish software solutions and applications that have passed rigorous testing.

As mentioned by Forbes, poor testing quality reportedly costs software organizations a staggering $2.8 trillion US dollars.

Unfortunately, the real cost is much more than a monetary loss. Wondering what? When a smartphone user encounters a software glitch, they uninstall the application right away. Therefore, in order to prevent such financial loss, organizations need to understand the importance of software testing.

For that purpose, today’s discussion will concentrate on a particular testing subject: Integration testing.

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Integration testing is one of the significant automation testing types. Hence, integration testing takes up an unavoidable place in the testing lifecycle. This is because it verifies the integrity of the entire application before thorough system testing.

Therefore, in this article, we’ll discuss integration testing, why it’s required, its advantages, approaches, objectives, best practices, integration testing tools, and even an example of integration testing.

Without any fuss, let’s begin by defining the term.

What is Integration Testing?

After unit testing, integration testing is considered the second phase of the software testing process. Integration testing involves examining individual elements or units of a software project to uncover vulnerabilities and faults to ensure expected functioning.

The typical software project often comprises multiple modules, many of which are created by separate developers. Integration testing illustrates to the team how well these various components interact. After all, each component may perform flawlessly, but the crucial issue is whether they can continue to function well when combined.

Therefore, integration testing determines whether different components of software applications can work hand in hand.

Why is Integration Testing Necessary?

Integration testing is essential in today’s IT and software development environments, especially when you have a project with tight deadlines and dynamic objectives. The application may still have bugs even after running unit tests on each module.

Hence, integration testing is essential to find these loopholes and ensure that the integrated components function properly.

So, integration testing is important for the following reasons:

Combining Separate Modules into a Viable Application

When multiple developers work on different modules, each of them contributes logic and ideas to the development process. This might lead to usability and functional issues. Integration testing can ensure the combined components work as intended as a whole and adhere to the given requirements.

Addressing Common Challenges Missed by Unit Testing

Some modules that communicate with external application program interfaces (APIs) must be tested to ensure they work as intended. Integration testing is, therefore, necessary because this might not be accomplished during unit testing.

Ensure That the Application Incorporates Changing Demands

Requirements can frequently change in many real-time application environments. The additional parameters might not always be unit tested, which could result in overlooked flaws or missing product features. These loopholes can be addressed via integration testing, guaranteeing software maintenance, and ensuring new standards are incorporated into the final product.

Eliminating Other Basic Problems

Different types of integration testing help eliminate issues, including inadequate exception handling, wrong API response generation, incorrect data formatting, inaccurate external hardware interfaces, inappropriate third-party service interfaces, and error traps.

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Objectives of Integration Testing

We know you’re wondering - what is the key objective of integration testing? Or what is even its purpose?

So, let’s have a look at them.

• To Examine the Functionality of Integrated Software Modules

One of the main objectives of integration testing is to verify the connectivity between different modules by looking at the logic. The executed logic and its rendering values must be in accordance with the test plan’s specifications.

• To Ensure That Modules and Third-party Tools Integrate Seamlessly

To ensure that the data retrieved by API is accurate and that the intended output is being generated, it’s necessary to examine the interactions between modules and third-party tools.

• To Address Exception Handling Issues

Before releasing the final version, integration testing identifies problematic zones and gives warning signs to reduce exception handling issues. After the solution is released, fixing undetected integration issues is expensive. Therefore, in order to eliminate the flaws in advance, the developers and testers must perform an in-depth system-level study.

Different Approaches of Integration Testing

Now let’s move ahead and seek an answer to another crucial question- what are the types of integration testing?

In essence, there are four types of integration testing available, as mentioned below:

1. Bottom-Up Integration Testing – Bottom-up testing involves testing each module with higher-level modules until all software modules are tested. Each subsystem’s integration with other subsystem modules is tested as a part of the integration testing process.

Test drivers are used in this integration test to drive and transmit the real data to the lower-level modules.

2. Big-Bang Integration Testing – Among all other types of integration testing, the Big-bang approach is the simplest one. In this methodology, all the modules are integrated, and the functionality is verified after completing separate module testing.

In simple words, the system’s modules are just integrated and tested. However, debugging issues discovered during this type of integration testing are very expensive to resolve.

3. Top-Down Integration Testing – Top-down approach is utilized to replicate the functionality of lower-level modules. This integration testing involves a top-to-bottom testing approach.

High-level modules are tested foremost, followed by low-level modules, to ensure the system operates as intended. Lastly, low-level modules are integrated into high-level modules.

4. Mixed Integration Testing – It is also known as sandwiched integration testing. Mixed integration testing employs both bottom-up and top-down testing approaches. The top-level module must first be coded and unit-tested before testing can begin in a top-down method. In the bottom-up approach, testing can only begin once the lower-level modules are complete.

Therefore, the flaws in top-down and bottom-up approaches are fixed by sandwiched or mixed integration testing.

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Integration Testing Example

Let’s now consider a mobile application with a video streaming feature as an example of integration testing. Going through the example will make the learning part easier and more informative.

Mentioned below are some of the essential features of video-streaming mobile applications:

• Log in or sign up.
• View different yearly/monthly subscription packages.
• Pick personalized or customized plans.
• Watch any video feed.

After downloading the applications, users are presented with a sign-up form where they can provide their account details. After proper authorization, they are routed to a page that lists different subscription plans. After the user chooses their subscription plan, they can finalize the payment.

Any mistakes in this logical progression are problematic for the user and can result in financial losses for the app developer. This is why developers should be familiar with emerging software testing and quality assurance trends, also helping them perform testing in efficient ways. Moreover, these issues are recognized and rectified with the help of integration testing.

Thus, testers perform unit testing after the preparation of each module. When all modules are accessible, testers test them all at once to examine their data flows and interfaces. The end user should be able to finish their payment if no errors are found successfully.

Advantages of Integration Testing

We’ll now go through some of the significant advantages of integration testing:

• Every integrated module is tested to ensure proper operation.
• Integration testing also reveals interface flaws.
• Once a module is finished and prepared for testing, testers can start integration testing. They do not need to wait for other modules to finish and can get prepared for testing.
• With the help of integration testing, testers can find all kinds of bugs, flaws, and security breaches.
• Integration testing gives testers a thorough review of the entire system. This significantly lowers the probability of serious connectivity failures.

In the next section, we’ll get a quick overview of the significant steps to perform integration testing, the difference between unit testing and integration testing, integration testing tools, and the best practices.

How to Perform Integration Testing?

Regardless of the types of integration testing approaches, we discussed above, let’s get a brief overview of the fundamental steps:

1. Plan and design the integration test schedules.
2. Create the test scripts, scenarios, and different cases.
3. Implement the test cases succeeded by reporting the flaws and loopholes.
4. Track the vulnerabilities and re-test them.
5. Until integration is completed successfully, steps 3 and 4 are reported.

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Difference between Unit Testing and Integration Testing

Let’s go through the difference between unit and integration testing with the help of this short and sweet table:

Now you know about the major difference between unit and integration testing.

However, if you want to know more about unit testing and its comparison with other types of tests, you can also go through our article on unit testing vs functional testing.

What are the Popular Integration Testing Tools?

Software testers now have access to a wide range of integration testing tools. Here are some examples:

1. LDRA

It offers a variety of integration testing tool sets that comply with various organizations’ regulatory guidelines. Furthermore, LDRA is an open-source tool that offers a wide range of services, including design reviews, static analysis, dynamic analysis, code coverage, and more.

Special features:

• Enables efficient execution of unit and integration testing
• Supports a common environment ideal for integration testing
• Automates software certification and approval evidence

2. Citrus

The open-source testing framework, Citrus, is ideal for doing complicated integration tests. It supports various protocols, including SOAP, JMS, and HTTP.

Special features:

• Sustains error recreation
• Allows tester to verify the database
• Provides test coverage and test plans

3. VectorCast/ Ada

By automating much of the testing process, this tool greatly reduces the time and cost for unit and integration testing projects. Additionally, it creates missing modules using stubs and drivers to replicate code functionality.

Special features:

• Offers generic test cases appropriate for regression testing
• Automatically generates code for stubs and drivers
• Integrate with a variety of other tools, like IBM Rational and Green Hills

4. Tessy

Tessy, a tool specifically created for embedded software, manages all facets of test organization, including requirements, traceability, and management.

Special features:

• Provide a comprehensive test report
• Includes software maintenance and support for various programming languages
• Using a single license, several users can access the tool

Tips and Tricks for Integration Testing

Because of our diversified expertise in developing software applications, we’ve learned and are well acquainted with integration testing best practices. Here they are:

• Firstly, establish an integration testing strategy, then create the test cases and test data following it.
• Learn about the application’s architecture design and determine the essential modules. Testing on them must be done on a priority basis.
• Get the interface designs from the architectural team, then develop test cases to thoroughly check each interface. It is essential to carefully test the interface to the database, external hardware, and software application.
• It would be best if you understood that test data is the next most important component after the test cases.
• Before execution, always have the mock data ready. When running the test cases, avoid choosing test data.

ConclusionIntegration testing is an important part of your Software Testing Life Cycle (STLC). You can seamlessly eliminate the post-release upgrades and bug fixes if you implement them properly.At Radixweb, a trusted software development company, we’ve worked on projects where integration testing appeared to be the quickest approach to uncovering flaws in how modules interact.Experts at Radixweb are well-acquainted with intelligent automation testing techniques. They implement it and transform your software applications into next-gen solutions, helping your business to succeed with flying colors.Therefore, we are your one-stop offshore partner for out-of-the-box performance and growth.Please contact us as we’ll love to discuss your requirements and preferred timeframe for software testing environments.