Integration Testing

Integration Testing in SDLC

In this article, I am going to discuss Integration Testing in SDLC. Please read our previous article where we discussed Unit Testing. At the end of this article, you will understand the following important pointers which are related to Integration Testing in SDLC.

  1. What is Integration Testing?
  2. Why Should Integration Testing Be Done?
  3. How are Integration Tests Conducted?
  4. Types of Integration Testing
  5. Big Bang Integration Testing
  6. Bottom-Up Integration Testing
  7. Top-Down Integration Testing
  8. Mixed or Sandwiched Integration Testing
  9. When Should Integration Testing be Automated?
  10. Criteria for Integration Testing’s Entry and Exit
  11. What are the Advantages of Integration Testing?
  12. What are the Disadvantages of Integration Testing?
  13. What is the Difference Between Integration Testing and System Testing?
What is Integration Testing?

After unit testing, the software testing process moves on to integration testing. During this testing, units or individual software components are tested jointly. Finding problems in the interactions of integrated components or units is the aim of the integration testing level. Integration testing is the process of analyzing the interface between two software modules or components. The correctness of the interface is the main concern.

Integrity testing is performed to find problems with the interactions between integrated units. After all the components have been unit tested, integration testing is conducted. The goal of the software testing technique known as “integration testing” is to confirm how various software application modules or components interact with one another and share data.

Integration testing aims to find any issues or bugs that develop when various components are joined and communicate with one another. Normally, system testing comes after unit testing and before integration testing. Early in the development cycle, integration difficulties can be found and fixed, lowering the likelihood of later, more serious, and expensive problems.

What is Integration Testing in SDLC?

Why Should Integration Testing Be Done?

In addition to the general requirement that they test all software before making it accessible to the public, developers should perform integration testing for a number of specific reasons:

  • Errors can be brought on by incompatibility between software modules.
  • The ability of each software module to communicate with the database must be verified by developers.
  • Client input causes requirements to change. Though perhaps they haven’t been extensively tested yet, those additional needs should be.
  • Every software developer has their own conceptual framework and coding rationale. Integrity testing guarantees that these diverse units work together seamlessly.
  • Compatibility issues with the hardware could arise.
  • Because modules typically connect with third-party APIs or tools, integration testing is essential to guarantee that the data these technologies receive is accurate.
How are Integration Tests Conducted?

Regardless of software testing methodologies, the integration test procedure is conducted:

  • Create a plan for the integration tests.
  • Create the test cases, scripts, and scenarios.
  • Carrying out the exam Cases was then followed by defect reporting.
  • Monitoring and re-testing the flaws.
  • Up until the successful completion of Integration, Steps 3 and 4 are repeated.

Types of Integration Testing

There are four different techniques for integration testing. The following are those methods:

Big Bang Testing:

Big Bang Testing is an approach to integration testing in which all the modules or components are integrated at once and tested as a whole. During testing, this assembled collection of components is regarded as a single entity. The integration process won’t run if all of the unit’s components aren’t finished.

Big Bang Testing

  1. It is practical for compact systems.
  2. Straightforward and uncomplicated approach.
  3. Can be finished promptly.
  4. Is not complicated to plan or coordinate.
  5. Possibly appropriate for small projects or systems with less interaction between components.
  1. Because you would need to wait for all the modules to be merged, there will be a significant delay.
  2. All modules are looked at once, therefore high-risk, crucial modules are not separated out and checked first.
  3. Unsuitable for lengthy projects.
  4. High likelihood of challenging to recognize and diagnose integration issues.
  5. Long and difficult debugging and troubleshooting processes may ensue from this.
Bottom-Up Integration Testing:

In bottom-up testing, all modules are tested in conjunction with higher-level modules. Each subsystem’s interfaces between the many modules that make up the subsystem are tested as part of the integration testing process. To drive and pass the necessary data to the lower-level modules during this integration testing, test drivers are used.

Bottom-Up Integration Testing

  1. Stubs are not necessary for testing from the bottom up.
  2. The ability to simultaneously test numerous disconnected subsystems is a key benefit of this integration testing.
  3. Setting up the test conditions is simple.
  4. Favorable for applications that employ a bottom-up design strategy.
  5. The test findings are simple to see.
  1. Producing driver modules is necessary.
  2. The complexity that develops when a system is composed of numerous small subsystems is tested in this study.
  3. There is no working model that can be depicted as far as the modules are concerned.
Top-Down Integration Testing:

Top-down integration testing simulates the behavior of lower-level modules that have not yet been integrated. This integration testing involves top-to-bottom testing. To make sure the system is operating as planned, high-level modules are tested first, followed by low-level modules, and lastly, low-level modules are integrated into high-level modules.

Top-Down Integration Testing

  1. Independently tested module.
  2. No, or few drivers are required.
  3. At the aggregate level, it is more dependable and precise.
  4. Easier interface error isolation.
  5. Early on in this, design flaws can be discovered.
  1. Needs a lot of Stubs.
  2. Modules at lower levels receive insufficient testing.
  3. It is challenging to see the test results.
  4. Stub design is challenging.
Mixed or Sandwiched Integration Testing:

A test of mixed integration is also known as a test of sandwiched integration. A mixed integration test combines bottom-up and top-down testing methodologies. Testing cannot begin in a top-down method until the top-level module has been coded and unit tested. Testing can only begin in a bottom-up manner once the lowest-level modules are complete. The top-down and bottom-up approaches’ drawbacks are overcome by the sandwich or mixed approach. Testing for hybrid integration is another name for it. Also utilized in mixed integration testing are stubs and drivers.

Mixed or Sandwiched Integration Testing

  1. For very large projects with numerous smaller tasks, a mixed approach is helpful.
  2. This Sandwich strategy fixes the flaw in the top-down and bottom-up strategies.
  3. Both top-layer tests and bottom-layer tests can be run in parallel.
  1. Because one component uses a top-down method and the other uses a bottom-up approach, mixed integration testing has a very high cost.
  2. Smaller systems with significant module dependencies cannot employ this integration testing.
When Should Integration Testing be Automated?

If one or more of the following conditions are true, you might consider automating your integration tests:

You must repeatedly run the same set of integration tests.

  • The stability of your product allows for test automation. This is because maintaining the tests takes more effort if you automate a product that isn’t stable.
  • Some test cases are simple to run automatically but may need too much work to run manually.
  • You can see a return on investment (ROI) for test automation when you include the cost and labor it would save.
Criteria for Integration Testing’s Entry and Exit

There are entry and exit criteria for the integration testing phase in every software development methodology:

Criteria for Entry
  • Unit-Tested Components and Modules
  • Fixed and closed all high-priority bugs.
  • To successfully code all modules and integrate them.
  • Tests for integration Plans, test cases, and scenarios approved and recorded.
  • Setting up the necessary test environment for integration plans, test cases, and scenario approval and documentation is required.
  • Integrity testing requires the setup of the necessary test environment.
Exit Criteria
  • Successful integration testing of the application.
  • Test Cases that have been run are recorded
  • Release notes must be submitted once all high-priority problems have been repaired and closed.
Integration Testing Tools

There are several tools available for this testing. Given below is a list of tools:

  • Rational Integration Tester
  • Protractor
  • Steam
Example of Integration Testing

Software testing called “integration testing” focuses on examining how various parts or modules of a system interact with one another to make sure they function properly as a whole. To help you better understand the concept, below is an illustration of integration testing:

Consider that you are developing a web application that consists of a number of modules, such as a user authentication module, a database module, and a payment gateway module. In this scenario, integration testing would examine how these components interact and make sure they work properly together.

Test Case: User Registration

Test Scenario: Confirm that a user can sign up and successfully store their data in the database. Steps for the test:

  1. By providing accurate user information (such as username, password, and email address) in the registration form, you can simulate user registration.
  2. Check that the user information is correctly recorded in the database after submitting the registration form.
  3. Check to see if the user receives an email or message confirming successful registration.
  4. Verify that the user’s registered login credentials are now valid for login.
Test Case: User Login

Test Scenario: Verify that a registered user can log in successfully in this test scenario. Steps for the test:

  1. By providing the registered username and password, you can simulate a user login.
  2. Check to see if the user was successfully authenticated after submitting the login form.
  3. Check to see if the user is brought to the right page after logging in successfully.
  4. Make sure that if incorrect login information is entered, an error message is shown.
Test Case: Processing Payments

Test Scenario: Verify the payment gateway module’s accuracy in processing payments in this test scenario. Steps for the test:

  1. By adding legitimate payment information (such as credit card number, expiration date, and CVV), you can simulate a user making a payment.
  2. Check to see if the payment was received successfully after submitting the payment form.
  3. Check to see if the user receives a message or email confirming a successful transaction.
  4. Verify that the proper measures are taken, such as updating the user’s payment history or notifying the necessary parties, to ensure that they are carried out.
What are the Advantages of Integration Testing?

In software development, integration testing has many benefits. Here are some crucial details:

  1. Early Issue Detection: Integration testing assists in locating errors and problems early on in the development cycle, avoiding them from developing into significant issues at a later time.
  2. System Reliability: It makes sure that the software’s many parts work together without a hitch, resulting in a more dependable and durable system.
  3. Interoperability: Integration testing ensures that different modules, subsystems, or external systems are compatible and operate without interruption in order for them to efficiently cooperate.
  4. Error Localization: It makes troubleshooting and debugging easier by assisting in detecting problems or malfunctions that may happen as a result of the interaction between several modules.
  5. Integration testing assesses system performance under realistic circumstances, spotting any bottlenecks, resource limitations, or performance problems early on.
What are the Disadvantages of Integration Testing?

Despite its advantages, integration testing has several drawbacks that might slow down the development process. Here are some significant points emphasizing the negatives:

  1. Complexity: As the number of components or modules involved increases, integration testing gets complex, making it challenging to pinpoint the core cause of problems.
  2. Time-Consuming: Planning, designing, and carrying out integration tests take a lot of time and effort, especially when there are many dependencies between components.
  3. Dependencies and Stability: Integration testing is difficult to do when some dependent components are unavailable or insufficient since it depends on the stability and availability of all dependent components.
  4. Defect identification and isolation in an integrated environment can be more difficult than in unit testing because several components may be involved.
  5. Cost: Integration testing frequently calls for extra equipment, software, and testing environments, which drives up both the time and financial costs.
What is the Difference Between Integration Testing and System Testing?

Integration testing runs unit tests on one or a few integrated modules to verify if the integrated modules work as designed or not. On the other hand, system testing tests the entire system, seeing if the system works in harmony with all the integrated modules and components.

Integration Testing Techniques 

Integration Testing can be conducted using any testing technique (Blackbox, Whitebox, and Greybox). Some of them are listed below:

Black Box Testing
  • State Transition technique
  • Decision Table Technique
  • Boundary Value Analysis
  • All-pairs Testing
  • Cause and Effect Graph
  • Equivalence Partitioning
  • Error Guessing
White Box Testing
  • Data flow testing
  • Control Flow Testing
  • Branch Coverage Testing
  • Decision Coverage Testing

In the next article, I am going to discuss System Testing in SDLC. Here, in this article, I try to explain Integration Testing in SDLC. I hope you enjoy this Integration Testing in SDLC article.

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