The collection of testing techniques employed across the software development lifecycle, from unit testing to system testing, is referred to as methodologies. The foundation of the testing process is thought to be choosing a suitable testing methodology.
With the means of security, compatibility, and usability, a software product should be tested by using the proper testing methodology. Let us learn about these Testing Methodologies in detail-
Functional Testing
Black-box testing includes functional testing. No prior knowledge of programming is necessary. Product functionality, or whether the product performs as the client expects, is tested through functional testing.
By supplying the input data and confirming that the output matches the requirements specified in the requirement document, functionality is confirmed. functioning testing examines a product’s usability, such as how user-friendly an application or product is, as well as its functioning.
Types of Functional Testing:
- Unit Testing
- Integration Testing
- System Testing
- Acceptance Testing
Testing is performed in the below order:
Unit Testing
Testing a product’s distinct components is known as unit testing. The developer is the one conducting this testing. Only developers create unit test cases prior to test execution. Completing all of the unit test cases is crucial since it aids in the early detection of defects.
Furthermore, failure to identify the error during unit testing may result in major and critical problems later on, which would be expensive and take longer to remedy than anticipated.
While doing unit testing if the developer integrates two components to test to save time and the other component is not yet ready, then the developer uses stubs or drivers to perform his testing. If a defect occurs on the integrated system, then it becomes difficult to find the module, because of which the issue has occurred.
Thus, testing a component individually is very important.
Stubs and drivers are basically used when one component calls the function from another component that is not yet developed, thus to create the test environment for testing of the unit, stubs and drivers are used by the developers.
Stubs
A stub is a piece of dummy code with simplified behavior that shares the same input parameters as the real module. Stub is utilized when the sub-modules are not constructed because it adheres to a top-down integration methodology.
Example: If there are three modules i.e. module X, module Y, module Z. Module X is developed and it calls a function from module Y & Z but modules Y and Z are under development. In this case, the stub of module Y & Z is created to test module X
Drivers
The bottom-up integration strategy is used by the driver. When the other module needs to be tested and the main module is not yet available, it is utilized. To enable Module Y & Z to call the function from Module X in that scenario, a fake is made for Module X.
Integration Testing
Integration testing is the testing when two or more modules are integrated or merged to test if the product works fine. Modules are integrated in a planned manner as per the integration plan.
Example: The computer which we use has individual components as a Monitor, Screen, Key Board, Mouse. Once the monitor and keyboard are ready, they should be integrated to verify if the output is as expected.
Approaches used in Integration Testing are:
1. Top-Down approach
2. Bottom-up approach
3. Mixed approach
4. Big Bang approach
Top-down approach
The top-level module is created and tested first in top-down integration testing. Sub-modules are then integrated with the top-level module and tested immediately after that. In the event that the module to be integrated is not built and tested, stubs must be used to finish the integration testing with a top-level module.
To test module 2 in integration testing when modules 4 & 5 are not developed, stubs are created to test the same in the top-down approach.
Bottom-up Approach
In the bottom-up approach, sub-modules are developed and tested first and the whole system is tested.
To test Module C, the Driver of module A is created so that function can be called.
Mixed Approach
Combining top-down and bottom-up strategies is known as the mixed approach. Testing in the top-down method can only begin after the unit has been tested and the top modules have been produced.
Similarly, testing using a bottom-up approach can only begin after the bottom components have been produced and tested. This drawback is addressed by the mixed approach, which allows testing to begin at any point after the modules are created.
Big Bang Approach
Every module is merged and tested all at once in the Big Bang method. This method’s disadvantage is that it would be challenging to identify the module generating the issue if one were to be found during testing. The issue will be rectified once the cause is identified, but it will be expensive and time-consuming because the defect was discovered later.
System Testing
In system testing, a system as a whole i.e. a completely developed system is tested to find defects. All the modules are integrated to test as a complete system. Scenarios prepared for system testing are run to find the defects.
All the modules of a product are integrated and tested to verify that the built product is as per the customer requirement. End-to-end testing is performed to cover the complete scenarios.
Acceptance Testing
Once the System testing is complete, the Product is ready to be released to the Production environment. But before deployment, the customer’s acceptance and approval are required. The customer verifies whether the product is all that they wanted or not. For this acceptance testing is done.
Types of Acceptance Testing:
Alpha Testing: Alpha testing is done internally by the members of the company who developed the product. This testing is not performed by the developers and testers who developed and tested the product.
Beta Testing: Beta testing is done by the actual users in the Production environment. Beta version of the application is released in the real environment to get feedback from the users which indeed helps to reduce the chances of failure of the product in the production environment.
User Acceptance Testing: Testing is done at the user end wherein the prepared UAT test cases are executed. Replica of the production environment is created for the customer to perform the user acceptance testing.
Non-Functional Testing
The purpose of non-functional testing is to confirm a product’s non-functional features.For instance, any product’s performance falls under non-functional activity.
Just as crucial as functional testing is non-functional testing. Improper execution may result in significant problems with the final product.
For instance, if additional feature is added to the program without performance testing, it will become too sluggish to use once it goes live, which would negatively impact the user
Types of Non-functional Testing
- Performance Testing
- Load Testing
- Stress Testing
- Volume Testing
- Security Testing
- Usability Testing
- Compatibility Testing
- Installation Testing
- Uninstallation Testing
- Recovery Testing
- Documentation Testing
Performance Testing
Performance testing is done to verify if the system meets the non-functional requirement identified in the SRS document. It verifies how the system behaves and performs like response time, throughput, etc.
There are various types of Performance testing done as given below:
Load Testing
The purpose of load testing is to see how the system reacts to an increase in load. Does it check if the application functions as intended when the load is at its highest?
In essence, until the load hits its threshold, the number of people utilizing the same program simultaneously increases, increasing the pressure on the system continuously.
For instance, if the application takes 30 seconds to respond and there are 1000 users registered in, testing is carried out by growing the site’s user base until it reaches 1000. It confirms that when the load grows, the response time does not increase.
Stress Testing
Stress testing is carried out beyond the system’s capability to determine when it breaks. In order to highlight a product’s capabilities, tests are conducted using illegal or invalid inputs. Increasing the number of users until the application crashes puts more strain on the system.
For instance, if the application takes 30 seconds to respond and there are 1000 users registered in, testing is carried out by growing the site’s user base until it hits the point at which the application malfunctions (more than 1000 users). The product can no longer accommodate the growing number of users.
Volume Testing
Volume testing is done with a huge amount of data to verify the efficiency & response time of the software and also to check for any data loss.
Security Testing
Security testing is one of the important testing methods as security is a crucial aspect of the Product. It is done to verify if the application is secured or not.
Few examples of what is being tested while performing security testing are:
- Security testing verifies that only authorized users should be able to access data.
- Authentication is verified i.e. the user should be able to log in with his credentials. An incorrect username or password should not allow the user to log in.
- Secured and unsecured pages in the application should be verified.
- For financial sites, the session should timeout after a few minutes if no activity is being performed.
Usability Testing
Usability testing involves examining a variety of features, including display screens, messages, navigation, links, and orphan pages.
Compatibility Testing
Compatibility testing verifies whether the application/Product is compatible with all the hardware/software platforms or not. The application should be compatible with all browsers, operating systems, mobile devices.
Example: The application might show all the images perfectly in one browser whereas, in another browser, the images are shown distorted. So, it’s important to verify the application on all the browsers and operating systems that the customer has asked for in his requirement.
Installation Testing
Installation testing is one of the most important testings as Installation is the very first interaction of the user with the product and it’s important that the user does not face difficulty in installing the same.
The software can be installed via CD, Internet, and network location.
Example: If an installation is done through the Internet, then test cases should be included for:
- Bad network speed
- Broken connection.
- Size and approximate time taken.
- Concurrent installation/downloads.
The Installation of Software requires the use of License keys. Thus different types of licensing are:
- Node-Locked
- Floating
- Named User
- Temp/Evaluation Licenses
Uninstallation Testing
Uninstallation testing aims to confirm that all components are removed and that there are no issues when the product is uninstalled.
Testing the uninstallation process guarantees that all DLL files, executables, and data have been deleted. The application is checked in the Add/Remove programs menu and files are manually deleted to confirm that it has been uninstalled.
Recovery Testing
Recovery testing is done to verify that the data is recovered if any fault occurs; application crashes or power goes off. To test the recovery of data, the software is forcefully failed to check if data is recovered successfully. E.g. Printer can be disconnected to check if the system hangs or can be shut down to check data loss.
Documentation Testing
Documentation testing is done to verify that all the technical/maintenance documents exist and are consistent. If the requirement specifies the types of audience for which a specific manual is required, and it is checked for such compliance.
Testing Techniques
Basically, there are 3 testing techniques that are used for testing. They are White Box Testing, Black Box Testing, and Grey Box Testing. Each of the testing techniques is briefed below for your better understanding.
#1) White Box Testing
The white box testing technique is used to examine the program structure and business logic, it validates the code or program of an application. It is also called Clear Box Testing, Glass Box Testing, or Open Box Testing.
White Box Testing Techniques include:
- Statement Coverage: Examines all the programming statements.
- Branch Coverage: Series of running tests to ensure if all the branches are tested.
- Path Coverage: Tests all the possible paths to cover each statement and branch.
#2) Black Box Testing
The Black Box testing method is used to test the functionality of an application based on the requirement specification. Unlike White Box Testing it does not focus on the internal structure/code of the application.
Black Box Techniques include:
- Boundary Value analysis
- Equivalence Partitioning(Equivalence Class Partitioning)
- Decision Tables
- Domain Tests
- State Models
- Exploratory Testing(Requires less preparation and also helps to find the defects quickly).
#3) Grey Box Testing
This method of testing is performed with less information about the internal structure of an application. Generally, this is performed like Black Box Testing only but for some critical areas of application, White Box Testing is used.
Models in SDLC
Selecting proper testing methodologies also incorporates choosing a proper model in SDLC.
The models include:
- Waterfall model
- V model
- Agile model
- Spiral model
- RAD
Let’s have closer look at each Software Development Models with a brief explanation.
#1) Waterfall Model
Winston Royce created the fundamental life cycle model, known as the Waterfall model, in 1970. Multiple stages or processes are represented in this paradigm in a sequential fashion that gradually descends.
When requirements are clear, technology is understood, and the resources with the necessary expertise are accessible, this method works well.
The waterfall model is defined by the following stages:
- Requirement Gathering and Analysis: Capture and analyze all the requirements and make sure whether they are testable or not.
- System Design: Create and document design based on requirement analysis. Define the hardware and software requirements.
- Implementation: Create robust code for components as per the design and integrate them.
- System Testing: Integrated components form a whole system, this phase is performed to ensure whether the system is working as per the requirements, tracking and reporting the testing progress.
- System Deployment: Make sure if the system is stable with zero bugs, all test criteria had been
met, ensure Environment Setup, etc. - System Maintenance: Makes sure if the application is working efficiently as per the requirement with the suitable environment. In case a defect is found then that should be fixed and deployed (updated) in the environment.
Advantages of Waterfall Model:
- Simple and easy to understand.
- Easy to manage as each phase has its own specific deliverables.
- Overlapping of stages is avoided.
- Good for small projects.
Disadvantages of Waterfall Model:
- Increase in the amount of risk and uncertainty.
- Once entered into the Testing phase, cannot change anything in the previous stages e.g Design and Coding, etc.
- Not good for complex and large projects.
- Not suitable where the requirements keep changing.
#2) V Model
The V Model, sometimes referred to as the Verification and Validation Model, is an extension of the Waterfall Model in which the process execution occurs in a sequential fashion in V-Shape. With this method, each stage of the development cycle includes a testing phase that is directly related to it.
Because testing is done at every stage of development rather than at the conclusion, it has been shown to be more advantageous and economical than the waterfall model.
V Model is classified into 3 Phases.
- Verification Phase
- Coding Phase
- Validation Phase
a) Verification Phase:
- Business Requirement Analysis: Communicate with the customer to understand their expectations and requirements.
- System Design: Design a complete system and its components along with the hardware and software requirements.
- Architectural Design: In this phase architectural specifications are captured. This is also known as high-level Design.
- Module Design: This is also known as Low-Level Design, Detailed internal design for all the specified system modules.
b) Coding Phase:
The actual coding step of the development lifecycle is included in this phase. The system and architectural architecture outlined in the technological platform from the previous step should guide the selection of programming languages.
c) Validation Phase:
- Unit Testing: Performed on an individual module to eliminate the bugs at the early stage.
- Integration Testing: Performed to test the communication between different modules in the system.
- System Testing: System Testing is performed on a system as a whole.
- Acceptance Testing: This is associated with the business requirements. It is performed in a user environment from the user’s point of view.
Advantages of V model
- Simple, easy to use, and understand.
- Overlapping is avoided as phases are executed one at a time.
- Easy to manage and suitable for small projects.
The disadvantages of the V Model are more or less similar to the disadvantages of the Waterfall model.
#3) Agile Model
The Agile Model demonstrates an incremental and iterative methodology. In order to give iterations, this method divides the product into tiny, incremental components. Planning, requirement analysis, design, coding, unit testing, acceptance testing, and other processes are then included in each iteration.
Additionally, this method enables ongoing communication with the client for regular requirement revisions and feedback.
The following image will show the iteration cycle in the Agile Model:
Advantages of the Agile model:
- A realistic approach to software development.
- Promotes teamwork.
- Eliminates mismatch between requirements and test cases.
- Rapid and requires a minimum amount of resources.
- Suitable for large and long-term projects.
- Good for changing requirements.
- Easy to manage.
Disadvantages of the Agile model:
- Not suitable for complex projects.
- Requires a heavy interaction with the customer which may cause delay.
- Misguidance of requirements may cause the incorrect development of the software product.
- Increased maintainability risk.
- Handover to another team may be quite challenging.
#4) Spiral Model
The spiral model incorporates an iterative development approach along with the systematic approach of the waterfall model. It is similar to the incremental model and emphasizes Risk Analysis.
Spiral Model has four stages:
- Planning Phase
- Risk Analysis
- Engineering Phase
- Evaluation Phase
1) Planning Phase: In this phase, the requirements are gathered and reviewed to finalize the test case.
2) Risk Analysis: This stage includes identifying, monitoring, and estimating management risks. Requirements are analyzed to identify the risks using techniques like brainstorming, walkthrough, etc.
3) Engineering Phase: In this phase, the software is developed and tested at the end.
4) Evaluation Phase: This is the last stage where a customer evaluates the output of a project and gives their feedback for either the next spiral or approval.
Pictorial representation of Spiral Model:
When to use the Spiral model:
- For high-risk projects.
- When the requirements are complex.
- If a project is large.
- Have a sufficient amount of time for getting user’s feedback for the next spiral.
- Requires significant changes due to research and exploration.
- Users are not sure of their needs.
Advantages of Spiral Model:
- Avoidance of risk as it involves a high amount of risk analysis.
- Rapid Development.
- Changes in requirements are accommodated easily.
- Requirements can be acquired more accurately.
Disadvantages of the Spiral model:
- Complex management.
- Not suitable for small projects.
- May involve no. of spirals(indefinite).
- Costly.
- Requires a high amount of risk analysis and expertise for their project’s success.
#5) RAD Model
Rapid Application Development(RAD) is a type of incremental model. In this approach, components are developed in parallel.
This is a rapid approach and it can give a fast product to the customer to provide feedback.
Phases in RAD are as follows:
- Business Modeling: Identifies vital information and its flow between various business channels.
- Data Modeling: Information gathered in the previous stage is used to define data objects required for the business.
- Process modeling: Data objects are converted to get business objectives and flow of information.
- Application Generation: In this phase, automation tools are used to convert the process model into actual code.
- Testing and Turnover: Tests all the components of a system, hence overall testing time is reduced.
Advantages of RAD Model:
- Progress can be measured.
- Reduces development time.
- Increased reusability.
- Quick initial reviews.
- Enhances customer feedback.
Disadvantages of RAD Model:
- Requires high skilled resources.
- High-cost estimation.
- Not applicable for cheaper projects.
- High dependency on modeling skills.
- Only a modularized system can be built using RAD.
Difference Between Software Testing Methodologies And Strategies
The answer to this is not much complex as there is a simple difference between both.
The techniques or approaches to testing that involve unit testing through system testing are known as testing methodologies.
The project manager, a group of developers, and testers should all take into account testing strategies, which provide a summary of the main problems that arise during the testing process.
Conclusion
Application testing is guided by software testing approaches to ensure that the final product meets client expectations. They guarantee that every aspect of a product or application satisfies the needs of the client.
The action or series of acts at the heart of the testing process is selecting an appropriate testing methodology. This could potentially be a flexible activity that adapts to the software product’s timeframe and company needs.
To have a more adaptable and effective final product that meets the demands and expectations of the client in the allotted period, one can, nevertheless, select one or even several software testing methodologies.
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