Software Testing

Introduction

Definition

• Software testing is the process of evaluating a software application or system to identify and report defects, bugs, and errors that may affect its functionality, performance, and user experience. 
• Software testing is a critical process in the software development life cycle to evaluate software to meet the requirements and perform as expected, as it helps to ensure that the software is of high quality and meets the needs of its users.

Objectives

• The goal of software testing is to find defects, bugs, and other issues that could impact the quality, reliability, usability, and performance of the software.

Steps of Software Testing

The process of software testing typically involves the following steps:

1. 1. Test planning: In this step, the testing team identifies the testing objectives, scope, and approach, and creates a test plan.
   2. Test case development: The testing team develops test cases based on the requirements and specifications of the software.
   3. Test execution: In this step, the testing team executes the test cases and records the results.
   4. Defect tracking and reporting: Any defects, bugs, or issues identified during testing are tracked and reported to the development team for resolution.
   5. Test closure: After all the tests have been executed, the testing team evaluates the test results and prepares a test closure report.

Types of Software Testing

• Software testing involves different types of testing, such as –

  • White Box Testing/Structural Testing/Clear Box Testing/Glass Box Testing

• • Black Box Testing

    • Black box testing is also one of the most important software testing techniques in which the tester examines the behavior and functionality of a software application without knowing its internal workings.
    • The tester focuses solely on the inputs and outputs of the software, without any knowledge of the underlying code or design.
    • In other words, the tester does not have access to the source code or the internal structure of the application, or any other technical details of the software being tested. Instead, they rely on the software’s documentation, specifications, and requirements to design and execute test cases.
    • During black box testing, the tester will use the software just like an end-user would, without knowing how the software was built. The tester will input data into the software and observe the output or response of the software.
    • The goal of black box testing is to find any defects or issues with the software’s functionality, such as incorrect or unexpected behavior, incorrect outputs, or security vulnerabilities.
    • Black box testing is valuable because it can uncover defects that are not related to the software’s implementation, but rather how the software interacts with the user or the environment.
    • Additionally, black box testing is helpful in ensuring that the software meets its requirements and functions as intended, regardless of how it was built.
    • The advantages of black box testing are that it does not require knowledge of programming languages, and it can uncover defects that may be missed in white box testing, which examines the internal workings of the software. However, it may not uncover all defects, and it can be time-consuming to design and execute test cases.

  • Usability testing

    • Usability testing is a type of software testing that evaluates the user-friendliness of an application or system.
    • The goal of usability testing is to assess how easy and efficient it is for users to accomplish specific tasks within the software.
    • The testers observe and collect feedback from the users as they navigate through the application, identifying any areas where the user experience could be improved.
    • Usability testing can be conducted in person, remotely, or with automated tools.
    • Usability testing is crucial because it helps to identify usability issues that can impact user satisfaction, productivity, and overall software quality. 
    • Overall, Usability testing is an essential part of software testing because it provides valuable insights into the user experience and helps to ensure that the software is user-friendly and easy to use. By prioritizing usability testing, software developers can deliver high-quality software that meets the needs and expectations of their users.

  • Compatibility testing.

    • Compatibility testing is a type of software testing that evaluates whether an application or system can operate effectively across different environments, platforms, browsers, devices, and networks.
    • The goal of compatibility testing is to ensure that the software functions correctly and consistently in all of the intended environments.
    • This type of testing involves testing the software under various scenarios, configurations, and conditions to identify any compatibility issues that may arise. Testers perform compatibility testing by installing and running the software on different operating systems, browsers, and devices, and verifying that it works as expected on each one.
    • Compatibility testing is essential because software is developed for a wide range of environments, and it must work consistently across all of them to meet the needs of users.
    • Without proper compatibility testing, users may experience issues such as crashes, errors, and poor performance, leading to frustration and loss of business.
    • Overall, compatibility testing helps to ensure that the software meets the needs of all users and functions correctly across all environments, which is essential for delivering high-quality software.

• All testing is carried out using various techniques, including manual, automated, and exploratory testing.

Levels of Software Testing

There are several types of Levels of software testing, including:

• Unit Testing

  • Unit Testing is a type of software testing in which individual units or components or small parts of a program/software (called units) are tested separately to check whether they work correctly.
  • In unit testing, each function, method, or module is tested independently from other parts of the system.
  • It is usually performed by developers during the coding phase.
  • The main purpose of unit testing is to find and fix errors at an early stage of development and ensure that each unit performs as expected.

• Module Testing

  • Module testing is an important part of the software development life cycle, and it helps to ensure that software products are reliable, stable, and meet the requirements of end-users.
  • Module testing refers to the process of testing individual software modules or components to ensure that they function correctly in isolation.
  • This is usually done as part of the overall software testing process, which aims to ensure that the software as a whole meets the requirements and specifications.
  • Module testing typically involves creating test cases that exercise the module’s functionality and ensure that it produces the expected output for a given set of inputs. The tests may be automated or performed manually, depending on the complexity of the module and the testing requirements.
  • The goal of module testing is to identify and fix defects or bugs in the individual modules before they are integrated into the larger software system.
  • This helps to reduce the time and effort required for debugging and maintenance later in the development process.

• Integration Testing:

  • Integration testing is a type of software testing in which two or more different but related software modules are combined and tested together to check whether they work properly as a group.
  • Integration testing defines how different modules of the software interact with each other.
  • After unit testing is completed, integration testing is performed to verify the interaction and data flow between different modules.
  • It helps to identify errors related to the interface, communication, and data exchange between components.
  • The main purpose of integration testing is to ensure that integrated modules function correctly when they are combined into a system.
  • Integration testing can be performed by –
    • Top-Down Integration Testing:
    • Bottom-Up Integration Testing:

• System Testing:

  • This type of testing evaluates the system as a whole, including its functionality, performance, and reliability.
  • System Testing is a type of software testing in which the complete and fully integrated software system is tested as a whole to verify that it meets the specified requirements.
  • In system testing, the entire application is tested in an environment similar to the real working environment.
  • It checks the overall functionality, performance, security, and reliability of the system.
  • The main purpose of system testing is to ensure that the complete system works correctly according to user and business requirements.

• Functional Testing:

  • Functional testing is a type of software testing that evaluates the software’s compliance with the functional requirements and specifications.
  • It involves testing the software’s behavior and features against predefined test cases to ensure that it performs the intended functions correctly.
  • Functional testing involves a series of tests designed to verify that the software works as intended and meets the user’s requirements.
  • This includes tests such as unit testing, integration testing, system testing, and acceptance testing.
    Unit testing involves testing individual code components, while integration testing verifies that multiple components can work together as intended. System testing evaluates the entire system’s functionality, and acceptance testing ensures that the software meets the user’s expectations.
  • Functional testing is essential because it helps to ensure that the software performs as expected and meets the user’s requirements. By identifying and addressing functional issues early in the development process, developers can save time and resources, minimize errors, and deliver high-quality software that meets the user’s needs.
  • Overall, functional testing is a critical part of software testing because it helps to ensure that the software works correctly and performs its intended functions. By prioritizing functional testing, software developers can ensure that their software meets the user’s needs and delivers a positive user experience.

Special Software Testing

1. Acceptance Testing:

• • Acceptance Testing is a type of software testing performed to check whether the software system meets the business requirements and is ready for delivery to the customer.
  • Acceptance testing is performed to ensure that the software meets the requirements and expectations of the end users.
  • It is usually performed by end users, clients, or stakeholders to verify that the system works according to their needs.
  • The main purpose of acceptance testing is to confirm that the software is acceptable for release and real-world use.

2. Regression Testing:

• • Regression Testing is a type of software testing that is performed to ensure that recent code changes, updates, or bug fixes have not affected the existing functionality of the software.
  • Regression testing involves retesting previously tested software after changes have been made to ensure that the changes did not introduce any new issues.
  • In regression testing, previously tested test cases are executed again to verify that the old features are still working correctly.
  • The main purpose of regression testing is to maintain software stability and prevent new changes from introducing new errors.

3. Performance Testing:

• • Performance Testing is a type of software testing that is performed to check how well a software system works in terms of speed, responsiveness, stability, and scalability under a particular workload.
  • Performance testing evaluates software performance under various conditions, such as load, stress, and scalability.
  • Performance testing measures how fast the system responds to user requests, how many users it can handle at the same time, and how stable it remains during heavy usage.
  • The main purpose of performance testing is to ensure that the software performs efficiently and provides a smooth user experience under normal and peak load conditions.

4. Security Testing:

• • Security Testing is a type of software testing that is performed to identify vulnerabilities, threats, and mitigate potential security risks in a software system, and to ensure that data and resources are protected from unauthorized access.
  • Security testing checks whether the system can prevent attacks such as hacking, data theft, and unauthorized data modification.
  • It verifies features like authentication, authorization, data encryption, and data integrity.
  • The main purpose of security testing is to ensure that the software system is safe, secure, and protected from cyber threats.

5. Alpha Testing:

8. Non-incremental Testing:

Test Plan

• A test plan in software engineering is a document that outlines the testing approach, objectives, and strategies for a particular software product or project.
• It defines the scope of testing, the testing methods to be used, the testing environment, the resources needed for testing, and the timelines for testing.
• A good test plan is essential for ensuring that the software product meets the requirements, is of high quality, and is free of defects.
• The following are the main components of a test plan in software engineering:-

• • Introduction: This section provides an overview of the test plan, including the purpose, scope, and objectives.
  • Test Strategy: This section outlines the overall approach to be taken for testing, including the testing methods to be used, the test environment, and the testing resources required.
  • Test Scope: This section defines the scope of the testing effort, including the areas of the software product that will be tested and the types of testing that will be performed.
  • Test objectives: Define the purpose of testing and the expected outcome.
  • Test scope: Define the scope of testing, including what will be tested and what will not be tested.
  • Test environment: Define the hardware, software, and network configurations needed to perform testing.
  • Test strategies: Define the testing strategies that will be used, such as functional testing, performance testing, security testing, etc.
  • Test scenarios: Define the specific scenarios that will be tested and the expected results.
  • Test cases: Define the individual test cases that will be used to test each scenario.
  • Test data: Define the data that will be used for testing, including test inputs and expected outputs.
  • Test schedule: Define the timeline for testing, including start and end dates, as well as any milestones or checkpoints.
  • Test resources: Define the resources needed for testing, including personnel, hardware, software, and any other tools or equipment needed.
  • Test deliverables: Define the expected deliverables from testing, including test reports, defect reports, and any other documentation.

Software Testing Strategies

Verification

• Verification is the process of checking whether the software is being developed according to specified requirements, standards, and design documents.
• Verification is the process of evaluating software during development to ensure that it meets the specified requirements.
• Verification is an essential part of software testing that ensures software is developed correctly according to requirements and design specifications.

  It is a preventive approach that improves quality, reduces cost, and ensures reliable software development.
• It is a static process that does not involve executing the program, i.e., it is completed before/without executing the code.
• It answers the question, “Are we building the product right?”
• It focuses on documents and design.
• It includes reviews, inspections, and static analysis.
• This process is performed during the development phase.
• This process detects defects early.
• This process ensures compliance with requirements.
• This process improves and maintains software quality standards.
• It reduces development and maintenance costs.
• This process finds errors early.
• This process reduces the cost of fixing bugs.
• This process improves documentation quality.
• This process ensures proper software development.
• It ensures correctness before moving to the next development phase.
• It improves the reliability of software.
• Verification is performed at each phase of software development:-
  • Requirement Phase → Requirement verification
  • Design Phase → Design verification
  • Coding Phase → Code verification

Validation

Software Quality

Software Quality Models(SQM)

Software Quality Control(SQC)

Software Quality Assurance (SQA)

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