Software Testing Overview

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Questions and Answers

What is the primary focus of system testing?

User interface design quality

Integration and interaction between components (correct)

Correctness of individual components

Documentation completeness

Which of the following best describes the nature of system testing?

It only tests newly developed components.

It is a collective process that may involve a separate testing team. (correct)

It is limited to performance testing of a system.

It is usually performed by individual developers.

What role do use-cases play in system testing?

They identify only the components that need testing.

They facilitate the testing of interactions between multiple components. (correct)

They represent individual component test cases.

They provide documentation for user interface guidelines.

Which of the following is NOT a typical testing policy?

Ensuring all performance benchmarks are met Signup and view all the answers

How does test-driven development (TDD) influence the code development process?

Tests are the primary drivers of code development, written before coding. Signup and view all the answers

What is a limitation of exhaustive system testing?

It is time-consuming and often impractical. Signup and view all the answers

Which of the following statements about system testing is true?

It tests the complete integrated system. Signup and view all the answers

During system testing, what is typically tested?

Interactions between integrated components Signup and view all the answers

What is the primary requirement before moving on to the next increment in test-driven development?

All related tests must pass successfully. Signup and view all the answers

Which of the following is a benefit of test-driven development?

Every code segment has associated tests. Signup and view all the answers

What does regression testing primarily check for?

To ensure changes haven't broken existing code. Signup and view all the answers

What is the main objective of release testing?

To convince the supplier that the system is ready for deployment. Signup and view all the answers

In what way is simplified debugging a benefit of test-driven development?

A failed test directly indicates the area of code needing modification. Signup and view all the answers

How does automated testing simplify regression testing?

By enabling all tests to be re-run easily after changes. Signup and view all the answers

What does the term 'increment of functionality' refer to in test-driven development?

A small, manageable unit of code to be developed. Signup and view all the answers

Which best describes how tests function as system documentation in test-driven development?

Tests detail what the code should do effectively. Signup and view all the answers

What is the primary purpose of using partition testing?

To categorize inputs that yield equivalent outcomes Signup and view all the answers

Which of the following is NOT a part of general testing guidelines?

Select inputs randomly to ensure comprehensive coverage Signup and view all the answers

Which testing type focuses on testing individual objects and methods?

Unit testing Signup and view all the answers

What is a key limitation of testing in software development?

It cannot guarantee the absence of any remaining faults Signup and view all the answers

In guideline-based testing, test cases are chosen based on?

Experience of common programmer errors Signup and view all the answers

What should be done when conducting testing of sequences?

Include sequences of various lengths, including zero Signup and view all the answers

What role does system testing play in software development?

Validates a partial or complete system's functionality Signup and view all the answers

When testing components, which input should especially be included?

Abnormal inputs to ensure system stability Signup and view all the answers

Study Notes

Software Testing Lecture Notes

Software testing aims to demonstrate a program's functionality and identify defects before deployment.
Testing involves executing the program with sample data and checking results for errors, anomalies, or issues with non-functional attributes.
Tests reveal the presence of errors, but not their absence.
Testing is a part of a broader verification and validation process, also including static validation techniques.

Program Testing Goals

Demonstrate to the developer and customer that the software meets its requirements.
- Custom software requires at least one test for each requirement.
- Generic software requires tests for all features and their combinations.
Discover situations where the software's behaviour is incorrect, undesirable, or doesn't conform to its specification.
- Defect testing concentrates on finding undesirable system behaviour (e.g., crashes, incorrect computations, data corruption).

Validation and Defect Testing

Validation testing ensures the system performs correctly for its expected use cases.
Defect testing focuses on identifying defects, potentially using obscure test cases, not necessarily reflecting normal use.

Testing Process Goals

Validation testing ensures the software meets its requirements and functions as intended.
Defect testing aims to find faults or defects in the software where its behaviour is not compliant with the specifications.

Input-Output Model of Program Testing

Input data is processed by the system, which produces output results.
Anomalous behavior in the system is identified via outputs, revealing defects.

Verification vs Validation

Verification asks: "Are we building the product right?". The software must comply with the specification.
Validation asks: "Are we building the right product?". The software must do what the user needs.

V&V Confidence

The aim of verification and validation (V&V) is to establish confidence that the system is fit for purpose.
Confidence depends on the system's purpose, user expectations, and the marketing environment.
- Critical software for an organization requires higher confidence levels.
- Users may have low expectations for certain software types.
- Faster market entry may override thorough defect detection.

Inspections and Testing

Software inspections analyze static system representations (e.g., requirements, design, code) to uncover problems.
Inspections may use tools to help identify defects.
Software testing evaluates a system by executing it with test data to observe its behavior.

Advantages of Inspections

Testing can mask some errors.
Static analysis avoids the need to handle intricate interactions amongst various error points.
Incomplete versions can be inspected without extra costs.
Inspections can identify quality attributes like compliance, portability, and maintainability.

Inspections and Testing - Complementary

Inspections and testing supplement each other, not oppose each other.
Both should be part of the V&V process.
Inspections check conformance to specifications, but not necessarily customer needs.
Inspections do not cover non-functional characteristics (like performance, or usability).

Software Testing Process Model

A systematic model defines and describes the steps for implementing testing on a system.
- Design tests.
- Prepare tests cases data.
- Execute the tests against the system.
- Compare results.
- Prepare test reports

Stages of Testing

Development testing: Involves testing during development to find and fix bugs.
Release testing: A team independent from development tests a complete system (before release).
User testing: Users test the system in a real, end-user environment.

Development Testing

Primarily addresses the specific units and objects within a system, ensuring they function at the unit level.
- Unit testing: Individual program units or object classes are tested; focuses on object functionality.
- Component testing: Individual units are integrated to create composite components; focuses on component interfaces.
- System testing: All components are integrated ensuring interactions work properly.

Unit Testing

Tests individual components in isolation.
A defect-detection process.
Units include functions, methods within an object, whole object classes, and composite components with defined interfaces to access their functionality.

Object Class Testing

Comprehensive test coverage needs testing all object operations, attributes and states.
Inheritance complexities can impact the ability to localize information necessary for thorough test design.

Weather Station Object Interface

Illustrates the methods and attributes of a weather station object (e.g., reportWeather, remoteControl).

Weather Station Testing

Test cases should cover actions like reportWeather, calibrate, test, start-up, and shutdown.
State models can help identify transition sequences and the corresponding events.

Automated Testing

Unit testing should be automated to streamline the process.
Utilize test automation frameworks (e.g., JUnit) to automate writing and running tests.
Frameworks often provide generic test classes that can be extended to create specific test cases, and often display results graphically.

Automated Test Components

Setup: Initializes the system with inputs and expected outputs for a test case.
Call: Executes the unit (e.g., object or method) under test.
Assertion: Compares the result with the expected output.

Unit Test Effectiveness

Test cases should demonstrate expected component behavior.
Tests should expose defects by revealing errors in component behaviour.
- Tests reflecting normal operations and those based on experience of common problems.

Testing Strategies

Partition testing: Groups inputs for similar processing.
Guideline-based testing: Uses testing guidelines to select specific test cases and to identify typical programmer errors.

Partition Testing

Groups data with similar behavior or attributes together.
- The data groups are referred to as equivalence partitions.

Equivalence Partitioning

Divides input/output values into partitions, where similar behavior for each member is anticipated.
Tests need to be chosen from each partition.

Testing Guidelines (sequences)

Test with sequences of varying size.
Test with sequences with specific elements that need access (like start, middle, end).
Test with empty (zero-length) sequences.

General Testing Guidelines

Force various error messages.
Cause input buffers to overflow.
Repeat the same or similar input many times.
Force generation of invalid outputs.
Generate computational results far beyond acceptable ranges.

Key Points

Testing demonstrates error presence but doesn't prove absence of all errors.
Responsibility of testing a system belongs to a group/team separate to development.
Testing includes unit testing, component testing, and system testing.

Release Testing

A testing process for a system released outside the development team.
A critical aim is to prove sufficient quality for actual use.
Usually a black-box testing process (derived from system specifications).

Release testing and System testing

Release testing is a form of system testing.
An independent testing team is often employed for release testing.
Distinct from system testing, release testing emphasizes validation to ensure the system's readiness for external clients.

Requirements Based Testing

Software testing aligned with specific requirements.
Examples:
- Allergy warnings in medical software systems.

Requirements Tests

Specific tests related to each specific requirement.
- Testing examples with patient allergy information.

Features Tested by Scenarios

A set of planned scenarios for actual use.
Testing for specific functionality.

A Usage Scenario

Example showing practical use and testing aspects across system components.
- Practical example covering user actions and system responses for various scenarios.

Performance Testing

Assessing the performance and reliability of the system.
Tests should reflect expected system usage profiles.

Stress Testing

System overload to measure its ability to respond.
- Measures the system's behavior during periods of high load.

User Testing

Involves end-users and customers in the testing process.
Crucial stage even when other testing types are complete.
Reflects the variability in user environments with real-world uses and issues.

Types of User Testing

Alpha testing: Users and developers collaborate at the developer's site.
Beta testing: Users receive a release for testing outside a development environment.
Acceptance testing: Customers decide if the system ready for deployment.

The Acceptance Testing Process

Steps of acceptance testing (e.g., defining criteria, tests, results, outcome).

Stages in the Acceptance Testing Process

Listing the steps involved.

Agile Methods and Acceptance Testing

User/customer involvement in development decisions.
Tests are defined and integrated throughout the agile process.

Key Points (Summary)

Identifying the common error patterns.
Using effective testing techniques.
Applying test automation whenever possible.
Test-driven development: Tests written first; code following.
Scenario testing, defining use cases.
Acceptance testing: Validating if the system meets the client's expectations.

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Description

This quiz covers key concepts in software testing, including the goals and methods used to validate software functionality and identify defects. It discusses the importance of executing tests with sample data and the role of defect testing in ensuring software quality. Test your understanding of the verification and validation processes involved in software development.