U3

Page 1: Levels of Testing

Overview of Testing Levels

  • Need for Levels of Testing: Execution-based software testing is essential for large systems, typically carried out in 3-4 major phases:

    • Unit Test

    • Integration Test

    • System Test

    • Acceptance Test

Unit Testing

  • Definition: Testing a single component.

  • Goal: Detect functional and structural defects within the unit.

Integration Testing

  • Definition: Testing several components as a group.

  • Goal: Investigate interactions among the components.

System Testing

  • Definition: Testing the entire system as a whole.

  • Goal: Evaluate usability, reliability, and performance.

Acceptance Testing

  • Definition: Developers demonstrate that the software meets all client requirements.

  • Goal: Gain client recommendation letters.

Page 2: System Development Approaches

Development Approaches

  • Bottom-Up Approach: Testing starts from the lowest level of modules.

  • Top-Down Approach: Testing begins at the highest level of the module hierarchy.

Programming Languages

  • Procedure-Oriented Languages: Focus on passive data and active procedures. Tests aim to generate input data for procedures.

  • Object-Oriented Languages: Composed of active data and encapsulated operations. Testing involves designing call orders to access various operations.

Levels of Abstraction

  • Procedural Systems: Levels include functions, subsystems, and complete systems.

  • Object-Oriented Systems: Levels include methods, classes, clusters of classes, and the entire system.

Unit Testing Characteristics

  • Definition of a unit in procedural vs. object-oriented systems.

Page 3: Components Suitable for Unit Test

Advantages of Unit Testing

  • Easier to design, execute, record, and analyze test results.

  • Easier to locate and repair defects.

Preparation for Unit Tests

  • General approach planning.

  • Designing test cases and procedures.

  • Defining relationships between tests.

  • Preparing auxiliary code.

Unit Test Planning

  • Preparation Process:

    • Phase 1: Describe the unit test approach and risks.

    • Phase 2: Identify features to be tested.

    • Phase 3: Add levels of detail.

Page 4: Detailed Unit Test Planning

Phase 1: Approach and Risks

  • Outline the unit testing approach.

  • Identify risks and test requirements.

  • Define completeness and termination conditions.

Phase 2: Feature Identification

  • Determine which features will be tested based on specifications.

  • Assess risks of not testing certain features.

Phase 3: Detail Addition

  • Refine resource and scheduling portions of the unit test plan.

  • Include descriptions of test result recording.

Page 5: Designing Unit Tests

Test Case Design

  • Importance of specifying test cases (i) the test cases and (ii) test procedures.

  • Use black and white box test design strategies.

  • Focus on method interactions in class testing as opposed to procedures in procedural testing.

Issues in Class Testing

  1. Adequate feature testing.

  2. Observing state transitions.

  3. Retesting implications for class modifications.

Page 6: Test Harness

Definition

  • Auxiliary code developed to support testing.

  • Components of Test Harness: Drivers and stubs.

Functionality of Test Harness

  • Drivers: Call target units and pass input parameters.

  • Stubs: Represent called modules and display messages.

Importance of Test Harness

  • Complexity of harness dependent on code's nature.

Page 7: Running Unit Tests

Execution Criteria

  • Begins when units are available, test cases are designed, and test harness is prepared.

Recording Results

  • Use test logs to capture results and summarize test efforts (pass/fail).

  • Document reasons for failures.

Page 8: Integration Testing Goals

Main Goals of Integration Tests

  • Detect defects at the interface of units.

  • Assemble units into working subsystems and ultimately the entire system.

Integration Strategies for Procedural Systems

  • Bottom-Up Integration: Starts with lowest level modules.

  • Top-Down Integration: Begins from the top of the module hierarchy.

Page 9: Designing Integration Tests

Designing Procedures

  • Apply black or white box design strategies focusing on parameter pairs and calling relationships.

  • Generate test data for data and control flows.

Integration Test Planning

  • Combine all units, creating a plan based on relevant documentation: system architecture, requirements, etc.

Page 10: Scenario Testing

Definition

  • A testing technique that utilizes real-world scenarios to evaluate system behavior through credible and easy-to-evaluate scenarios.

Methods in Scenario Testing

  • System scenarios, use-case scenarios, and role-based scenarios.

Risks of Scenario Testing

  • Complication from product instability and lack of test coverage.

Page 11: System Testing Overview

Definition and Types

  • Goal: Verify system performance according to requirements.

  • Types include functional, performance, stress, configuration, security, and recovery testing.

Page 12: Performance Testing

Objectives

  • Ensure compliance with functional and quality (e.g., performance) requirements.

  • Evaluate resource allocation and performance impact factors.

Page 13: Stress Testing

Description

  • Testing under maximum resource load to identify breaking points or crashes in the system.

Page 14: Configuration Testing

Objectives

  • Evaluate system performance during hardware changes or reconfigurations.

Page 15: Internationalization Testing

Purpose

  • Verify the software can be adapted for various languages and regions.

Page 16: Ad-hoc Testing

Definition

  • Informal testing without structured planning, usually done after formal tests.

Page 17: Alpha, Beta and Acceptance Tests

Definitions

  • Alpha tests at developer’s site; beta tests in real-world conditions.

  • Acceptance tests validate that software meets user requirements before deployment.

Page 18: Object-Oriented Systems Testing

Levels of OO Testing

  1. Unit Testing

  2. Subsystem Testing

  3. System Testing

Techniques

  • Grey box testing and other techniques focused on classes and methods.

Page 19: Usability and Accessibility Testing

Usability Testing Principles

  • Seven key traits of good UI including correctness, intuitiveness, consistency, and usefulness.

Accessibility Features

  • Importance of providing UI accessibility for disabled users.

Page 20: Configuration Testing

Overview

  • Process of checking the software operation across various hardware configurations and ensuring its compatibility.

Page 21: Compatibility Testing

Definition

  • Ensuring software interacts correctly with other software and specifies system requirements.

Page 22: Web Site Testing

Areas of Focus

  • Configuration, compatibility, usability, documentation, and localization testing specific to web pages and applications.

Page 23: Testing Documentation

Type and Importance

  • Documentation checks improve usability, reliability, and lower support costs.

Page 24: Correctness in Documentation

Importance of Testing Documentation

  • Treat documentation like software to find bugs in both.

Page 25: Documentation Testing Checklist

Areas to Cover

  • Technical accuracy, completeness, and running checks for errors.

Page 26: Best Practices in Documentation Testing

Recommendations

  • Follow user steps, examine figures, and test examples thoroughly.

Page 27: Summary

Key Takeaways

  • Each testing phase is vital for successful software development and must be approached systematically to ensure quality.