This document discusses definitions, principles, and best practices of test-driven development (TDD). It defines different types of TDD like test-oriented development, test-driven design, acceptance TDD, and developer TDD. The key principles of TDD discussed are red-green-refactor cycles, writing tests before code, and values like improved design, code quality, and maintenance. Guidelines around trustworthy, maintainable and readable unit tests are also provided.
The document discusses test-driven development (TDD). TDD involves writing tests before writing code to specify desired functionality, then writing just enough code to pass each test. This process of red-green-refactor evolves the system design through tests. TDD results in decoupled, well-designed code and provides benefits like confidence, documentation, and safe refactoring. The document also provides tips for writing better tests, such as keeping tests small, expressive, isolated, and automated.
Software quality is critical to consistently and continually delivering new features to our users. This talk covers the importance of software quality and how to deliver it via unit testing, Test Driven Development and clean code in general.
This is the deck from a talk I gave at Desert Code Camp 2013.
This document provides an overview of test-driven development (TDD). TDD involves writing tests before writing code to ensure new functionality works as intended. Key principles of TDD include writing failing tests first, then code to pass the tests, and refactoring code while maintaining all tests. TDD results in higher quality, flexible, readable and maintainable code. It also helps improve both internal code quality and external functionality through a well-designed development process focused on automated testing.
Getting started with Test Driven Development - Ferdous Mahmud ShaonCefalo
Getting Started with TDD discusses test-driven development (TDD). TDD involves writing unit tests before writing code to make the tests pass. This ensures code is testable and bugs are prevented. The document outlines the basic TDD process of writing a failing test, then the minimum code to pass it, and refactoring the code without breaking tests. Uncle Bob's three laws of TDD state you must write a failing test first before code, only code to pass the test, and refactor without breaking tests. Benefits of TDD include cleaner code, testability, reduced bugs, and safer refactoring. The document provides an example of building a simple calculator using TDD.
The document discusses unit testing and provides guidance on how to effectively implement unit testing. It defines unit testing as testing individual units or components of software code to verify they are functioning as intended. The document outlines best practices for unit testing such as writing test cases that cover valid, invalid, and boundary conditions. It also recommends testing frameworks like JUnit that can automate running test cases. Overall, the document advocates for developing a rigorous unit testing strategy and practicing habits like writing tests first and continuously running tests to improve code quality.
This document provides an overview of unit testing and isolation frameworks. It defines key concepts like units, unit tests, stubs, mocks and isolation frameworks. It explains that the goal of unit tests is to test individual units of code in isolation by replacing dependencies with stubs or mocks. It also discusses different isolation frameworks like Rhino Mocks and Moq that make it easier to dynamically create stubs and mocks without writing implementation code. The document covers different styles of isolation like record-and-replay and arrange-act-assert. It emphasizes best practices like having one mock per test and using stubs for other dependencies being tested.
This document provides an overview of test-driven development (TDD). It defines TDD as a technique for building software where tests are written before code to guide development. The key aspects of TDD covered are:
- Writing tests first before code, which helps improve design and ensures tests are written.
- The TDD mantra of Red-Green-Refactor, where tests initially fail (Red), code is written to pass tests (Green), then code is refactored to improve design.
- An example case study of a large Java project developed using TDD that has over 20,000 lines of unit tests providing over 90% test coverage.
Unit testing basics with NUnit and Visual StudioAmit Choudhary
Unit testing in .NET provides several benefits such as encouraging better design, serving as documentation, and providing a safety net for refactoring. There are different types of tests like unit, integration, user acceptance, and test-driven development tests. A unit test invokes a method or class and checks assumptions about its logical behavior. Unit tests exercise single units of code while integration tests exercise how units work together. Tests should target logical code with decisions. Good tests are automated, easy to implement, run quickly, and can be run by anyone at any time. The document outlines guidelines for creating test projects, classes, and methods along with .NET testing frameworks, techniques like mocking and dependency injection, code coverage, and qualities of trust
The document discusses test-driven development (TDD). TDD involves writing tests before writing code to specify desired functionality, then writing just enough code to pass each test. This process of red-green-refactor evolves the system design through tests. TDD results in decoupled, well-designed code and provides benefits like confidence, documentation, and safe refactoring. The document also provides tips for writing better tests, such as keeping tests small, expressive, isolated, and automated.
Software quality is critical to consistently and continually delivering new features to our users. This talk covers the importance of software quality and how to deliver it via unit testing, Test Driven Development and clean code in general.
This is the deck from a talk I gave at Desert Code Camp 2013.
This document provides an overview of test-driven development (TDD). TDD involves writing tests before writing code to ensure new functionality works as intended. Key principles of TDD include writing failing tests first, then code to pass the tests, and refactoring code while maintaining all tests. TDD results in higher quality, flexible, readable and maintainable code. It also helps improve both internal code quality and external functionality through a well-designed development process focused on automated testing.
Getting started with Test Driven Development - Ferdous Mahmud ShaonCefalo
Getting Started with TDD discusses test-driven development (TDD). TDD involves writing unit tests before writing code to make the tests pass. This ensures code is testable and bugs are prevented. The document outlines the basic TDD process of writing a failing test, then the minimum code to pass it, and refactoring the code without breaking tests. Uncle Bob's three laws of TDD state you must write a failing test first before code, only code to pass the test, and refactor without breaking tests. Benefits of TDD include cleaner code, testability, reduced bugs, and safer refactoring. The document provides an example of building a simple calculator using TDD.
The document discusses unit testing and provides guidance on how to effectively implement unit testing. It defines unit testing as testing individual units or components of software code to verify they are functioning as intended. The document outlines best practices for unit testing such as writing test cases that cover valid, invalid, and boundary conditions. It also recommends testing frameworks like JUnit that can automate running test cases. Overall, the document advocates for developing a rigorous unit testing strategy and practicing habits like writing tests first and continuously running tests to improve code quality.
This document provides an overview of unit testing and isolation frameworks. It defines key concepts like units, unit tests, stubs, mocks and isolation frameworks. It explains that the goal of unit tests is to test individual units of code in isolation by replacing dependencies with stubs or mocks. It also discusses different isolation frameworks like Rhino Mocks and Moq that make it easier to dynamically create stubs and mocks without writing implementation code. The document covers different styles of isolation like record-and-replay and arrange-act-assert. It emphasizes best practices like having one mock per test and using stubs for other dependencies being tested.
This document provides an overview of test-driven development (TDD). It defines TDD as a technique for building software where tests are written before code to guide development. The key aspects of TDD covered are:
- Writing tests first before code, which helps improve design and ensures tests are written.
- The TDD mantra of Red-Green-Refactor, where tests initially fail (Red), code is written to pass tests (Green), then code is refactored to improve design.
- An example case study of a large Java project developed using TDD that has over 20,000 lines of unit tests providing over 90% test coverage.
Unit testing basics with NUnit and Visual StudioAmit Choudhary
Unit testing in .NET provides several benefits such as encouraging better design, serving as documentation, and providing a safety net for refactoring. There are different types of tests like unit, integration, user acceptance, and test-driven development tests. A unit test invokes a method or class and checks assumptions about its logical behavior. Unit tests exercise single units of code while integration tests exercise how units work together. Tests should target logical code with decisions. Good tests are automated, easy to implement, run quickly, and can be run by anyone at any time. The document outlines guidelines for creating test projects, classes, and methods along with .NET testing frameworks, techniques like mocking and dependency injection, code coverage, and qualities of trust
This workshop is designed specially for Queen Mary University of London alumni, in order to teach them TDD.
You will learn: What is TDD, Why and How.
If you want to learn more: https://github.com/MyPitit/TDD
Unit Testing Concepts and Best PracticesDerek Smith
Unit testing involves writing code to test individual units or components of an application to ensure they perform as expected. The document discusses best practices for unit testing including writing atomic, consistent, self-descriptive tests with clear assertions. Tests should be separated by business module and type and not include conditional logic, loops, or exception handling. Production code should be isolated from test code. The goal of unit testing is to validate that code meets specifications and prevents regressions over time.
Roy Osherove on Unit Testing Good Practices and Horrible MistakesRoy Osherove
Roy Osherove provides training courses on topics like test-driven development (TDD), behavior-driven development (BDD), and consulting/coaching services. He discusses test reviews as an alternative to code reviews that can be quicker and help learning teams. The presentation focuses on creating tests that are trustworthy, maintainable, and readable through techniques like avoiding test logic, not repeating production logic, separating unit and integration tests, and using readable structures, naming, and avoiding magic values.
The document discusses testing and mocking with the Moq framework. It covers different types of tests like unit tests, integration tests, and acceptance tests. It also discusses the AAA pattern for arranging, acting, and asserting in tests. The document dives into code dependencies, priorities for testing, and how mocking with Moq can help isolate components for testing. It provides examples of creating mocks with Moq and verifying mock behavior using methods like Returns, Callback, and It.
The document discusses effective unit testing. It covers topics like the value of writing tests, test-driven development, behavior-driven development, test doubles, structuring tests with arrange-act-assert/given-when-then, checking behavior not implementation, test smells, JUnit basics, and parameterized testing. The goal of tests is to validate code behavior, catch mistakes, and shape design. Writing tests also helps learn what the code is intended to do.
Test Driven Development - The art of fearless programmingChamil Jeewantha
Test Driven Development is nothing more than "Unit Testing" but an art of unit testing. Arts require lots of practice.
To start with TDD, it is very important to understand what is unit testing. The common problem many coders have is "Not understanding what is a unit". This presentation targets to solve this basic problem than going behind non-understandable jargons.
Ever tried doing Test First Test Driven Development? Ever failed? TDD is not easy to get right. Here's some practical advice on doing BDD and TDD correctly. This presentation attempts to explain to you why, what, and how you should test, tell you about the FIRST principles of tests, the connections of unit testing and the SOLID principles, writing testable code, test doubles, the AAA of unit testing, and some practical ideas about structuring tests.
The document provides guidelines for writing effective unit tests, including why they are important (ensuring code works as expected, protecting work from accidental breaks, serving as documentation), what should be tested (models, services, commands, utilities), when they should be written (before or after code via test-driven development), and how to write good tests (automated, repeatable, single-purpose, readable, isolated, avoiding duplication).
White box testing involves testing internal coding and infrastructure by executing different lines of code. It is done by developers who have knowledge of the internal structure. Black box testing treats the system as a "black box" and tests it without knowledge of internal structures by validating inputs and outputs. Unit testing validates individual units of source code and is done by developers to ensure each part is correct before integration. Both white box and unit testing can be done earlier and be more thorough than black box testing, but require more skilled testers and knowledge of internal structures. Black box testing can be done by non-technical testers and from an end user perspective.
Unit testing involves writing code to test individual units or components of an application to ensure they operate as expected. Unit tests act as specifications for code and help produce better, more readable and maintainable code. An effective unit test has one test class per code class, runs tests in isolation, has clear and descriptive names from a user perspective, and asserts a single outcome per test. Tools like mocking frameworks can help with unit testing by injecting dependencies and states. Unit tests should focus on testing logic and not user interfaces.
Unit testing is a method to test individual units of source code to determine if they are fit for use. A unit is the smallest testable part of an application. Unit tests are created by programmers during development. Test-driven development uses tests to drive the design by writing a failing test first, then code to pass the test, and refactoring the code. Unit tests should be isolated, repeatable, fast, self-documenting, and use techniques like dependency injection and mocking dependencies. Benefits of unit testing include instant feedback, promoting modularity, acting as a safety net for changes, and providing documentation.
This document provides an introduction to unit testing and mocking. It discusses the benefits of unit testing such as safer refactoring and value that increases over time. It provides a recipe for setting up a unit test project with test classes and methods using AAA syntax. It also covers what mocking is and how to use mocking frameworks to create fake dependencies and check interactions. Resources for learning more about unit testing and related tools are provided.
The document discusses unit testing fundamentals, including definitions of unit testing, benefits of unit testing like fewer bugs, and differences between unit and functional testing. It provides best practices for unit testing like tests running fast and in isolation. The document also covers test-driven development, exposing seams to make code testable, using mocking frameworks, and maintaining good test coverage.
The document discusses assessing unit test quality and describes a project called PEA that aims to collect and report metrics around test directness and assertion density. It outlines various approaches tried for PEA, including static code analysis, bytecode instrumentation, aspect-oriented programming, and using a debugger. The preferred approach ended up being to use the Java Platform Debugger Architecture to monitor tests running in another JVM without modifying code.
Unit testing involves testing individual components of software to ensure they function as intended when isolated from the full system. It helps identify unintended effects of code changes. While unit tests cannot prove the absence of errors, they act as an executable specification for code behavior. Writing unit tests requires designing code for testability through principles like single responsibility and dependency injection. Tests should focus on public interfaces and state transitions, not implementation details. Test-driven development involves writing tests before code to define requirements and ensure only testable code is written. Mocking frameworks simulate dependencies to isolate the system under test. Well-written unit tests keep behaviors isolated, self-contained, and use the arrange-act-assert structure.
This document summarizes unit testing done for core methods using the NUnit testing framework integrated with Jenkins. It discusses the testing framework used, naming conventions for test cases, the Arrange Act Assert pattern for writing test cases, sample test cases, goals of unit testing, and concludes with a demonstration and Q&A. A total of 496 test cases were written to test 6 core methods.
This document provides an overview of unit testing. It defines a unit as a software component containing routines and variables. Unit testing involves testing individual units in isolation to find defects. The benefits of unit testing include refactoring code easily and making integration testing simpler. Various test types are covered, including functional, non-functional, and structure-based testing. Static and white box testing techniques like statement coverage and branch coverage are also discussed. The document concludes with guidelines for effective unit testing.
Unit testing has entered the main stream. It is generally considered best practice to have a high level of unit test code coverage, and to ideally write tests before the code, via Test Driven Development.
However, some code is just plain difficult to test. The cost of effort of adding the tests may seem to outweigh the benefits. In this session, we will do a quick review of the benefits of unit tests, but focus on how to test tricky code, such as that static and private methods, and legacy code in general.
Examples are in Java, but the principals are language agnostic.
Beginners - Get Started With Unit Testing in .NETBaskar K
Beginners - Get started with unit testing in .NET. Introduction to unit testing and mocking.. List of unit testing frameworks available in .NET - NUnit, xUnit.net, Visual Studio unit test framework. List of mocking frameworks available in .NET - Moq, Rhino Mocks, FakeItEasy, NSubstitue, JustMock, and TypeMock. Introduction to Visual Studio Unit Testing Framework, NUnit and xUnit.net.
The process of changing a software system in such a way that it does not alter the external (observable) behavior of the code yet improves its internal structure, to make it easier to understand and cheaper to modify.
The core idea of lean is to eliminate/reduce non-value-added activities (termed "wastes") and thus increase customer value. The Agile itself is a lean for the software development life cycle, and I am sharing a couple of Agile best practices adopted by my teams to make the Scrum methodology more extra lean.
The presentation contains the best agile practices and their benefits in terms of Lean in an agile methodologies
This workshop is designed specially for Queen Mary University of London alumni, in order to teach them TDD.
You will learn: What is TDD, Why and How.
If you want to learn more: https://github.com/MyPitit/TDD
Unit Testing Concepts and Best PracticesDerek Smith
Unit testing involves writing code to test individual units or components of an application to ensure they perform as expected. The document discusses best practices for unit testing including writing atomic, consistent, self-descriptive tests with clear assertions. Tests should be separated by business module and type and not include conditional logic, loops, or exception handling. Production code should be isolated from test code. The goal of unit testing is to validate that code meets specifications and prevents regressions over time.
Roy Osherove on Unit Testing Good Practices and Horrible MistakesRoy Osherove
Roy Osherove provides training courses on topics like test-driven development (TDD), behavior-driven development (BDD), and consulting/coaching services. He discusses test reviews as an alternative to code reviews that can be quicker and help learning teams. The presentation focuses on creating tests that are trustworthy, maintainable, and readable through techniques like avoiding test logic, not repeating production logic, separating unit and integration tests, and using readable structures, naming, and avoiding magic values.
The document discusses testing and mocking with the Moq framework. It covers different types of tests like unit tests, integration tests, and acceptance tests. It also discusses the AAA pattern for arranging, acting, and asserting in tests. The document dives into code dependencies, priorities for testing, and how mocking with Moq can help isolate components for testing. It provides examples of creating mocks with Moq and verifying mock behavior using methods like Returns, Callback, and It.
The document discusses effective unit testing. It covers topics like the value of writing tests, test-driven development, behavior-driven development, test doubles, structuring tests with arrange-act-assert/given-when-then, checking behavior not implementation, test smells, JUnit basics, and parameterized testing. The goal of tests is to validate code behavior, catch mistakes, and shape design. Writing tests also helps learn what the code is intended to do.
Test Driven Development - The art of fearless programmingChamil Jeewantha
Test Driven Development is nothing more than "Unit Testing" but an art of unit testing. Arts require lots of practice.
To start with TDD, it is very important to understand what is unit testing. The common problem many coders have is "Not understanding what is a unit". This presentation targets to solve this basic problem than going behind non-understandable jargons.
Ever tried doing Test First Test Driven Development? Ever failed? TDD is not easy to get right. Here's some practical advice on doing BDD and TDD correctly. This presentation attempts to explain to you why, what, and how you should test, tell you about the FIRST principles of tests, the connections of unit testing and the SOLID principles, writing testable code, test doubles, the AAA of unit testing, and some practical ideas about structuring tests.
The document provides guidelines for writing effective unit tests, including why they are important (ensuring code works as expected, protecting work from accidental breaks, serving as documentation), what should be tested (models, services, commands, utilities), when they should be written (before or after code via test-driven development), and how to write good tests (automated, repeatable, single-purpose, readable, isolated, avoiding duplication).
White box testing involves testing internal coding and infrastructure by executing different lines of code. It is done by developers who have knowledge of the internal structure. Black box testing treats the system as a "black box" and tests it without knowledge of internal structures by validating inputs and outputs. Unit testing validates individual units of source code and is done by developers to ensure each part is correct before integration. Both white box and unit testing can be done earlier and be more thorough than black box testing, but require more skilled testers and knowledge of internal structures. Black box testing can be done by non-technical testers and from an end user perspective.
Unit testing involves writing code to test individual units or components of an application to ensure they operate as expected. Unit tests act as specifications for code and help produce better, more readable and maintainable code. An effective unit test has one test class per code class, runs tests in isolation, has clear and descriptive names from a user perspective, and asserts a single outcome per test. Tools like mocking frameworks can help with unit testing by injecting dependencies and states. Unit tests should focus on testing logic and not user interfaces.
Unit testing is a method to test individual units of source code to determine if they are fit for use. A unit is the smallest testable part of an application. Unit tests are created by programmers during development. Test-driven development uses tests to drive the design by writing a failing test first, then code to pass the test, and refactoring the code. Unit tests should be isolated, repeatable, fast, self-documenting, and use techniques like dependency injection and mocking dependencies. Benefits of unit testing include instant feedback, promoting modularity, acting as a safety net for changes, and providing documentation.
This document provides an introduction to unit testing and mocking. It discusses the benefits of unit testing such as safer refactoring and value that increases over time. It provides a recipe for setting up a unit test project with test classes and methods using AAA syntax. It also covers what mocking is and how to use mocking frameworks to create fake dependencies and check interactions. Resources for learning more about unit testing and related tools are provided.
The document discusses unit testing fundamentals, including definitions of unit testing, benefits of unit testing like fewer bugs, and differences between unit and functional testing. It provides best practices for unit testing like tests running fast and in isolation. The document also covers test-driven development, exposing seams to make code testable, using mocking frameworks, and maintaining good test coverage.
The document discusses assessing unit test quality and describes a project called PEA that aims to collect and report metrics around test directness and assertion density. It outlines various approaches tried for PEA, including static code analysis, bytecode instrumentation, aspect-oriented programming, and using a debugger. The preferred approach ended up being to use the Java Platform Debugger Architecture to monitor tests running in another JVM without modifying code.
Unit testing involves testing individual components of software to ensure they function as intended when isolated from the full system. It helps identify unintended effects of code changes. While unit tests cannot prove the absence of errors, they act as an executable specification for code behavior. Writing unit tests requires designing code for testability through principles like single responsibility and dependency injection. Tests should focus on public interfaces and state transitions, not implementation details. Test-driven development involves writing tests before code to define requirements and ensure only testable code is written. Mocking frameworks simulate dependencies to isolate the system under test. Well-written unit tests keep behaviors isolated, self-contained, and use the arrange-act-assert structure.
This document summarizes unit testing done for core methods using the NUnit testing framework integrated with Jenkins. It discusses the testing framework used, naming conventions for test cases, the Arrange Act Assert pattern for writing test cases, sample test cases, goals of unit testing, and concludes with a demonstration and Q&A. A total of 496 test cases were written to test 6 core methods.
This document provides an overview of unit testing. It defines a unit as a software component containing routines and variables. Unit testing involves testing individual units in isolation to find defects. The benefits of unit testing include refactoring code easily and making integration testing simpler. Various test types are covered, including functional, non-functional, and structure-based testing. Static and white box testing techniques like statement coverage and branch coverage are also discussed. The document concludes with guidelines for effective unit testing.
Unit testing has entered the main stream. It is generally considered best practice to have a high level of unit test code coverage, and to ideally write tests before the code, via Test Driven Development.
However, some code is just plain difficult to test. The cost of effort of adding the tests may seem to outweigh the benefits. In this session, we will do a quick review of the benefits of unit tests, but focus on how to test tricky code, such as that static and private methods, and legacy code in general.
Examples are in Java, but the principals are language agnostic.
Beginners - Get Started With Unit Testing in .NETBaskar K
Beginners - Get started with unit testing in .NET. Introduction to unit testing and mocking.. List of unit testing frameworks available in .NET - NUnit, xUnit.net, Visual Studio unit test framework. List of mocking frameworks available in .NET - Moq, Rhino Mocks, FakeItEasy, NSubstitue, JustMock, and TypeMock. Introduction to Visual Studio Unit Testing Framework, NUnit and xUnit.net.
The process of changing a software system in such a way that it does not alter the external (observable) behavior of the code yet improves its internal structure, to make it easier to understand and cheaper to modify.
The core idea of lean is to eliminate/reduce non-value-added activities (termed "wastes") and thus increase customer value. The Agile itself is a lean for the software development life cycle, and I am sharing a couple of Agile best practices adopted by my teams to make the Scrum methodology more extra lean.
The presentation contains the best agile practices and their benefits in terms of Lean in an agile methodologies
Improve your development skills with Test Driven DevelopmentJohn Stevenson
A talk at the Graduate Developer community on test driven development. Helping students and graduates understand the point of a test first approach, demonstrate the tools and show how easy it is to start.
This document provides an overview of refactoring and reflection. It discusses refactoring basics like typical refactorings. It also covers refactoring tools in Squeak like the Refactoring Browser. The implementation of the Refactoring Engine is explained, including how it uses an abstract syntax tree (AST) and tree rewriter. Finally, it considers the relationship between refactoring and reflection, noting that refactoring builds its own abstraction layer rather than using the system's reflective capabilities.
The importance of automated unit tests and continuous integration is a well known fact, but in mobile applications unit tests just aren't enough. This presentation shows the importance of UI tests on iOS applications, and demonstrates how to build complex automated UI tests using the modern frameworks, focusing with Apple's UIAutomation framework and Gorilla Logic's FoneMonkey framework.
This document discusses refactoring, which involves restructuring existing code without changing its external behavior or functionality. It provides definitions of refactoring and describes best practices for refactoring code, such as taking small, incremental steps and verifying that automated tests still pass after each change. Specific refactoring techniques are also explained, like extracting duplicate code into methods, removing unnecessary complexity or duplication, and consolidating conditional expressions for clarity. The document cautions against fixing bugs during refactoring and emphasizes making changes in a way that simplifies the code and removes code smells.
This document discusses test-driven development (TDD), a software development technique where test cases are written before implementation code. TDD involves writing a failing test case, then code to pass the test, and refactoring code as needed. Key principles are writing tests first, running tests frequently, and making code changes in small iterative steps. TDD aims to increase code quality and reduce bugs by fully testing code in short cycles.
Unit testing involves writing automated tests to test code. Automated tests are repeatable and help catch bugs before deploying code. The main benefits of unit testing are that it allows developers to test code frequently and in less time, catch bugs before deploying, deploy with confidence, reduce bugs in production, and refactor code with confidence.
There are different types of tests including unit tests, integration tests, and end-to-end tests. Unit tests isolate a unit of code without external dependencies and execute fast but provide less confidence. Integration tests involve external dependencies and provide more confidence but take longer. End-to-end tests drive the application through its UI and provide great confidence but are slow.
Good unit tests
This document outlines an agenda for a presentation on Test Driven Development (TDD) best practices. The agenda includes sections on an overview and introduction to TDD, what TDD is and the process, challenges of TDD, learning and best practices for sustaining TDD, frameworks and variations of TDD, and a question and answer period. Some key best practices discussed are writing tests before code, focusing tests on functionality rather than code structure, and establishing governance and training to ensure proper adoption of TDD.
The document discusses unit testing principles and purposes. It states that unit testing is used to prove that classes work properly in isolation, catch bugs early, enforce high-quality code, and make refactoring safer. Unit testing encourages modular and loosely coupled code. However, it does not replace integration or system testing and not all code can be unit tested. The document also provides examples of when code should be refactored before writing unit tests.
Agile Mumbai 2020 Conference | How to get the best ROI on Your Test Automati...AgileNetwork
- Writing automated tests takes a significant amount of time and effort, often resulting in test code that is twice or three times the size of the actual code being tested. This occurs because tests are written in isolation and dependencies must be mocked.
- A better approach is to write tests that focus on behaviors and public interfaces rather than implementation details. Tests should not break when implementation details change, only when public behaviors change. This allows for easier refactoring of code without breaking tests.
- Rather than focusing solely on unit tests, more effort should be put into system level testing which typically finds twice as many bugs. Tests can also be improved by designing them more formally and moving assertions directly into the code being tested.
TDD is a software development technique where unit tests are written before production code to define desired functionality. The TDD cycle involves writing a test that fails, then code to pass the test, and refactoring code while ensuring tests still pass. This forces critical analysis and design while providing a safety net of regression tests. Benefits include feedback that code works, tests as documentation, and improved design through loose coupling and refactoring with confidence from tests.
Test-driven development (TDD) is a software development process where unit tests are written before code to define desired functionality through a series of short cycles: write a test, see it fail, write minimum code for it to pass, refactor code. Key benefits include more modular/extensible code, catching defects early, and increased confidence through thorough test coverage. Shortcomings include lack of full functional testing and risk of false sense of security if tests have same blind spots as code.
Test-driven development (TDD) is a software development process where unit tests are written before code to define desired functionality. The TDD cycle involves writing a failing test, then code to pass the test, and refactoring code. TDD encourages simple code design and finding defects early. Benefits include more modular, flexible code and increased productivity, while shortcomings include reliance on unit tests and potential for false sense of security. Designing for testability and managing tests is important for large systems.
Test-driven development (TDD) is a software development process where unit tests are written before code to define desired functionality. The TDD cycle involves writing a failing test, then code to pass the test, and refactoring code. TDD encourages simple code design and inspires confidence through comprehensive test coverage. Benefits include more modular, flexible code and catching defects early. Shortcomings include reliance on unit tests and potential for false sense of security. Designing for testability and managing tests is important for large systems.
Test-driven development (TDD) is a software development process where unit tests are written before code to define desired functionality. The TDD cycle involves writing a failing test, then code to pass the test, and refactoring code. TDD encourages simple code design and inspires confidence through automated testing. It helps ensure code meets requirements and is testable from the start.
Test-driven development (TDD) is a software development process where unit tests are written before code to define desired functionality. The TDD cycle involves writing a failing test, then code to pass the test, and refactoring code. TDD encourages simple code design and inspires confidence through automated testing. It helps ensure code meets requirements and is testable from the start.
Test-driven development (TDD) is a software development process where unit tests are written before code to define desired functionality. The TDD cycle involves writing a failing test, then code to pass the test, and refactoring code. TDD encourages simple code design and finding defects early. Benefits include more modular, flexible code and high test coverage catching defects early. Shortcomings include difficulty testing interfaces and potential for false sense of security if not supplemented with other testing. Designing for testability with high cohesion, loose coupling, and published interfaces supports effective TDD.
The document outlines an upcoming programming workshop that will cover various JetBrains IDEs like PyCharm, IntelliJ IDEA, and PhpStorm. It then discusses Test Driven Development (TDD), including what TDD is, the development cycle used in TDD, and benefits like encouraging simple designs and confidence. Different types of software tests are also listed like unit tests, integration tests, acceptance tests, and others. Specific testing techniques like unit testing, integration testing using bottom-up and top-down approaches, and acceptance testing are then explained at a high level. Finally, some important notes on testing like trusting tests and prioritizing maintainability are provided.
This document discusses best practices for unit testing. It addresses common issues like tests that run slowly, are hard to understand, or test the same thing repeatedly. It provides solutions such as grouping test files by criteria and naming conventions to make tests self-documenting. It advises against over-complex mocks and duplicated logic in tests. Tests should be written clearly so others can easily understand what is being tested when debugging or refactoring code. The key messages are to keep tests focused on specific units, refactor tests that become confusing, and make tests self-explanatory through naming and comments.
1. Test Driven Development (TDD) is an agile software development process that involves writing unit tests before developing code. It follows a cycle of writing a failing test, implementing code to pass the test, and refactoring code.
2. TDD can result in lower defect rates and improved code quality through refactoring, though empirical evidence is limited. Common mistakes include forgetting to run tests frequently or writing tests that are too broad.
3. Unit tests should be easy to write and read, reliable, fast, and test individual units of code rather than integrated systems to avoid external dependencies slowing down tests.
White box testing involves testing internal program structure and code. It includes static testing like code reviews and structural testing like unit testing. Static testing checks code against requirements without executing. Structural testing executes code to test paths and conditions. Code coverage metrics like statement coverage measure what code is executed by tests. Code complexity metrics like cyclomatic complexity quantify complexity to determine necessary test cases. White box testing finds defects from incorrect code but may miss realistic errors and developers can overlook own code issues.
This document discusses Test Driven Development (TDD) practices. It outlines two approaches to TDD - the isolation approach which focuses on testing small units independently through dependency substitution, and the vertical slice approach which tests features through their public APIs without isolation. While isolation encourages well-designed code and easy to write tests, it can lead to implementation focus and brittle tests. Vertical slicing allows for changing implementations more easily but makes design discovery and pinpointing failures harder. The document recommends starting with isolation and replacing tests with vertical slices as appropriate. It also provides tips on testing best practices like using builders for test data and refactoring test code.
Unit testing is a method where developers write code to test individual units or components of an application to determine if they are working as intended. The document discusses various aspects of unit testing including:
- What unit testing is and why it is important for finding defects early in development.
- Common unit testing techniques like statement coverage, branch coverage, and path coverage which aim to test all possible paths through the code.
- How unit testing fits into the software development lifecycle and is typically done by developers before handing code over for formal testing.
- Popular unit testing frameworks for different programming languages like JUnit for Java and NUnit for .NET.
The document provides examples to illustrate white box testing techniques
Unit testing involves testing individual units or components of an application to verify that each unit performs as expected. A unit test automates the invocation of a unit of work and checks the expected outcome without relying on other units. Good unit tests are automated, repeatable, easy to implement, run quickly and consistently, and isolate the unit from its dependencies. Integration testing differs in that it involves testing units using real dependencies rather than isolated fakes or stubs. Test-driven development involves writing tests before code so that tests fail initially and then pass after the code is implemented. Unit testing frameworks like NUnit provide attributes to mark tests, expected exceptions, setup and teardown methods, and assertions to validate outcomes.
1. Definitions of TDD
Test oriented development
• Having unit tests or integration tests in the code and write
them out either before or after writing the code. The code
has lots of tests and the value of tests is recognized. Design
probably exists before code writing.
2. Definitions of TDD
Test driven development or/and design
• Test Driven Development: The idea of writing your code in a
test-first manner. You may already have an existing design in
place. Tests are used to enhance the design.
• Test Driven Design: The idea of using a test-first approach as
a fully fledged design technique, where tests are a bonus but
the idea is to drive full design from little to no design
whatsoever. Tests are used to create the design.
3. Two levels of TDD
Acceptance TDD (ATDD)
• With ATDD you write a single acceptance test, and then just
enough production functionality/code to fulfill that test.
• The goal of ATDD is to specify detailed, executable
requirements for your solution on a just in time (JIT) basis.
ATDD is also called Behavior Driven Development (BDD).
4. Two levels of TDD
Developer TDD (TDD)
• With developer TDD you write a single developer test,
sometimes inaccurately referred to as a unit test, and then just
enough production code to fulfill that test.
• The goal of developer TDD is to specify a detailed,
executable design for your solution on a JIT basis.
Developer TDD is often simply called TDD.
5. Two levels of TDD
"Ideally, you'll write a single acceptance test, then to implement
the production code required to fulfill that test you'll take a
developer TDD approach."
7. Red-Green-Refactor
Fail: Write a failing test to prove code or functionality is missing
• A programmer taking a TDD approach refuses to write a new
function until there is first a test that fails because that
function isn’t present (pair programming can help).
Pass: Make the test pass by writing production code that meets
the expectations
• By focusing on writing only the code necessary to pass tests,
designs can be cleaner and clearer than is often achieved by
other methods.
Refactor: Now the code can be cleaned up as necessary
• By re-running the tests, the developer can be confident that
code refactoring is not damaging any existing functionality.
DESIGN
8. Values of TDD
o Is about design specification not just validation
o Helps think through requirements before coding
o Helps focus on clean design and code
o Forces more testable and decoupled program structure
o Results in high code coverage
o Tests can serve as software documentation
o Tests can serve as refactoring safety net
o Automatic regression testing that can provide more specific clues of
defects (faster debugging and fixing)
o Conflicting tests can sometimes point out problems in customer
requirements
9. Unit Tests
A unit test should have the following properties:
• It should be automated and repeatable.
• It should be easy to implement.
• Once it’s written, it should remain for future use.
• Anyone should be able to run it.
• It should run at the push of a button.
• It should run quickly.
A unit test usually comprises 3 main actions:
• Arrange objects, creating and setting them up as necessary.
• Act on an object.
• Assert that something is as expected.
10. String Calculator
1. Create a simple string calculator with a method int Sum(string
numbers)
2. The method can take string of comma delimited 1, 2 or more
numbers, and will return the sum of the numbers
3. For any invalid string input it will return 0
17. So far…
• Had the chance to think about requirements and behaviors
• Didn’t need to worry about errors I’d see if I needed to run
this program to check the results
• Could focus on the design of overall structure and first
method.
• Designed and implemented the first method without
depending on the concrete implementation of the other 2
methods it calls (decoupling)
22. Values of TDD, again
• Is about design specification not just validation
• Helps think through requirements before coding
• Helps focus on clean design and code
• Forces more testable and decoupled program structure
• Results in high code coverage
• Tests can serve as software documentation
• Tests can serve as refactoring safety net
• Automatic regression testing that can provide more specific clues of
defects (faster debugging and fixing)
• Conflicting tests can sometimes point out problems in customer
requirements
23. Pillars of good unit tests
Trustworthiness
• Trustworthy tests don’t have bugs and test the right things.
Developers can accept the test results with confidence.
Maintainability
• Ruin project schedule. Risk loosing the tests when the project
is put on a more aggressive schedule.
Readability
• Foundation of the other 2 pillars.
24. Trustworthiness: Test only one thing
Multiple asserts
• Harder to gave the test a more specific name
• After a failure, subsequent asserts aren’t executed; other
possible symptoms that could discover the problem are
missing
Multiple mocks (verifying whether the object under test
interacted as expected)
• There should be no more than one mock
• All other fake objects will act as stubs
25. Trustworthiness: Test only one thing
Solutions
• Create a separate test for each assert
• Use parameterized tests (EXAMPLE)
31. Trustworthiness: Avoid test logic
switch, if-else, foreach, for, while, try-catch...
• The chances of having bugs in the tests increase
• A test that contains logic is usually testing more than one
thing at a time, which isn’t recommended, because the test is
less readable and more fragile.
32. Trustworthiness…
Make tests easy to run
• Better organized (unit test green zone, categories, test lists),
consistent results...
Assure code coverage
• In TDD because no more code is written than necessary to
pass a failing test case, automated tests tend to cover every
code path
33. Maintainability: Avoid testing private
or protected methods
• Private method tells developers that they can change the
implementation without worrying much about unknown
code that uses it.
• Testing private methods may lead to breaking tests, even
though the overall functionality is correct.
• Wanting to test a method means that it has a known behavior
or contract against the calling code.
• Making it public, extracting to class, making it static, making
it internal (least favorite)
34. Maintainability: Removing test code
duplication
Solutions
• Arrange with shared factory method, which can take
parameters and return values
• Initialize method
• Initialize methods should only contain code that applies to all the
tests in the current test class, or it will be harder to understand.
• Refactor to avoid long and hard to understand initialize method
• Create shared mocks/stubs in initialize method? Sometimes let
each test to call the shared helper method to create them for
better readability.
35. Maintainability: Enforcing test
isolation
Anti-patterns
• Hidden test call: Tests contain direct calls to other tests, which
causes tests to depend on one another
• Constrained test order: Tests are coded to expect a specific
state created by running other tests
• Shared-state corruption: Tests touch shared resources without
first initializing the resources or cleaning those up after testing
Solutions
• Flow testing - do integration testing instead
• Initialize and cleanup for each test
36. Maintainability: Avoiding testing
multiple aspects of the same object
• If we need to validate a BOX object, we may need one assert
for width, one assert to height, one assert for length, one
assert for material...
• Override Equals() method
37. Readability
Asserting with meaning
• Custom message
Separating asserts from actions
• “NO” Assert.AreEqual(COULD_NOT_READ_FILE,
log.GetLineCount("abc.txt"));
Initialize and cleanup
• Developers may not realize that there are mock objects set
up in initialize method. It’s more readable to initialize mock
objects directly in the test, with all their expectations. Can be
refactored into factory/helper methods.
38. Readability
Naming unit tests, basically 3 parts
• The name of the method being tested
• The scenario under which it’s being tested
• The expected behavior when the scenario is invoked
Naming variables
43. “TDD should be treated as an an approach (design aide), not just
as a task”
“Test Driven Development, done right, should make developers
highly aware of design pitfalls like tight coupling, violations of
SRP (Single Responsibility Principle), etc.”
“TDD = Refactoring + TFD”