--- title: Introduction to Test-Driven Development (TDD) with... description: A comprehensive introduction to Test-Driven Development (TDD) covering why tests matter (confidence and feedback), why testing is hard, and the... canonical: https://daily.dev/posts/introduction-to-test-driven-development-tdd-with-classic-tdd-example-i5irrpw6z twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Introduction to Test-Driven Development (TDD) with Classic TDD Example | daily.dev og:description: A comprehensive introduction to Test-Driven Development (TDD) covering why tests matter (confidence and feedback), why testing is hard, and the... og:url: https://daily.dev/posts/introduction-to-test-driven-development-tdd-with-classic-tdd-example-i5irrpw6z og:image: https://api.daily.dev/og/posts/I5irrpW6Z.png og:image:alt: Introduction to Test-Driven Development (TDD) with Classic TDD Example og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Introduction to Test-Driven Development (TDD) with Classic TDD Example **[Khalil Stemmler](https://daily.dev/sources/khalilstemmler)** · 24 min read · 0 upvotes · 0 comments ## Summary A comprehensive introduction to Test-Driven Development (TDD) covering why tests matter (confidence and feedback), why testing is hard, and the Red-Green-Refactor process. Explains different test types (unit, integration, E2E, acceptance), Double Loop TDD, and the difference between Classic (Inside-Out/Chicago) and Mockist (Outside-In/London) TDD styles. Includes a step-by-step Classic TDD demonstration building a palindrome checker in TypeScript using Jest, walking through multiple Red-Green-Refactor cycles with code examples. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Google Testing Blog: The Way of TDD](https://daily.dev/posts/google-testing-blog-the-way-of-tdd-ee1symmvv) · Google Testing · 1 upvotes · 0 comments --- Tags: [#testing](https://daily.dev/tags/testing), [#typescript](https://daily.dev/tags/typescript), [#tdd](https://daily.dev/tags/tdd), [#jest](https://daily.dev/tags/jest) [View this post on daily.dev](https://daily.dev/posts/introduction-to-test-driven-development-tdd-with-classic-tdd-example-i5irrpw6z) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Introduction to Test-Driven Development (TDD) with Classic TDD Example","url":"https://daily.dev/posts/introduction-to-test-driven-development-tdd-with-classic-tdd-example-i5irrpw6z","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/introduction-to-test-driven-development-tdd-with-classic-tdd-example-i5irrpw6z"},"datePublished":"2026-06-17T11:25:48.909Z","dateModified":"2026-06-17T11:27:58.168Z","description":"A comprehensive introduction to Test-Driven Development (TDD) covering why tests matter (confidence and feedback), why testing is hard, and the...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/be3b1f19b50e996e9f9dc2f22d639844?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/be3b1f19b50e996e9f9dc2f22d639844?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Khalil Stemmler","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Khalil Stemmler","logo":"https://media.daily.dev/image/upload/s--q08_7jGC--/f_auto,q_auto/v1781695534/logos/khalilstemmler?_a=BAMAMiWQ0","url":"https://daily.dev/sources/khalilstemmler"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/introduction-to-test-driven-development-tdd-with-classic-tdd-example-i5irrpw6z","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"testing,typescript,tdd,jest","timeRequired":"PT24M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Khalil Stemmler","item":"https://daily.dev/sources/khalilstemmler"},{"@type":"ListItem","position":3,"name":"Introduction to Test-Driven Development (TDD) with Classic TDD Example"}]} ```