Best of Testing — November 2025

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   Article

   Justin Searls·21w

   TDD is more important than ever

   Test-driven development skills are becoming critical for working effectively with AI coding agents. Developers experienced in TDD are both the most skeptical of AI code generation and the most successful at using it, because they understand how to build verification into workflows. AI agents, like human developers, need independent ways to verify their work—without verification, they resort to guessing, which compounds errors rapidly. The ability to establish automated testing and verification mechanisms, once a hallmark of agile practices, is now essential for enabling AI agents to produce reliable code through reinforcement learning.

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   Article

   Storybook·23w

   Storybook 10

   Storybook 10 transitions to ESM-only, reducing install size by 29% while adding module automocking for easier testing, typesafe CSF Factories for React, tag filtering exclusion for sidebar management, and Svelte async component support. The release includes support for Next 16 and Vitest 4, plus experimental features like test syntax and React Server Component testing. The breaking change requires Node 20.16+, 22.19+, or 24+.

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   Article

   Yegor's Blog·21w

   Small Repo, High Quality

   Breaking software into smaller repositories instead of using monolithic repos improves code quality through stricter style enforcement, deeper testing, more thorough code reviews, better documentation, faster release cycles, improved AI agent effectiveness, quicker onboarding, stronger code ownership, and easier open-source adoption. While companies like Google and Facebook favor monorepos for reduced integration overhead, smaller repositories enable teams to maintain higher quality standards across multiple dimensions of software development.

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   Article

   Storybook·21w

   Storybook MCP sneak peek

   Storybook MCP is a new integration that provides AI coding agents with machine-readable component metadata from your Storybook setup. It helps agents generate higher quality code by giving them access to your existing component patterns, usage examples, and types. The system includes a self-healing loop that runs component tests and allows agents to fix their own bugs autonomously. Benchmarks show 3× faster code generation with 50% fewer tokens while maintaining quality standards. Early access begins December 2 for teams with mature React design systems.

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   Article

   Trendyol Tech·21w

   Test Automation Structure for Single Code Base Projects

   Trendyol's QA team consolidated their Turkish and international test automation suites into a unified Playwright-based framework following their Single Code Base migration. The new architecture uses an npm package for shared utilities, handles multi-country configurations dynamically, integrates translations from their CTMS, and implements test-level parallelization with worker-based user management. The team writes automation tests during development to avoid technical debt, achieving resource efficiency through parallel execution while maintaining test speed across multiple cultures, languages, and devices.

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   Article

   Bun·21w

   Bun v1.3.3

   Bun v1.3.3 fixes 95 issues and introduces several new features. Key additions include CompressionStream and DecompressionStream APIs with support for gzip, deflate, brotli, and zstd formats. Standalone executables now support flags to disable automatic .env and bunfig.toml loading. The test runner gains retry and repeats options for handling flaky tests. A new --no-env-file flag allows disabling automatic environment file loading. SQLite has been upgraded to version 3.51.0, and the runtime now uses Zig 0.15.2. The release includes numerous bug fixes across the bundler, package installer, Windows support, Node.js compatibility, Web APIs, networking, YAML parsing, and TypeScript definitions.

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   Article

   CircleCI·22w

   API testing with Playwright

   Playwright's APIRequestContext enables developers to combine API and UI testing in a single test suite, making tests faster and more reliable. The tutorial covers setting up APIRequestContext with a baseURL configuration, sending HTTP requests directly in tests, persisting authenticated state across test runs using storage state files, and automating the entire testing process through CircleCI pipelines. This approach eliminates redundant UI interactions for tasks like authentication, allowing tests to use API calls for setup while focusing UI tests on actual user interface validation.

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   Article

   The Register·23w

   Microsoft's lack of quality control is out of control

   Microsoft's quality control has deteriorated significantly since 2014 when the company laid off many testers in favor of agile methodologies. Recent years have seen repeated issues including the Windows 10 October 2018 Update that deleted user files, frequent problematic Windows updates, and multiple Azure outages caused by faulty configuration changes. While some Windows issues may be understandable given the vast ecosystem, the recurring Azure production failures raise serious questions about Microsoft's competence in managing its own infrastructure.

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   Article

   ploeh blog·22w

   100% coverage is not that trivial

   Challenges the common belief that achieving 100% code coverage is trivial by writing assertion-free tests with try/catch blocks. Demonstrates through practical examples that real-world code with database queries and indirect inputs requires substantial integration testing effort to reach high coverage. Argues that while code coverage remains a poor target metric due to human response to incentives, high coverage numbers are genuinely difficult to achieve and indicate meaningful testing work.

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    Article

    Buildkite·23w

    Changelog roundup: October '25

    Buildkite's October 2025 updates introduce Test Engine workflows for automated test management and labeling, GitHub merge queue integration for Pipelines, direct YAML secrets integration with policy-based access control, team-based permissions for block and input steps, NuGet registry support for .NET packages, Google Cloud Storage integration for Private Storage Link, and webhook notifications for package creation events. Additional improvements include HTML artifact rendering, Xcode 26 support for macOS hosted agents, and enhanced filtering capabilities across the platform.

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