Measure Core Web Vitals (FCP, LCP, CLS, INP, TTFB) with Playwright. Master performance regression detection.
Screenshot comparison, responsive breakpoints, dynamic content snapshots, cross-browser visual diffs.
Simulate concurrent users, measure throughput, and identify bottlenecks with realistic load scenarios.
Practice finding XSS, CSRF, clickjacking, JWT issues, CORS misconfigurations, and insecure redirects.
Touch gestures, viewport emulation, orientation changes, soft keyboard handling, and mobile-only patterns.
Catalog of broken → fixed test snippets. Train your eye to spot flaky races, brittle selectors, and shared-state leaks in code review.
Curated sequences of challenges per skill — Form Master, Click Expert, Accessibility Champion, and more. Progress syncs across tabs.
Six formal techniques for choosing which tests to write — equivalence partitioning, BVA, decision tables, state transition, pairwise, exploratory charters.
Six elements that turn a bug report from "need more info" into "merged in 24h" — title, repro, expected vs actual, evidence, severity, reproducibility. Bad vs good examples.
Five patterns for shaping the state your tests live on — fixtures, factories, builders, snapshots, seed+cleanup. Trade-offs and pitfalls for each.
Five families of flaky tests with detection strategies, deterministic repros, and fix patterns — timing, network, state, order, environment.
Five patterns for running tests at scale on CI — parallelization, sharding, retries, reporting, flake detection. GitHub Actions YAML with explicit trade-offs.
Five layers of an a11y audit with coverage breakdown — automated (axe-core), keyboard, screen reader, forced colors, cognitive. Plus WCAG 2.2 highlights.
Five mobile-web patterns with explicit emulation-vs-reality gaps — viewport, touch gestures, orientation, soft keyboard, device farms. Plus device-mix tiers.
Five localization bug categories with detection tests — RTL mirroring, CJK truncation, CLDR pluralization, Intl formatting, Unicode normalization. Plus the pseudo-locale cheat.
The methodology around snapshot testing — baseline governance, flaky diff sources, review workflow, cross-browser drift, threshold tuning. Complements the /visual-regression lab.
Five layers (unit, integration, contract, e2e, exploratory) with speed-coverage-cost trade-offs and ratio tables per architecture. Plus the ice-cream cone anti-pattern.
Five HTTP API design principles with tests that verify each — resource modeling, versioning, evolution rules, error envelopes, hypermedia. Plus contract-first vs code-first comparison.
~65 QA terms A-Z with short definitions and cross-links back to the lab where each concept is explored in depth. Searchable reference to use while reading everything else.
Five patterns for LLMs in QA — prompt engineering, mutation-verify LLM tests, LLM-as-judge with calibrated rubric, hallucination detection, token efficiency. 2026 practical reality.