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Documentation Course

Master JavaScript Testing

From Unit Tests to End-to-End Mastery

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A premium, industry-ready curriculum teaching the complete JavaScript testing pyramid. Learn to build bulletproof test suites using Jest, React Testing Library, Supertest, and Playwright. Covers everything from mocking databases to constructing robust CI/CD deployment pipelines.

Written by Jatin Jain Saraf · Architect of SupraScan
Free7 modulesIntermediate to AdvancedWritten / Documentation-style7 of 7 modules live

How to use this course

This course works as both a sequential read and a standalone reference. Read front-to-back to build a complete mental model of Postgres under production load. Or jump to any module when you hit a specific incident — VACUUM bloat, a lock queue outage, a query regression after a data load.

Total reading time

~1 hr

across 7 live modules

Built from

10 TB

live blockchain indexer, cut to 2.7 TB

Prerequisite

Zero SQL to production internals

Beginner through senior engineer

Jatin Jain Saraf

Your instructor

Jatin Jain Saraf

Architect of SupraScan, Supra Blockchain's explorer and indexer: 500–1,000 TPS on a PostgreSQL database that grew to 10 TB, now 2.7 TB. The case studies show the production work behind these courses.

Read the case studiesAbout me

Phase 1 — Foundation

Absolute basics · No prior knowledge assumed

1 modules
F-1
Testing Foundations
Why testing matters, the testing pyramid, the AAA pattern, TDD vs BDD, and coverage metrics.

Phase 2 — Practitioner

Production patterns · Real application architecture

3 modules
P-1
Jest Mastery
Configuration, matchers, async testing, mocking, React Testing Library, snapshot testing, and coverage analysis.
P-2
Backend Testing with Node.js
Testing Express APIs, Supertest fundamentals, database testing strategies, mocking repositories/services, Sinon, and Mocha/Chai for legacy projects.
P-3
BDD with Cucumber
Gherkin syntax, step definitions, feature files, and bridging the communication gap with stakeholder collaboration.

Phase 3 — Architect

Engine internals · High-throughput systems · Distributed architecture

3 modules
A-1
End-to-End Testing
Playwright (Primary), Cypress (Comparison), authentication flows, network interception, flaky test prevention, and CI-friendly test architecture.
A-2
CI/CD & Quality Gates
GitHub Actions, coverage reports, pull request validation, and zero-downtime deployment pipelines.
A-3
Capstone Project
Build and test a production-style authentication application (Next.js + Express API) with Jest, RTL, Supertest, Playwright, and GitHub Actions.
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© 2026 Jatin Jain Saraf (JJS). All rights reserved.