Load Testing — Overview

Under Reviewv0.1.0-alpha

The ecom-engine load test suite is built on k6 and covers three user-journey scenarios — product browsing, cart management, and full checkout — across five named load profiles ranging from a 10-second smoke test to a 30-minute soak test.

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Prerequisites

Tool	Minimum version	Install
k6	0.50+	winget install k6 or choco install k6
ecom-backend	running	go run ./cmd/api/... or Docker
PostgreSQL	15+	Run ./migrate up before starting the backend
MongoDB	replica-set	Required when db.type: mongodb (transactions)

Only one database backend is needed. Set db.type in config.yaml to postgres or mongodb.

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Directory Structure

load-tests/
├── main.js                   # Entrypoint — setup / default / handleSummary / teardown
├── config/
│   └── profiles.js           # Named load profiles + global SLO thresholds
├── helpers/
│   ├── api.js                # Typed HTTP wrappers with URL-name tags
│   └── data.js               # Test-data generators (users, products)
├── scenarios/
│   ├── browsing.js           # Product listing & search
│   ├── cart.js               # Add-to-cart & cart management
│   ├── checkout.js           # Full order lifecycle + admin fulfilment
│   ├── breaking-point.js     # Step-load throughput finder
│   ├── max-concurrency.js    # Peak concurrent-user finder
│   ├── throughput.js         # Arrival-rate RPS ceiling finder
│   ├── db-saturation.js      # DB connection-pool exhaustion test
│   ├── memory-leak.js        # 30-minute sustained load for heap drift
│   └── race-conditions.js    # Stock atomicity verification
└── reports/                  # Auto-generated JSON reports (git-ignored)

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Quick Start

Start the backend before running any test:

# Terminal 1 — backend
cd ecom-backend
go run ./cmd/api/...

# Terminal 2 — run a smoke test
k6 run -e PROFILE=smoke load-tests/main.js

Common Commands

# Smoke (1 VU, 10 s) — sanity check
k6 run -e PROFILE=smoke load-tests/main.js

# Run a single scenario in smoke mode
k6 run -e PROFILE=smoke -e SCENARIO=browsing  load-tests/main.js
k6 run -e PROFILE=smoke -e SCENARIO=cart      load-tests/main.js
k6 run -e PROFILE=smoke -e SCENARIO=checkout  load-tests/main.js

# Normal load test against a remote server
k6 run -e PROFILE=load -e BASE_URL=https://api.example.com load-tests/main.js

# Stress test (skip rate limiting locally)
k6 run -e PROFILE=stress -e SKIP_RATE_LIMIT=true load-tests/main.js

# Spike test
k6 run -e PROFILE=spike load-tests/main.js

# Soak test (30 min sustained)
k6 run -e PROFILE=soak load-tests/main.js

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Environment Variables

Variable	Default	Description
PROFILE	smoke	Load profile name — see Profiles
SCENARIO	(all)	Force a single scenario: browsing, cart, checkout
BASE_URL	http://localhost:8080	Target API base URL (no trailing slash)
SKIP_RATE_LIMIT	false	Set true to bypass backend rate limiting for local high-VU tests

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Test Lifecycle

main.js implements the standard k6 lifecycle:

Setup registers a fresh admin user, then either seeds 3 products with profile-appropriate stock quantities or tops up existing variants:

Profile	Stock seeded per variant
smoke	100
load	5 000
stress / spike	50 000
soak	10 000

Teardown is informational only — test data (users, carts, orders) is not cleaned up. Reset the database between full regression runs.