Course outline

01 · HTTP & REST APIs

02 · Databases & Persistence

03 · Authentication & Authorization

04 · API Design & gRPC

05 · Caching, Queues & Background Jobs

06 · Production-Ready Services

07 · Advanced Auth & Tenant Security

08 · Performance & Caching at Scale

09 · Testing & Release Confidence

Stage 3 · Build

Production-Ready Services

Service Testing

Combine httptest, Testcontainers, contract tests, race detection, and CI database fixtures.

8 min readBuilding Backend ApplicationsBuild

Testing Pyramid

The testing pyramid has many fast unit tests at the base, fewer integration tests in the middle, and a small number of end-to-end tests at the top. Focus on unit and integration tests for the best return on investment.

Type	Speed	Coverage	Cost
Unit	Fast (ms)	Individual functions	Low
Integration	Medium (s)	Component interactions	Medium
E2E	Slow (min)	Full system	High

httptest

Gotesting-handlers-with-httptest.go

26 linesLn 1, Col 1Go

httptest creates fake HTTP requests and records responses. Fake repositories eliminate external dependencies. Tests run in milliseconds without network or database.

Testcontainers

Gotestcontainers-for-postgresql.go

48 linesLn 1, Col 1Go

Testcontainers spins up real PostgreSQL and Redis instances in Docker. Tests run against real databases. Cleanup happens automatically via t.Cleanup.

Contract Tests

Goopenapi-contract-validation.go

20 linesLn 1, Col 1Go

Contract tests verify that your API responses match the OpenAPI specification. If you change a response shape, the contract test fails. This prevents breaking API changes.

Race Detection

Running tests with race detection


# Run with race detector
go test -race ./...

# Run integration tests separately
go test -race -tags=integration ./...

# In CI
go test -race -count=1 -timeout 300s ./...

The race detector finds concurrent access to shared variables without synchronization. It catches data races that cause intermittent test failures and production bugs.

CI Database Fixtures

Gotest-fixtures.go

17 linesLn 1, Col 1Go

Use fixed UUIDs and known data for test fixtures. This makes tests deterministic. ON CONFLICT DO NOTHING prevents failures when fixtures already exist.

Run race detection in CI

Always run go test -race in CI. The race detector catches data races that are nearly impossible to reproduce locally. It adds ~10x overhead but catches critical bugs.

Mark this lesson complete to store local progress and unlock a cleaner resume path the next time you visit.