go-testing
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Resilience and concurrency tests in Go, on two microservices of our own written with the standard library
only. orders calls inventory over HTTP through a fault-injecting proxy, which adds latency, answers 500,
drops connections or swallows requests. Each test checks what the user saw and what really happened in
inventory.
| |
|---|
| System under test | own services orders and inventory, with idempotency keys, retries, timeouts and a circuit breaker |
| Language and tools | Go 1.24 · testing + httptest · race detector · native fuzzing · benchmarks · golangci-lint |
| Types of testing | functional API, resilience and chaos, concurrency, fuzzing, performance (benchmarks) |
| Tests | 25 tests + 18 table cases + a fuzz target; coverage of the four packages 94.5 % |
| Test quality | 14/14 planted bugs caught (scripts/mutants.go) |
| Reports | coverage · visual guide |
What is tested
| Suite | Tool | What it proves |
|---|
inventory table tests | httptest | 3 + 15 cases: boundaries, malformed JSON, unknown fields, the body limit (413), 404 and 409 |
inventory idempotency | httptest | the same Idempotency-Key reserves once and always gets the same answer, a refusal too |
inventory concurrency | -race | 50 goroutines for 10 copies: exactly 10 × 201 and 40 × 409, never oversold |
FuzzParseReservation | go test -fuzz | never panics, accepts only valid input, the round trip is lossless |
breaker | fake clock | opens after 5 failures in a row, fails fast, half-open lets exactly one trial through |
orders chaos scenarios | chaos.Proxy | a slow response is retried without a double reservation; a 500 burst; a reset after the reservation; a black hole bounded by timeouts; an outage opens the breaker and recovery closes it; 30 concurrent orders under faults stay consistent |
| benchmarks | go test -bench | Reserve and the handler, with -benchmem, in the CI summary |
Findings
- The fault injector needed a test of its own. The first black-hole run hung the suite. A Go server notices
that the client hung up only after the request body has been read, so the proxy now drains the body first.
- golangci-lint in CI found unchecked
resp.Body.Close errors that go vet let through.
- A missing mutex is caught only by the race detector. All the numbers still added up.
Running it
No local setup: the Open in GitHub Codespaces badge starts a browser VS Code with this repository, its tools and Docker; the container runs go mod download on creation, then go test -race ./... works in the terminal.
Requirements: Go 1.24.
go test -race ./...
go test ./inventory -run '^$' -fuzz FuzzParseReservation -fuzztime 30s
go test -run '^$' -bench . -benchmem ./inventory
go run scripts/mutants.go # mutation check
go run ./cmd/inventory & go run ./cmd/orders &
curl -d '{"sku":"BOOK-2","quantity":1}' localhost:8080/orders
Project structure
inventory/ stock service with idempotency keys; table, concurrency and fuzz tests
orders/ orders service: timeout, retries, circuit breaker; chaos scenarios
breaker/ circuit breaker with an injectable clock
chaos/ fault-injecting reverse proxy
cmd/ runnable inventory and orders servers
scripts/ mutation check
docs/ test plan, test report, guides
CI
.github/workflows/tests.yml runs on push, pull request, nightly at 04:00 UTC and on demand:
- the
test job runs gofmt, go vet and go test -race with cross-package coverage, then golangci-lint, and puts
the benchmarks in the summary;
- the
fuzz job fuzzes the reservation parser for 60 s;
- the
mutants job runs the mutation check.
The coverage report and the guide are published on GitHub Pages.
Releases: committing .github/releases/<tag>.md runs the Release workflow, which creates the tag and the GitHub release with that file as its notes.
Documentation
| Document | What it is |
|---|
docs/test-plan.md | test plan (ISO/IEC/IEEE 29119-3) |
docs/test-report.md | test summary report: latest results, findings, recommendations |
docs/go.md | guide: the fault table, why the second half of each assertion matters, the mutation table |
docs/go.html | the same guide, interactive: a fault switchboard and a circuit breaker to drive by hand |
Part of a portfolio
One of 13 test automation projects by Nail Karimov:
all projects ·
testing map ·
toolbox.
