Stage 3 · Build

Go Fundamentals for SREs

Testing & Benchmarking

Table-driven tests, testify, benchmarks, and fuzzing for reliable infrastructure code.

7 min readGo for SREBuild

Test Basics

Go has a built-in test framework. Tests live in _test.go files, use the testing package, and run with go test. No external test runner or framework is required.

Goa-basic-test.go

14 linesLn 1, Col 1Go

Test functions start with Test, take a *testing.T, and use t.Fatal or t.Error to report failures. t.Fatal stops the test immediately; t.Error continues execution.

Table-Driven Tests

Table-driven tests are the idiomatic Go pattern. Define a slice of test cases, each with inputs and expected outputs, and loop through them.

Gotable-driven-test-pattern.go

25 linesLn 1, Col 1Go

Each table entry is a self-contained test scenario. t.Run creates named subtests that run independently. If one fails, the others still run, giving you a complete picture of what works and what doesn't.

Subtests and Parallel Execution

Subtests let you organize related assertions. Adding t.Parallel() runs subtests concurrently, which speeds up test suites significantly.

Goparallel-subtests.go

26 linesLn 1, Col 1Go

t.Parallel() signals that a subtest can run concurrently with other parallel subtests. Each parallel subtest gets its own copy of the loop variable via the table-driven pattern.

Testify Assertions

The testify package provides assertion and suite utilities. Assertions reduce boilerplate and produce clearer failure messages.

Gotestify-assertions.go

19 linesLn 1, Col 1Go

assert logs a failure and continues. require logs a failure and stops immediately. Use require for preconditions that must be met for the test to make sense, and assert for the actual assertions.

Benchmarks

Go's testing package includes benchmarking. Benchmark functions take a *testing.B and use a loop with b.N iterations. The test framework adjusts b.N to get stable measurements.

Gowriting-a-benchmark.go

22 linesLn 1, Col 1Go

b.ResetTimer() excludes setup time from measurements. b.RunParallel runs the benchmark across multiple goroutines. Use -benchmem to include allocation counts: go test -bench=. -benchmem.

Fuzzing

Go 1.18+ has built-in fuzzing. Fuzz tests generate random inputs to find edge cases your test cases missed. This is invaluable for parsers, validators, and deserializers.

Gofuzz-test.go

19 linesLn 1, Col 1Go

f.Add provides seed corpus entries. f.Fuzz runs the test function with randomly generated inputs. The fuzzer will find inputs that cause panics, crashes, or assertion failures and save them as regression tests.

Run fuzz tests carefully

Fuzz tests are slow and consume resources. Run them in CI with a time limit: go test -fuzz=FuzzParseDuration -fuzztime=30s. The fuzzer saves interesting inputs to testdata/fuzz/ for regression testing.

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

Stage 3 · Build

Go Fundamentals for SREs

Testing & Benchmarking

Table-driven tests, testify, benchmarks, and fuzzing for reliable infrastructure code.

7 min readGo for SREBuild

Test Basics

Go has a built-in test framework. Tests live in _test.go files, use the testing package, and run with go test. No external test runner or framework is required.

Goa-basic-test.go

14 linesLn 1, Col 1Go

Test functions start with Test, take a *testing.T, and use t.Fatal or t.Error to report failures. t.Fatal stops the test immediately; t.Error continues execution.

Table-Driven Tests

Table-driven tests are the idiomatic Go pattern. Define a slice of test cases, each with inputs and expected outputs, and loop through them.

Gotable-driven-test-pattern.go

25 linesLn 1, Col 1Go

Subtests and Parallel Execution

Subtests let you organize related assertions. Adding t.Parallel() runs subtests concurrently, which speeds up test suites significantly.

Goparallel-subtests.go

26 linesLn 1, Col 1Go

t.Parallel() signals that a subtest can run concurrently with other parallel subtests. Each parallel subtest gets its own copy of the loop variable via the table-driven pattern.

Testify Assertions

The testify package provides assertion and suite utilities. Assertions reduce boilerplate and produce clearer failure messages.

Gotestify-assertions.go

19 linesLn 1, Col 1Go

assert logs a failure and continues. require logs a failure and stops immediately. Use require for preconditions that must be met for the test to make sense, and assert for the actual assertions.

Benchmarks

Go's testing package includes benchmarking. Benchmark functions take a *testing.B and use a loop with b.N iterations. The test framework adjusts b.N to get stable measurements.

Gowriting-a-benchmark.go

22 linesLn 1, Col 1Go

b.ResetTimer() excludes setup time from measurements. b.RunParallel runs the benchmark across multiple goroutines. Use -benchmem to include allocation counts: go test -bench=. -benchmem.

Fuzzing

Go 1.18+ has built-in fuzzing. Fuzz tests generate random inputs to find edge cases your test cases missed. This is invaluable for parsers, validators, and deserializers.

Gofuzz-test.go

19 linesLn 1, Col 1Go

Run fuzz tests carefully

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