Lesson 8 • Advanced
Testing in Go 🐹
Write unit tests, table-driven tests, benchmarks, and HTTP handler tests using Go's built-in testing framework — no external libraries needed.
What You'll Learn in This Lesson
- • Go's built-in
testingpackage and conventions - • Table-driven tests — Go's signature testing pattern
- • Benchmarks and memory profiling
- • Testing HTTP handlers with
httptest - • Test helpers, TestMain, and coverage
go test -v to see real test output. Our editor simulates the patterns.1️⃣ Test Basics
Go's testing framework is built right into the language. Test files end with _test.go, test functions start with Test, and you run them with go test.
Try It: Test Basics
Write and run your first Go test
// Testing in Go — Built-in Framework
console.log("=== Go Testing Conventions ===");
console.log("Go has a built-in testing framework — no external library needed!");
console.log();
console.log("Rules:");
console.log(" • Test files end with _test.go");
console.log(" • Test functions start with Test");
console.log(" • Accept *testing.T parameter");
console.log(" • Same package as code being tested");
console.log();
console.log("=== Example ===");
console.log("// math.go");
console.log("func
...2️⃣ Table-Driven Tests
Table-driven tests are Go's most iconic testing pattern. Define test cases as data in a slice, then loop through them with subtests. This makes adding new cases trivial.
Try It: Table-Driven Tests
The most common Go testing pattern
// Table-Driven Tests — Go's Signature Pattern
console.log("=== Table-Driven Tests ===");
console.log("The most common testing pattern in Go.");
console.log("Define test cases as data, loop through them.");
console.log();
console.log("func TestAdd(t *testing.T) {");
console.log(" tests := []struct {");
console.log(" name string");
console.log(" a, b int");
console.log(" expected int");
console.log(" }{");
console.log(' {"positive", 2, 3, 5},');
console.
...3️⃣ Benchmarks & Helpers
Benchmarks measure performance with nanosecond precision. Test helpers reduce duplication. TestMain provides setup and teardown hooks for the entire test suite.
Try It: Benchmarks
Performance benchmarks, helpers, and TestMain
// Benchmarks & Test Helpers
console.log("=== Benchmarks ===");
console.log("Measure performance with the testing framework.");
console.log();
console.log("func BenchmarkAdd(b *testing.B) {");
console.log(" for i := 0; i < b.N; i++ {");
console.log(" Add(2, 3)");
console.log(" }");
console.log("}");
console.log();
console.log(" $ go test -bench=.");
console.log(" BenchmarkAdd-8 1000000000 0.26 ns/op");
console.log(" → 1 billion iterations, 0.26 nanoseconds each");
console.l
...4️⃣ Testing HTTP Handlers
The httptest package lets you test HTTP handlers without starting a real server. Create a request, record the response, and assert on status codes and body content.
Try It: HTTP Tests
Test REST API handlers with httptest
// Testing HTTP Handlers
console.log("=== httptest Package ===");
console.log("Go provides httptest for testing HTTP handlers without a real server.");
console.log();
console.log("func TestGetUsersHandler(t *testing.T) {");
console.log(" // Create a request");
console.log(' req := httptest.NewRequest("GET", "/api/users", nil)');
console.log(" // Create a response recorder");
console.log(" w := httptest.NewRecorder()");
console.log();
console.log(" // Call the handler");
console.l
...⚠️ Common Mistakes
go test -race ./... in CI. It detects data races that only manifest under concurrent load.📋 Quick Reference — Go Skills Mastered
| Lesson | Key Skills |
|---|---|
| 1. Intro | Setup, syntax, fmt package |
| 2. Variables | Types, slices, maps, control flow |
| 3. Functions | Multi-return, closures, defer |
| 4. Structs | Structs, interfaces, pointers |
| 5. Concurrency | Goroutines, channels, select |
| 6. Errors | Error values, wrapping, Is/As |
| 7. Web | HTTP servers, REST, middleware |
| 8. Testing | Table-driven, benchmarks, httptest |
🎉 Course Complete!
Congratulations! You've completed the entire Go course. You can now build, test, and deploy production Go applications — from concurrent services to REST APIs. Consider exploring Go modules, database integration, or Docker deployments next!
Sign up for free to track which lessons you've completed and get learning reminders.