Explain Go testing patterns and best practices.

Go Testing Patterns: • Table-driven tests • Subtests with t.Run() • Test helpers with t.Helper() • Benchmarks with testing.B • Examples with testable output • Test coverage analysis Table-driven test: func TestAdd(t *testing.T) { tests := []struct { name string a, b int want int }{ {"positive", 2, 3, 5}, {"negative", -1, -2, -3}, {"zero", 0, 5, 5}, } for _, tt := range tests { t.Run(tt.name, func(t *testing.T) { if got := Add(tt.a, tt.b); got != tt.want { t.Errorf("Add(%d, %d) = %d, want %d", tt.a, tt.b, got, tt.want) } }) } } Benchmark: func BenchmarkFib(b *testing.B) { for i := 0; i < b.N; i++ { Fib(20) } } Mocking: • Interfaces for dependency injection • testify/mock for complex mocking • httptest for HTTP testing