How does the testing package support table-driven tests and benchmarks?

Question

Accepted Answer

// Table-driven test — idiomatic Go
func TestDivide(t *testing.T) {
    tests := []struct {
        name    string
        a, b    float64
        want    float64
        wantErr bool
    }{
        {"normal division", 10, 2, 5.0, false},
        {"negative result", -10, 2, -5.0, false},
        {"division by zero", 10, 0, 0, true},
    }

for _, tc := range tests {
        t.Run(tc.name, func(t *testing.T) {
            got, err := divide(tc.a, tc.b)
            if (err != nil) != tc.wantErr {
                t.Errorf("divide() error = %v, wantErr %v", err, tc.wantErr)
                return
            }
            if got != tc.want {
                t.Errorf("divide() = %v, want %v", got, tc.want)
            }
        })
    }
}

// Benchmark
func BenchmarkDivide(b *testing.B) {
    b.ReportAllocs() // include allocation stats
    for i := 0; i < b.N; i++ { // b.N calibrated by runtime
        _, _ = divide(100.0, 3.0)
    }
}

// Run: go test -bench=BenchmarkDivide -benchmem -count=5
// Compare with: benchstat old.txt new.txt t.Run() creates isolated subtests — failures are reported individually and can be run in parallel with t.Parallel() Use testify/assert for cleaner assertion messages: assert.Equal(t, expected, actual) b.ResetTimer() to exclude setup time from benchmark measurements go test -race -count=10 catches non-deterministic race conditions Examples (func ExampleXxx) serve as documentation and are verified by go test

How does the testing package support table-driven tests and benchmarks?

Table-driven tests use a slice of test cases iterated with t.Run() for isolated subtests. Benchmarks use the testing.B type with a b.N loop that the runtime calibrates automatically.

How does the testing package support table-driven tests and benchmarks?

Table-driven tests use a slice of test cases iterated with t.Run() for isolated subtests. Benchmarks use the testing.B type with a b.N loop that the runtime calibrates automatically.

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