1 files changed, 213 insertions, 0 deletions
diff --git a/src/testing/benchmark_test.go b/src/testing/benchmark_test.go
new file mode 100644
index 0000000..2987170
--- /dev/null
+++ b/src/testing/benchmark_test.go
@@ -0,0 +1,213 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package testing_test
+
+import (
+	"bytes"
+	"runtime"
+	"sort"
+	"strings"
+	"sync/atomic"
+	"testing"
+	"text/template"
+	"time"
+)
+
+var prettyPrintTests = []struct {
+	v        float64
+	expected string
+}{
+	{0, "         0 x"},
+	{1234.1, "      1234 x"},
+	{-1234.1, "     -1234 x"},
+	{999.950001, "      1000 x"},
+	{999.949999, "       999.9 x"},
+	{99.9950001, "       100.0 x"},
+	{99.9949999, "        99.99 x"},
+	{-99.9949999, "       -99.99 x"},
+	{0.000999950001, "         0.001000 x"},
+	{0.000999949999, "         0.0009999 x"}, // smallest case
+	{0.0000999949999, "         0.0001000 x"},
+}
+
+func TestPrettyPrint(t *testing.T) {
+	for _, tt := range prettyPrintTests {
+		buf := new(strings.Builder)
+		testing.PrettyPrint(buf, tt.v, "x")
+		if tt.expected != buf.String() {
+			t.Errorf("prettyPrint(%v): expected %q, actual %q", tt.v, tt.expected, buf.String())
+		}
+	}
+}
+
+func TestResultString(t *testing.T) {
+	// Test fractional ns/op handling
+	r := testing.BenchmarkResult{
+		N: 100,
+		T: 240 * time.Nanosecond,
+	}
+	if r.NsPerOp() != 2 {
+		t.Errorf("NsPerOp: expected 2, actual %v", r.NsPerOp())
+	}
+	if want, got := "     100\t         2.400 ns/op", r.String(); want != got {
+		t.Errorf("String: expected %q, actual %q", want, got)
+	}
+
+	// Test sub-1 ns/op (issue #31005)
+	r.T = 40 * time.Nanosecond
+	if want, got := "     100\t         0.4000 ns/op", r.String(); want != got {
+		t.Errorf("String: expected %q, actual %q", want, got)
+	}
+
+	// Test 0 ns/op
+	r.T = 0
+	if want, got := "     100", r.String(); want != got {
+		t.Errorf("String: expected %q, actual %q", want, got)
+	}
+}
+
+func TestRunParallel(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in short mode")
+	}
+	testing.Benchmark(func(b *testing.B) {
+		procs := uint32(0)
+		iters := uint64(0)
+		b.SetParallelism(3)
+		b.RunParallel(func(pb *testing.PB) {
+			atomic.AddUint32(&procs, 1)
+			for pb.Next() {
+				atomic.AddUint64(&iters, 1)
+			}
+		})
+		if want := uint32(3 * runtime.GOMAXPROCS(0)); procs != want {
+			t.Errorf("got %v procs, want %v", procs, want)
+		}
+		if iters != uint64(b.N) {
+			t.Errorf("got %v iters, want %v", iters, b.N)
+		}
+	})
+}
+
+func TestRunParallelFail(t *testing.T) {
+	testing.Benchmark(func(b *testing.B) {
+		b.RunParallel(func(pb *testing.PB) {
+			// The function must be able to log/abort
+			// w/o crashing/deadlocking the whole benchmark.
+			b.Log("log")
+			b.Error("error")
+		})
+	})
+}
+
+func TestRunParallelFatal(t *testing.T) {
+	testing.Benchmark(func(b *testing.B) {
+		b.RunParallel(func(pb *testing.PB) {
+			for pb.Next() {
+				if b.N > 1 {
+					b.Fatal("error")
+				}
+			}
+		})
+	})
+}
+
+func TestRunParallelSkipNow(t *testing.T) {
+	testing.Benchmark(func(b *testing.B) {
+		b.RunParallel(func(pb *testing.PB) {
+			for pb.Next() {
+				if b.N > 1 {
+					b.SkipNow()
+				}
+			}
+		})
+	})
+}
+
+func ExampleB_RunParallel() {
+	// Parallel benchmark for text/template.Template.Execute on a single object.
+	testing.Benchmark(func(b *testing.B) {
+		templ := template.Must(template.New("test").Parse("Hello, {{.}}!"))
+		// RunParallel will create GOMAXPROCS goroutines
+		// and distribute work among them.
+		b.RunParallel(func(pb *testing.PB) {
+			// Each goroutine has its own bytes.Buffer.
+			var buf bytes.Buffer
+			for pb.Next() {
+				// The loop body is executed b.N times total across all goroutines.
+				buf.Reset()
+				templ.Execute(&buf, "World")
+			}
+		})
+	})
+}
+
+func TestReportMetric(t *testing.T) {
+	res := testing.Benchmark(func(b *testing.B) {
+		b.ReportMetric(12345, "ns/op")
+		b.ReportMetric(0.2, "frobs/op")
+	})
+	// Test built-in overriding.
+	if res.NsPerOp() != 12345 {
+		t.Errorf("NsPerOp: expected %v, actual %v", 12345, res.NsPerOp())
+	}
+	// Test stringing.
+	res.N = 1 // Make the output stable
+	want := "       1\t     12345 ns/op\t         0.2000 frobs/op"
+	if want != res.String() {
+		t.Errorf("expected %q, actual %q", want, res.String())
+	}
+}
+
+func ExampleB_ReportMetric() {
+	// This reports a custom benchmark metric relevant to a
+	// specific algorithm (in this case, sorting).
+	testing.Benchmark(func(b *testing.B) {
+		var compares int64
+		for i := 0; i < b.N; i++ {
+			s := []int{5, 4, 3, 2, 1}
+			sort.Slice(s, func(i, j int) bool {
+				compares++
+				return s[i] < s[j]
+			})
+		}
+		// This metric is per-operation, so divide by b.N and
+		// report it as a "/op" unit.
+		b.ReportMetric(float64(compares)/float64(b.N), "compares/op")
+		// This metric is per-time, so divide by b.Elapsed and
+		// report it as a "/ns" unit.
+		b.ReportMetric(float64(compares)/float64(b.Elapsed().Nanoseconds()), "compares/ns")
+	})
+}
+
+func ExampleB_ReportMetric_parallel() {
+	// This reports a custom benchmark metric relevant to a
+	// specific algorithm (in this case, sorting) in parallel.
+	testing.Benchmark(func(b *testing.B) {
+		var compares atomic.Int64
+		b.RunParallel(func(pb *testing.PB) {
+			for pb.Next() {
+				s := []int{5, 4, 3, 2, 1}
+				sort.Slice(s, func(i, j int) bool {
+					// Because RunParallel runs the function many
+					// times in parallel, we must increment the
+					// counter atomically to avoid racing writes.
+					compares.Add(1)
+					return s[i] < s[j]
+				})
+			}
+		})
+
+		// NOTE: Report each metric once, after all of the parallel
+		// calls have completed.
+
+		// This metric is per-operation, so divide by b.N and
+		// report it as a "/op" unit.
+		b.ReportMetric(float64(compares.Load())/float64(b.N), "compares/op")
+		// This metric is per-time, so divide by b.Elapsed and
+		// report it as a "/ns" unit.
+		b.ReportMetric(float64(compares.Load())/float64(b.Elapsed().Nanoseconds()), "compares/ns")
+	})
+}