main_test.go

package rendezvous_test

import (
	"flag"
	"fmt"
	"os"
	"runtime/metrics"
	"strings"
	"testing"
)

func TestMain(m *testing.M) {
	var showMetrics bool
	flag.BoolVar(&showMetrics, "godebug-metrics", false, "show godebug metrics")
	flag.Parse()

	exitCode := m.Run()

	if showMetrics {
		// Dump godebug metrics to investigate https://github.com/golang/go/issues/64649
		descs := metrics.All()
		var godebugMetrics []metrics.Sample
		for i := range descs {
			// skip metrics.KindBad
			if descs[i].Kind == metrics.KindUint64 && strings.HasPrefix(descs[i].Name, "/godebug/") && strings.HasSuffix(descs[i].Name, ":events") {
				godebugMetrics = append(godebugMetrics, metrics.Sample{Name: descs[i].Name})
			}
		}
		if len(godebugMetrics) > 0 {
			metrics.Read(godebugMetrics)
			for i := range godebugMetrics {
				if godebugMetrics[i].Value.Uint64() > 0 {
					fmt.Printf("%s: %v\n", godebugMetrics[i].Name, godebugMetrics[i].Value.Uint64())
				}
			}
		}
	}

	os.Exit(exitCode)
}