testing: add AllocsPerRun
This CL also replaces similar loops in other stdlib
package tests with calls to AllocsPerRun.
Fixes #4461.
R=minux.ma, rsc
CC=golang-dev
https://golang.org/cl/7002055
diff --git a/src/pkg/reflect/all_test.go b/src/pkg/reflect/all_test.go
index 8dd24de..6f006db 100644
--- a/src/pkg/reflect/all_test.go
+++ b/src/pkg/reflect/all_test.go
@@ -13,7 +13,6 @@
"math/rand"
"os"
. "reflect"
- "runtime"
"sync"
"testing"
"time"
@@ -2012,20 +2011,13 @@
}
func noAlloc(t *testing.T, n int, f func(int)) {
- defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(1))
- // once to prime everything
- f(-1)
- memstats := new(runtime.MemStats)
- runtime.ReadMemStats(memstats)
- oldmallocs := memstats.Mallocs
-
- for j := 0; j < n; j++ {
- f(j)
- }
- runtime.ReadMemStats(memstats)
- mallocs := memstats.Mallocs - oldmallocs
- if mallocs > 0 {
- t.Fatalf("%d mallocs after %d iterations", mallocs, n)
+ i := -1
+ allocs := testing.AllocsPerRun(n, func() {
+ f(i)
+ i++
+ })
+ if allocs > 0 {
+ t.Errorf("%d iterations: got %v mallocs, want 0", n, allocs)
}
}
