strconv: make malloc tests more reliable

Fixes issue 3495.

I adapted fmt.TestCountMallocs to fix the
existing tests. As the resulting tests did not
appear to belong to either itoa or ftoa I moved
them into their own file.

R=bradfitz, fullung
CC=golang-dev
http://codereview.appspot.com/5985072

1 files changed, 0 insertions, 30 deletions

diff --git a/src/pkg/strconv/itoa_test.go b/src/pkg/strconv/itoa_test.go
index 1486ee214..e0213ae9a 100644
--- a/src/pkg/strconv/itoa_test.go
+++ b/src/pkg/strconv/itoa_test.go
@@ -5,7 +5,6 @@
 package strconv_test
 
 import (
-	"runtime"
 	. "strconv"
 	"testing"
 )
@@ -126,35 +125,6 @@ func TestUitoa(t *testing.T) {
 	}
 }
 
-func numAllocations(f func()) int {
-	runtime.GC()
-	memstats := new(runtime.MemStats)
-	runtime.ReadMemStats(memstats)
-	n0 := memstats.Mallocs
-	f()
-	runtime.ReadMemStats(memstats)
-	return int(memstats.Mallocs - n0)
-}
-
-var globalBuf [64]byte
-
-func TestAppendUintDoesntAllocate(t *testing.T) {
-	n := numAllocations(func() {
-		var buf [64]byte
-		AppendInt(buf[:0], 123, 10)
-	})
-	want := 1 // TODO(bradfitz): this might be 0, once escape analysis is better
-	if n != want {
-		t.Errorf("with local buffer, did %d allocations, want %d", n, want)
-	}
-	n = numAllocations(func() {
-		AppendInt(globalBuf[:0], 123, 10)
-	})
-	if n != 0 {
-		t.Errorf("with reused buffer, did %d allocations, want 0", n)
-	}
-}
-
 func BenchmarkFormatInt(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		for _, test := range itob64tests {