clientv3/kv_test: Fix quota test

Updates TestKVPutError.  Change the quota to work with systems
that have a 64 KiB page size. Increase the db sync wait time to
one second.  Also, add some comments for the hard coded value.

Signed-off-by: Geoff Levand <geoff@infradead.org>

clientv3/integration/kv_test.go

@@ -17,6 +17,7 @@ package integration
 import (
 	"bytes"
 	"math/rand"
+	"os"
 	"reflect"
 	"strings"
 	"testing"
@@ -35,8 +36,8 @@ func TestKVPutError(t *testing.T) {
 	defer testutil.AfterTest(t)
 
 	var (
-		maxReqBytes = 1.5 * 1024 * 1024
-		quota       = int64(maxReqBytes * 1.2)
+		maxReqBytes = 1.5 * 1024 * 1024 // hard coded max in v3_server.go
+		quota       = int64(int(maxReqBytes) + 8*os.Getpagesize())
 	)
 	clus := integration.NewClusterV3(t, &integration.ClusterConfig{Size: 1, QuotaBackendBytes: quota})
 	defer clus.Terminate(t)
@@ -49,7 +50,7 @@ func TestKVPutError(t *testing.T) {
 		t.Fatalf("expected %v, got %v", rpctypes.ErrEmptyKey, err)
 	}
 
-	_, err = kv.Put(ctx, "key", strings.Repeat("a", int(maxReqBytes+100))) // 1.5MB
+	_, err = kv.Put(ctx, "key", strings.Repeat("a", int(maxReqBytes+100)))
 	if err != rpctypes.ErrRequestTooLarge {
 		t.Fatalf("expected %v, got %v", rpctypes.ErrRequestTooLarge, err)
 	}
@@ -59,7 +60,7 @@ func TestKVPutError(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	time.Sleep(500 * time.Millisecond) // give enough time for commit
+	time.Sleep(1 * time.Second) // give enough time for commit
 
 	_, err = kv.Put(ctx, "foo2", strings.Repeat("a", int(maxReqBytes-50)))
 	if err != rpctypes.ErrNoSpace { // over quota