Fix TestGetAdditionalGroups on i686

Fixes: #941

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>

libcontainer/user/user_test.go

@@ -7,6 +7,8 @@ import (
 	"strconv"
 	"strings"
 	"testing"
+
+	"github.com/opencontainers/runc/libcontainer/utils"
 )
 
 func TestUserParseLine(t *testing.T) {
@@ -382,6 +384,12 @@ this is just some garbage data
 }
 
 func TestGetAdditionalGroups(t *testing.T) {
+	type foo struct {
+		groups   []string
+		expected []int
+		hasError bool
+	}
+
 	const groupContent = `
 root:x:0:root
 adm:x:43:
@@ -389,11 +397,7 @@ grp:x:1234:root,adm
 adm:x:4343:root,adm-duplicate
 this is just some garbage data
 `
-	tests := []struct {
+	tests := []foo{
-		groups   []string
-		expected []int
-		hasError bool
-	}{
 		{
 			// empty group
 			groups:   []string{},
@@ -436,12 +440,15 @@ this is just some garbage data
 			expected: nil,
 			hasError: true,
 		},
-		{
+	}
+
+	if utils.GetIntSize() > 4 {
+		tests = append(tests, foo{
 			// groups with too large id
 			groups:   []string{strconv.Itoa(1 << 31)},
 			expected: nil,
 			hasError: true,
-		},
+		})
 	}
 
 	for _, test := range tests {

libcontainer/utils/utils.go

@@ -9,6 +9,7 @@ import (
 	"path/filepath"
 	"strings"
 	"syscall"
+	"unsafe"
 )
 
 const (
@@ -119,3 +120,7 @@ func Annotations(labels []string) (bundle string, userAnnotations map[string]str
 	}
 	return
 }
+
+func GetIntSize() int {
+	return int(unsafe.Sizeof(1))
+}