diff --git a/src/debug/macho/file_test.go b/src/debug/macho/file_test.go
index 30705b1bc7..a35c8dd650 100644
--- a/src/debug/macho/file_test.go
+++ b/src/debug/macho/file_test.go
@@ -162,6 +162,10 @@ func TestOpen(t *testing.T) {
                                break
                        }

+                       if len(l.Raw()) < 8 {
+                               t.Errorf("open %s, %d, load command %T don't have enough data", tt.file, i, l)
+                       }
+
                        want := tt.loads[i]
                        if want == nil {
                                continue

go version devel +eca45997df Thu Sep 21 03:00:51 2017 +0000 darwin/amd64
GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/hiro/.go"
GORACE=""
GOROOT="/Users/hiro/go"
GOTOOLDIR="/Users/hiro/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="clang"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/wq/dwn8hs0x7njbzty9f68y61700000gn/T/go-build925434951=/tmp/go-build -gno-record-gcc-switches -fno-common"
CXX="clang++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOROOT/bin/go version: go version devel +eca45997df Thu Sep 21 03:00:51 2017 +0000 darwin/amd64
GOROOT/bin/go tool compile -V: compile version devel +eca45997df Thu Sep 21 03:00:51 2017 +0000
uname -v: Darwin Kernel Version 16.7.0: Thu Jun 15 17:36:27 PDT 2017; root:xnu-3789.70.16~2/RELEASE_X86_64
ProductName:	Mac OS X
ProductVersion:	10.12.6
BuildVersion:	16G29
lldb --version: lldb-900.0.45
  Swift-4.0
gdb --version: GNU gdb (GDB) 8.0