diff --git a/go/src/v.io/x/playground/builder/builder_v23_test.go b/go/src/v.io/x/playground/builder/builder_v23_test.go
index b4ddf87..17325b6 100644
--- a/go/src/v.io/x/playground/builder/builder_v23_test.go
+++ b/go/src/v.io/x/playground/builder/builder_v23_test.go
@@ -5,6 +5,7 @@
 package main_test
 
 import (
+	"bytes"
 	"os"
 	"path/filepath"
 	"strings"
@@ -77,7 +78,7 @@
 	}
 	builder := sh.Cmd(builderPath, args...)
 	builder.Vars["PATH"] = PATH
-	builder.Stdin = string(bundle)
+	builder.SetStdinReader(bytes.NewReader(bundle))
 	builder.PropagateOutput = true
 	builder.Start()
 	return builder