diff --git a/samples/errorfs/error_fs.go b/samples/errorfs/error_fs.go
new file mode 100644
index 0000000..6e1a2e1
--- /dev/null
+++ b/samples/errorfs/error_fs.go
@@ -0,0 +1,41 @@
+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package errorfs
+
+import (
+	"reflect"
+	"syscall"
+
+	"github.com/jacobsa/fuse/fuseutil"
+)
+
+const FooContents = "xxxx"
+
+// A file system whose sole contents are a file named "foo" containing the
+// string defined by FooContents.
+//
+// The file system can be configured to returned canned errors for particular
+// operations using the method SetError.
+type FS interface {
+	fuseutil.FileSystem
+
+	// Cause the file system to return the supplied error for all future
+	// operations matching the supplied type.
+	SetError(t reflect.Type, err syscall.Errno)
+}
+
+func New() (fs FS) {
+	panic("TODO")
+}