Add a test to ensure []byte => BlobKey PLS works.

service/datastore/pls_test.go

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // adapted from github.com/golang/appengine/datastore
 
 package datastore
 
 import (
         "bytes"
@@ skipping 1295 matching lines @@
         {
                 desc: "exotic types",
                 src: &ExoticTypes{
                         BS: "sup",
                 },
                 want: &ExoticTypes{
                         BS: "sup",
                 },
         },
         {
+                desc: "exotic type projection",
+                src: PropertyMap{
+                        "BS": {mp([]byte("I'mABlobKey"))},
+                },
+                want: &ExoticTypes{
+                        BS: "I'mABlobKey",
+                },
+        },
+        {
                 desc:   "underspecified types",
                 src:    &Underspecified{},
                 plsErr: "non-concrete interface",
         },
         {
                 desc: "mismatch (string)",
                 src: PropertyMap{
                         "K": {mp(199)},
                         "S": {mp([]byte("cats"))},
                         "F": {mp("nurbs")},
@@ skipping 618 matching lines @@
                         So(pls.SetMeta("id", "sup|1337"), ShouldBeTrue)
                         So(ide.EmbeddedID, ShouldResemble, EmbeddedID{"sup", 1337})
 
                         So(pls.GetAllMeta(), ShouldResembleV, PropertyMap{
                                 "$id":   {mpNI("sup|1337")},
                                 "$kind": {mpNI("IDEmbedder")},
                         })
                 })
         })
 }