Add "MkKeyContext" KeyContext generation function.

service/datastore/datastore_test.go

 // Copyright 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 // adapted from github.com/golang/appengine/datastore
 
 package datastore
 
 import (
         "bytes"
@@ skipping 378 matching lines @@
                                         `field "NonSerializableField" has invalid type: complex64`)
                         })
                 })
         })
 }
 
 func TestPopulateKey(t *testing.T) {
         t.Parallel()
 
         Convey("Test PopulateKey", t, func() {
-                k := KeyContext{"app", "namespace"}.NewKey("kind", "", 1337, nil)
+                k := MkKeyContext("app", "namespace").NewKey("kind", "", 1337, nil)
 
                 Convey("Can set the key of a common struct.", func() {
                         var cs CommonStruct
 
                         So(PopulateKey(&cs, k), ShouldBeTrue)
                         So(cs.ID, ShouldEqual, 1337)
                 })
 
                 Convey("Will not set the value of a singleton struct.", func() {
                         var ss SingletonStruct
@@ skipping 1414 matching lines @@
                         if err != nil {
                                 panic(fmt.Errorf("failed to find absolute path for `%s`", sameLevelDir))
                         }
 
                         ids, err := FindAndParseIndexYAML(abs)
                         So(err, ShouldBeNil)
                         So(ids[1].Kind, ShouldEqual, "Test Foo")
                 })
         })
 }