Fix error message from KeyForObj when passing an invalid struct.

filter/txnBuf/txnbuf_test.go

Index: filter/txnBuf/txnbuf_test.go
diff --git a/filter/txnBuf/txnbuf_test.go b/filter/txnBuf/txnbuf_test.go
index 3aabcf88484ea0cd0736919a7e7c3a374c88b330..52743862e6be340479c401768f5fb5f14083d557 100644
--- a/filter/txnBuf/txnbuf_test.go
+++ b/filter/txnBuf/txnbuf_test.go
@@ -495,7 +495,9 @@ func TestQuerySupport(t *testing.T) {
 					}
 
 					for i, pm := range vals {
-						So(pm.GetMetaDefault("key", nil), ShouldResemble, ds.MakeKey("Parent", 1, "Foo", expect[i].id))
+						v, err := datastore.GetMetaDefault(pm, "key", nil)
+						So(err, ShouldBeNil)
+						So(v, ShouldResemble, ds.MakeKey("Parent", 1, "Foo", expect[i].id))
 						So(pm["Value"][0].Value(), ShouldEqual, expect[i].val)
 					}
 
@@ -525,7 +527,9 @@ func TestQuerySupport(t *testing.T) {
 					}
 
 					for i, pm := range vals {
-						So(pm.GetMetaDefault("key", nil), ShouldResemble, ds.MakeKey("Parent", 1, "Foo", expect[i].id))
+						v, err := datastore.GetMetaDefault(pm, "key", nil)
+						So(err, ShouldBeNil)
+						So(v, ShouldResemble, ds.MakeKey("Parent", 1, "Foo", expect[i].id))
 						So(pm["Value"][0].Value(), ShouldEqual, expect[i].val)
 					}
 
@@ -554,7 +558,9 @@ func TestQuerySupport(t *testing.T) {
 					}
 
 					for i, pm := range vals {
-						So(pm.GetMetaDefault("key", nil), ShouldResemble, ds.MakeKey("Parent", 1, "Foo", expect[i].id))
+						v, err := datastore.GetMetaDefault(pm, "key", nil)
+						So(err, ShouldBeNil)
+						So(v, ShouldResemble, ds.MakeKey("Parent", 1, "Foo", expect[i].id))
 						So(pm["Value"][0].Value(), ShouldEqual, expect[i].val)
 					}
 
@@ -609,7 +615,10 @@ func TestQuerySupport(t *testing.T) {
 
 					for i, pm := range vals {
 						So(pm["Value"][0].Value(), ShouldEqual, expect[i].val)
-						So(pm.GetMetaDefault("key", nil), ShouldResemble, ds.MakeKey("Parent", 1, "Foo", expect[i].id))
+
+						v, err := datastore.GetMetaDefault(pm, "key", nil)
+						So(err, ShouldBeNil)
+						So(v, ShouldResemble, ds.MakeKey("Parent", 1, "Foo", expect[i].id))
 					}
 
 					return nil
@@ -716,7 +725,10 @@ func TestQuerySupport(t *testing.T) {
 
 					for i, pm := range vals {
 						So(pm["Value"][0].Value(), ShouldEqual, expect[i].val)
-						So(pm.GetMetaDefault("key", nil), ShouldResemble, ds.MakeKey("Parent", 1, "Foo", expect[i].id))
+
+						v, err := datastore.GetMetaDefault(pm, "key", nil)
+						So(err, ShouldBeNil)
+						So(v, ShouldResemble, ds.MakeKey("Parent", 1, "Foo", expect[i].id))
 					}
 
 					return nil