diff --git a/pkg/blobserver/namespace/ns_test.go b/pkg/blobserver/namespace/ns_test.go
index 0ff78ec4d..f63c15677 100644
--- a/pkg/blobserver/namespace/ns_test.go
+++ b/pkg/blobserver/namespace/ns_test.go
@@ -17,15 +17,18 @@ limitations under the License.
 package namespace
 
 import (
+	"reflect"
+	"sort"
 	"testing"
 
+	"camlistore.org/pkg/blob"
 	"camlistore.org/pkg/blobserver"
 	"camlistore.org/pkg/blobserver/storagetest"
+	"camlistore.org/pkg/context"
 	"camlistore.org/pkg/test"
 )
 
-func newTestNamespace(t *testing.T) (sto blobserver.Storage, cleanup func()) {
-	ld := test.NewLoader()
+func newNamespace(t *testing.T, ld *test.Loader) *nsto {
 	sto, err := newFromConfig(ld, map[string]interface{}{
 		"storage": "/good-storage/",
 		"inventory": map[string]interface{}{
@@ -35,9 +38,73 @@ func newTestNamespace(t *testing.T) (sto blobserver.Storage, cleanup func()) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	return sto, func() {}
+	return sto.(*nsto)
 }
 
-func TestNamespace(t *testing.T) {
-	storagetest.Test(t, newTestNamespace)
+func TestStorageTest(t *testing.T) {
+	storagetest.Test(t, func(t *testing.T) (sto blobserver.Storage, cleanup func()) {
+		ld := test.NewLoader()
+		return newNamespace(t, ld), func() {}
+	})
+}
+
+func TestIsolation(t *testing.T) {
+	ld := test.NewLoader()
+	master, _ := ld.GetStorage("/good-storage/")
+
+	ns1 := newNamespace(t, ld)
+	ns2 := newNamespace(t, ld)
+	stoMap := map[string]blobserver.Storage{
+		"ns1":    ns1,
+		"ns2":    ns2,
+		"master": master,
+	}
+
+	want := func(src string, want ...blob.Ref) {
+		if _, ok := stoMap[src]; !ok {
+			t.Fatalf("undefined storage %q", src)
+		}
+		sort.Sort(blob.ByRef(want))
+		var got []blob.Ref
+		if err := blobserver.EnumerateAll(context.TODO(), stoMap[src], func(sb blob.SizedRef) error {
+			got = append(got, sb.Ref)
+			return nil
+		}); err != nil {
+			t.Fatal(err)
+		}
+		if !reflect.DeepEqual(got, want) {
+			t.Errorf("server %q = %q; want %q", src, got, want)
+		}
+	}
+
+	b1 := &test.Blob{Contents: "Blob 1"}
+	b1r := b1.BlobRef()
+	b2 := &test.Blob{Contents: "Blob 2"}
+	b2r := b2.BlobRef()
+	b3 := &test.Blob{Contents: "Shared Blob"}
+	b3r := b3.BlobRef()
+
+	b1.MustUpload(t, ns1)
+	want("ns1", b1r)
+	want("ns2")
+	want("master", b1r)
+
+	b2.MustUpload(t, ns2)
+	want("ns1", b1r)
+	want("ns2", b2r)
+	want("master", b1r, b2r)
+
+	b3.MustUpload(t, ns2)
+	want("ns1", b1r)
+	want("ns2", b2r, b3r)
+	want("master", b1r, b2r, b3r)
+
+	b3.MustUpload(t, ns1)
+	want("ns1", b1r, b3r)
+	want("ns2", b2r, b3r)
+	want("master", b1r, b2r, b3r)
+
+	if _, _, err := ns2.FetchStreaming(b1r); err == nil {
+		t.Errorf("b1 shouldn't be accessible via ns2")
+	}
 }