diff --git a/src/TDB2.cpp b/src/TDB2.cpp
index 6b0447dd5..e3e99eb1f 100644
--- a/src/TDB2.cpp
+++ b/src/TDB2.cpp
@@ -134,6 +134,7 @@ void TF2::add_line (const std::string& line)
 {
 //  std::cout << "# TF2::add_line " << _file._data << "\n";
 
+  _lines.push_back (line);
   _added_lines.push_back (line);
   _dirty = true;
 }
@@ -466,17 +467,17 @@ void TDB2::modify (const Task& task)
   else
     pending.modify_task (task);
 
-  // TODO Add undo data lines:
   // time <time>
   // old <task>
   // new <task>
   // ---
-/*
-  undo.add_line ("time " + format (time (NULL)) + "\n");
+  Task original;
+  get (task.get ("uuid"), original);
+
+  undo.add_line ("time " + Date ().toEpochString () + "\n");
   undo.add_line ("old " + original.composeF4 ());
   undo.add_line ("new " + task.composeF4 ());
   undo.add_line ("---\n");
-*/
 
   // Add modified task to backlog.
   backlog.modify_task (task);
diff --git a/test/tdb2.t.cpp b/test/tdb2.t.cpp
index 4b0f3e391..2022b858c 100644
--- a/test/tdb2.t.cpp
+++ b/test/tdb2.t.cpp
@@ -32,44 +32,73 @@
 
 Context context;
 
-////////////////////////////////////////////////////////////////////////////////
-void get (std::vector <Task>& pending, std::vector <Task>& completed)
-{
-  TDB tdb;
-  tdb.location (".");
-  tdb.lock ();
-  tdb.loadPending   (pending);
-  tdb.loadCompleted (completed);
-  tdb.unlock ();
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 int main (int argc, char** argv)
 {
-  UnitTest t (1);
+  UnitTest t (15);
 
   try
   {
-    t.pass ("sample");
-/*
-    // Remove any residual test file.
+    // Remove any residual test files.
+    rmdir ("./extensions");
     unlink ("./pending.data");
     unlink ("./completed.data");
     unlink ("./undo.data");
+    unlink ("./backlog.data");
+    unlink ("./synch.key");
 
     // Set the context to allow GC.
     context.config.set ("gc", "on");
 
-    // Try reading an empty database.
-    Filter filter;
-    std::vector <Task> all;
-    std::vector <Task> pending;
-    std::vector <Task> completed;
-    get (pending, completed);
-    t.ok (pending.size () == 0, "TDB Read empty pending");
-    t.ok (completed.size () == 0, "TDB Read empty completed");
+    TDB2 tdb2;
+    tdb2.set_location (".");
 
-    // Add without commit.
+    // Try reading an empty database.
+    std::vector <Task> pending          = tdb2.pending.get_tasks ();
+    std::vector <Task> completed        = tdb2.completed.get_tasks ();
+    std::vector <std::string> undo      = tdb2.undo.get_lines ();
+    std::vector <std::string> backlog   = tdb2.backlog.get_lines ();
+    std::vector <std::string> synch_key = tdb2.synch_key.get_lines ();
+
+    t.is ((int) pending.size (),   0, "TDB2 Read empty pending");
+    t.is ((int) completed.size (), 0, "TDB2 Read empty completed");
+    t.is ((int) undo.size (),      0, "TDB2 Read empty undo");
+    t.is ((int) backlog.size (),   0, "TDB2 Read empty backlog");
+    t.is ((int) synch_key.size (), 0, "TDB2 Read empty synch_key");
+
+    // Add a task.
+    Task task ("[name:\"value\"]");
+    tdb2.add (task);
+
+    pending   = tdb2.pending.get_tasks ();
+    completed = tdb2.completed.get_tasks ();
+    undo      = tdb2.undo.get_lines ();
+    backlog   = tdb2.backlog.get_lines ();
+    synch_key = tdb2.synch_key.get_lines ();
+
+    t.is ((int) pending.size (),   1, "TDB2 after add, 1 pending task");
+    t.is ((int) completed.size (), 0, "TDB2 after add, 0 completed tasks");
+    t.is ((int) undo.size (),      3, "TDB2 after add, 3 undo lines");
+    t.is ((int) backlog.size (),   1, "TDB2 after add, 1 backlog line");
+    t.is ((int) synch_key.size (), 0, "TDB2 after add, 0 synch_key");
+
+
+    task.set ("description", "This is a test");
+    tdb2.modify (task);
+
+    pending   = tdb2.pending.get_tasks ();
+    completed = tdb2.completed.get_tasks ();
+    undo      = tdb2.undo.get_lines ();
+    backlog   = tdb2.backlog.get_lines ();
+    synch_key = tdb2.synch_key.get_lines ();
+
+    t.is ((int) pending.size (),   1, "TDB2 after add, 1 pending task");
+    t.is ((int) completed.size (), 0, "TDB2 after add, 0 completed tasks");
+    t.is ((int) undo.size (),      7, "TDB2 after add, 7 undo lines");
+    t.is ((int) backlog.size (),   2, "TDB2 after add, 2 backlog line");
+    t.is ((int) synch_key.size (), 0, "TDB2 after add, 0 synch_key");
+
+/*
     TDB tdb;
     tdb.location (".");
     tdb.lock ();
@@ -101,7 +130,7 @@ int main (int argc, char** argv)
     completed.clear ();
 
     tdb.lock ();
-    tdb.load (all, context.filter);
+    tdb.load (all);
     all[0].set ("name", "value2");
     tdb.update (all[0]);                                             // P1 C0 N0 M1
     tdb.commit ();                                                   // P1 C0 N0 M0
@@ -119,7 +148,7 @@ int main (int argc, char** argv)
     all.clear ();
 
     tdb.lock ();
-    tdb.loadPending (all, context.filter);
+    tdb.loadPending (all);
     all[0].setStatus (Task::completed);
     tdb.update (all[0]);                                             // P1 C0 N0 M1
     Task t2 ("[foo:\"bar\" status:\"pending\"]");