Ui ui = new NoOpUi();
Ui.Task t = ui.pushTask("foo", "bar");
ui.popTask(t, "");
assertEquals("bar", t.description);
t = ui.pushTask("foo", "bar");
try {
ui.popTask(new Ui.Task("baz", "quux"), "");
fail("Expected failure");
} catch (MoeProblem e) {}
}