buffet: Delay removal of completed command

User will need check status of the command.
Processed which handle commands execution needs to check
state of a command to avoid execution of commands in terminal
states.

TEST=unittest
BUG=brillo:431

Change-Id: I72dc65f824bee200ee81a1970330b6e8f2d08fc2
Reviewed-on: https://chromium-review.googlesource.com/263498
Tested-by: Vitaly Buka <vitalybuka@chromium.org>
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
diff --git a/buffet/commands/dbus_command_dispatcher_unittest.cc b/buffet/commands/dbus_command_dispatcher_unittest.cc
index ec3c658..1e27aac 100644
--- a/buffet/commands/dbus_command_dispatcher_unittest.cc
+++ b/buffet/commands/dbus_command_dispatcher_unittest.cc
@@ -30,7 +30,6 @@
 namespace buffet {
 
 namespace {
-
 const char kCommandCategory[] = "test_category";
 
 }  // anonymous namespace
@@ -38,6 +37,8 @@
 class DBusCommandDispacherTest : public testing::Test {
  public:
   void SetUp() override {
+    command_queue_.SetNowForTest(base::Time::Max());
+
     const dbus::ObjectPath kExportedObjectManagerPath("/test/om_path");
     std::string cmd_path = dbus_constants::kCommandServicePathPrefix;
     cmd_path += "1";