Reimplement !drain command

tests/test_inventory_drain.py

@@ -0,0 +1,59 @@
+import unittest
+
+from munch import Munch
+from minecraft.networking.modern import ClientTickEnd
+from minecraft.networking.packets import PacketBuffer
+
+from mosfet.game import ContainerClickDropPacket, Game
+from mosfet.protocol.types import Slot
+
+
+class FakeConnection:
+    def __init__(self):
+        self.packets = []
+
+    def write_packet(self, packet, force=False):
+        self.packets.append((packet, force))
+
+
+class TestInventoryDrain(unittest.TestCase):
+    def test_drop_packet_encodes_throw_whole_stack(self):
+        packet = ContainerClickDropPacket(
+            container_id=0, state_id=7, slot=45)
+        payload = PacketBuffer()
+        packet.write_fields(payload)
+
+        self.assertEqual(packet.id, 0x12)
+        self.assertEqual(payload.get_writable(), bytes.fromhex(
+            '0007002d01040000'))
+
+    def test_drain_waits_for_authoritative_slot_update(self):
+        connection = FakeConnection()
+        game = Game.__new__(Game)
+        game.g = Munch(
+            inv={36: Slot(True, 62, 3)},
+            inventory_state_ids={0: 5},
+            connection=connection,
+            draining=False,
+        )
+
+        self.assertEqual(game.start_drain(), 1)
+        game._tick_drain()
+        self.assertTrue(game.g.draining)
+        self.assertEqual(game.g.drain_waiting['slot'], 36)
+        self.assertIsInstance(connection.packets[0][0],
+                              ContainerClickDropPacket)
+        self.assertEqual(connection.packets[0][0].state_id, 5)
+        self.assertIsInstance(connection.packets[1][0], ClientTickEnd)
+
+        # InventoryManager updates the state id and slot from server packets.
+        game.g.inventory_state_ids[0] = 6
+        game.g.inv[36] = Slot(False)
+        game._tick_drain()
+        self.assertFalse(game.g.draining)
+        self.assertEqual(game.g.drain_dropped, 1)
+        self.assertIsNone(game.g.drain_error)
+
+
+if __name__ == '__main__':
+    unittest.main()