assertEquals("I work as a sheep seller.", getReply(npc));
assertTrue(en.step(player, "offer"));
assertEquals("I sell sheep.", getReply(npc));
assertTrue(en.step(player, "buy"));
assertEquals("A sheep will cost 30. Do you want to buy it?", getReply(npc));
assertTrue(en.step(player, "no"));
assertEquals("Ok, how else may I help you?", getReply(npc));
assertTrue(en.step(player, "buy dog"));