post exec

app/src/main/java/chess/io/Command.java

@@ -16,4 +16,6 @@ public abstract class Command {
 	}
 
 	public abstract CommandResult execute(Game game, OutputSystem outputSystem);
+
+	public void postExec(Game game, OutputSystem outputSystem) {}
 }

app/src/main/java/chess/io/CommandExecutor.java

@@ -24,6 +24,7 @@ public class CommandExecutor {
 		assert result != CommandResult.Moved || command instanceof PlayerCommand;
 
 		processResult(command, result);
+		command.postExec(game, outputSystem);
 		return result;
 	}
 

app/src/main/java/chess/io/commands/MoveCommand.java

@@ -50,7 +50,7 @@ public class MoveCommand extends PlayerCommand {
 			return CommandResult.NotAllowed;
 		}
 
-		if (shouldPromote(game, outputSystem)) 
+		if (game.pawnShouldBePromoted()) 
 			return CommandResult.ActionNeeded;
 
 		return CommandResult.Moved;
@@ -63,14 +63,18 @@ public class MoveCommand extends PlayerCommand {
 		board.undoMove(move, deadPiece);
 	}
 
-	private boolean shouldPromote(Game game, OutputSystem outputSystem) {
+	@Override
+	public void postExec(Game game, OutputSystem outputSystem) {
+		tryPromote(game, outputSystem);
+	}
+
+	private void tryPromote(Game game, OutputSystem outputSystem) {
 		Coordinate pawnPos = game.pawnPromotePosition();
 
 		if (pawnPos == null)
-			return false;
+			return;
 
 		outputSystem.promotePawn(pawnPos);
-		return true;
 	}
 
 }