/**
         * Turns stones on emoji in for evaluation and checks, if stones are cleared from playing field and if the sprite of the team changes
         *
         * @returns true if number of stones before and after turn in differs and when sprite of emoji changes after turn in
         */
        public IEnumerator TurnInEmoji()
        {
            // before turn in
            var sprite      = Emoji.GetComponent <SpriteRenderer>().sprite;
            var countStones = GameObject.FindGameObjectsWithTag("Stone").Count();

            ButtonEmoji_1.GetComponent <Toggle>().isOn = true;
            ButtonEmoji_2.GetComponent <Toggle>().isOn = true;

            yield return(new WaitForSeconds(0.5f)); // wait for turn in to be processed

            // after turn in
            var spriteNew      = Emoji.GetComponent <SpriteRenderer>().sprite;
            var countStonesNew = GameObject.FindGameObjectsWithTag("Stone").Count();

            Assert.AreNotEqual(spriteNew, sprite, $"Player {_currentPlayer}: Emoji sprite didn't change after turn in");
            Assert.AreNotEqual(countStonesNew, countStones, $"Player {_currentPlayer}: expected stones to be cleared from Emoji after turn in");
        }