You are right in your thinking as test match depends on wicket so good field plays a big role in run out and cash out. Overs are not a problem in Test matches because here wickets can be played all day so it is more important for the opposition to bowl and field well to take quick wickets and prevent them from scoring big runs like four & six. And if the batsmen can stay on the field for a long time and don't miss single runs then they will be able to collect a lot of runs which should be at least 300+.
Playing the test match requires a lot of patience for the player to stay patient to score runs successfully. Those who watch the test match also have to enjoy the game with a lot of patience. Test match players have to stay on the field with a lot of patience who enter the field to bat, if they enter the field to bat thinking about runs, they can never survive on the field. To survive on the field, you have to bat with patience.