The "Test of Endurance" achievement in MTG Arena is currently bugged and does not consistently unlock, even when meeting the requirement of reaching 50 or more life. There is no current workaround, and players should report the issue to the developers to help ensure it gets fixed.

I have had more than 50 life multiple times no award

This just happened to me twice in starter deck duels today, and it’s happened in the past as well several times

I had the same thing happen to me. I was playing a starter deck duel and finished the match with over 60 hp. Got the "Heal Up!" achievement but not "Test of Endurance".

been following for a while now so I thought I would share this randomly here..
It was through the help of Dr Evian that I managed to rekindle my broken marriage, as my husband had filed for divorce already and with another woman. I was broken and was scared for the future of our kids , (am a mother of 4 btw.) I wanted our marriage back and I wanted to fix things so bad until a friend of mine introduced me to this great herbalist a who did not only fix my marriage within just a week of been in contact with him,but he also though us the importance of intimacy. am overjoyed by sharing this to you all as my husband is back and loves me more than ever. Anyone going through similar issues should not hesitate to reach out to him via Email ( Eviansolution@gmail.com)

I had this same problem yesterday evening. Was playing starter deck games and did the return all creatures from graveyard against a white deck and gained 40 life and won next turn and didn't get the achievement

Same here.

I'm also dealing with this issue. I tried to create my own bug post but I keep getting an error. Perhaps the log file I was trying to upload was too big?