How was Gawain tested physically ?

Gawain cleaves off the stranger's, Green Knight,  head in one blow. Gawain sets off on an arduous journey to meet the Green Knight to satisfy the deal. Gawain rides for months, alone, with no friends but his horse and no one to talk to but God. On the way, he battles beasts and giants and struggles through a harsh, cold country which would have killed a weaker or more faithless man. Gawain also must let the Green Knight cut his head off; that would be exhausting!