tests: Tidy up trace file loading
tests: Tidy up trace file loading

MathieuDuponchelle/uhttpmock,pwithnall/uhttpmock,Distrotech/uhttpmock,pwithnall/uhttpmock,MathieuDuponchelle/uhttpmock,Distrotech/uhttpmock,MathieuDuponchelle/uhttpmock