#Needs: fonts/AddExtremaTest2.sfd

import sys, fontforge

font=fontforge.open(sys.argv[1])
font.selection.all()

for g in font.selection.byGlyphs:
  c = g.foreground[0]
  d = c.dup()
  if c!=d:
    raise ValueError("Comparison doesn't work")
  d.addExtrema("only_good_rm",1000)
  if c != d:
    raise ValueError("addExtrema perturbed things badly in " + g.glyphname)

c = font["A"].foreground[0]
d = font["B"].foreground[0]
if c==d:
  raise ValueError("Comparison thinks everything is the same")