old_contents: from pyscipopt import Model, quicksum
  
  def test_quicksum():
      m = Model("quicksum")
      x = m.addVar("x")
      y = m.addVar("y")
      z = m.addVar("z")
      c = 2.3
  
      q = quicksum([x,y,z,c]) == 0.0
      s =      sum([x,y,z,c]) == 0.0
  
      assert(q.expr.terms == s.expr.terms)
  
new_contents: from pyscipopt import Model, quicksum
  
  def test_quicksum():
      m = Model("quicksum")
      x = m.addVar("x")
      y = m.addVar("y")
      z = m.addVar("z")
      c = 2.3
  
      q = quicksum([x,y,z,c]) == 0.0
      s =      sum([x,y,z,c]) == 0.0
  
      assert(q.expr.terms == s.expr.terms)
  
  def test_largequadratic():
      # inspired from performance issue on
      # http://stackoverflow.com/questions/38434300
  
      m = Model("dense_quadratic")
      dim = 200
      x = [m.addVar("x_%d" % i) for i in range(dim)]
      expr = quicksum((i+j+1)*x[i]*x[j]
                      for i in range(dim)
                      for j in range(dim))
      cons = expr <= 1.0
      #                              upper triangle,     diagonal
      assert len(cons.expr.terms) == dim * (dim-1) / 2 + dim
      m.addCons(cons)
      # TODO: what can we test beyond the lack of crashes?
  
subject: add test with quicksum for quadratic