Define Assert(cond)
  If cond Then Return; EndIf;
  PrintLn("*** FAILED ***");
  error("Assertion failed");
EndDefine

// This example computed GCD of RingElems in QQ (in DoubleX).
Use QQ[x];
F := x^8 -x^7 -8*x^6 -6*x^5 -9*x^3 -16*x^2 -8*x -1;
RRA := RealRootsApprox(F,10^(-10));
Assert(len(RRA) = 3);
