code: def test_isolate():
      assert isolate(1) == (1, 1)
      assert isolate(S.Half) == (S.Half, S.Half)
  
      assert isolate(sqrt(2)) == (1, 2)
      assert isolate(-sqrt(2)) == (-2, -1)
  
      assert isolate(sqrt(2), eps=Rational(1, 100)) == (
          Rational(24, 17),
          Rational(17, 12),
      )
      assert isolate(-sqrt(2), eps=Rational(1, 100)) == (
          Rational(-17, 12),
          Rational(-24, 17),
      )
  
      raises(NotImplementedError, lambda: isolate(I))
  
file_path: sympy/sympy/polys/numberfields/tests/test_utilities.py
imports: from sympy.abc import x
  from sympy.core.numbers import I, Rational
  from sympy.core.singleton import S
  from sympy.functions.elementary.miscellaneous import sqrt
  from sympy.polys import Poly, cyclotomic_poly
  from sympy.polys.domains import FF, QQ
  from sympy.polys.matrices import DomainMatrix, DM
  from sympy.polys.matrices.exceptions import DMRankError
  from sympy.polys.numberfields.utilities import AlgIntPowers, coeff_search, extract_fundamental_discriminant, isolate, supplement_a_subspace
  from sympy.printing.lambdarepr import IntervalPrinter
  from sympy.testing.pytest import raises
label_desc: Use image node_id 8 for calling a global function with example usage: test_isolate() without return types