old_contents: import pytest
  
  from devito import Eq, Grid, Operator, TimeFunction, configuration # noqa
  from devito.ir.iet import FindNodes, Expression
  
  pytestmark = pytest.mark.skipif(configuration['backend'] != 'ops',
                                  reason="'ops' wasn't selected as backend on startup")
  
  
  class TestOpsExpression(object):
  
      @pytest.mark.parametrize('equation, expected', [
          ('Eq(u.forward,u+1)', 'Eq(ut1[OPS_ACC0(0,0)], ut0[OPS_ACC1(0,0)] + 1)'),
          ('Eq(u.forward,2*u+4)',
           'Eq(ut1[OPS_ACC0(0,0)], 2*ut0[OPS_ACC1(0,0)] + 4)'),
      ])
      def test_ops_expression_convertion(self, equation, expected):
          """
          Tests OPS generated expressions.
          Some basic tests for the generated expression with ops.
  
          Parameters
          ----------
          equation : str
              An string with a :class:`Eq`to be evalueted.
          expected : str
              Expected expression to be generated from devito.
          """
  
          grid = Grid(shape=(4, 4))  # noqa
          u = TimeFunction(name='u', grid=grid)  # noqa
  
          eq_input = eval(equation)
          op = Operator(eq_input)
  
          for _, func in op._func_table.items():
  
              eq_input_calculated = [i.expr for i in FindNodes(Expression).visit(func)]
  
              for expr in eq_input_calculated:
                  assert str(expr) == expected
  
new_contents: import pytest
  
  from devito import Eq, Grid, Operator, TimeFunction, configuration  # noqa
  from devito.ir.iet import FindNodes, Expression
  
  pytestmark = pytest.mark.skipif(configuration['backend'] != 'ops',
                                  reason="'ops' wasn't selected as backend on startup")
  
  
  class TestOpsExpression(object):
  
      @pytest.mark.parametrize('equation, expected', [
          ('Eq(u.forward,u+1)', 'Eq(ut1[OPS_ACC0(0,0)], ut0[OPS_ACC1(0,0)] + 1)'),
          ('Eq(u.forward,2*u+4)',
           'Eq(ut1[OPS_ACC0(0,0)], 2*ut0[OPS_ACC1(0,0)] + 4)'),
          ('Eq(u.forward, a*u.dxl + 1 + c*u.dyr)',
           'Eq(ut1[OPS_ACC0(0,0)], 2.3*(-ut0[OPS_ACC1(-1,0)]/h_x + '
              'ut0[OPS_ACC1(0,0)]/h_x) + 0.00024*(-ut0[OPS_ACC1(0,0)]/h_y'
              ' + ut0[OPS_ACC1(0,1)]/h_y) + 1)'),
      ])
      def test_ops_expression_convertion(self, equation, expected):
          """
          Tests OPS generated expressions.
          Some basic tests for the generated expression with ops.
  
          Parameters
          ----------
          equation : str
              An string with a :class:`Eq`to be evalueted.
          expected : str
              Expected expression to be generated from devito.
          """
  
          grid = Grid(shape=(4, 4))  # noqa
          u = TimeFunction(name='u', grid=grid)  # noqa
          a = 2.3  # noqa
          c = 0.00024  # noqa
  
          eq_input = eval(equation)
          op = Operator(eq_input)
  
          for _, func in op._func_table.items():
  
              eq_input_calculated = [i.expr for i in FindNodes(Expression).visit(func)]
  
              for expr in eq_input_calculated:
                  assert str(expr) == expected
  
subject: Add new test to ops