Code Contract (Java and Delphi Cross Reference Guide)

Delphi does not offer built-in Design by Contract features. It does offer an Assert method which tests if an expression is true. If false, an EAssertionFailed exception is raised. Although you can use Assert in a similar manor as you would use a pre-condition contract, the Delphi help clearly says Assert is a debugging tool only and to not use it in production code.

//Although not intended as a code contract feature,

//Assert is useful for debugging.

method Cyborg.Walk(pPace);

begin
  Assert(pPace > 0);
  Assert(pPace < 100);

  //Overloaded version with message.
  Assert(FEnergyLevel >= 10, 'Energy level too low.');
end;