How to access fields of a TTestCase in a TTestSetup class

Question

I am creating unit tests with DUnit. I have a class that takes quite a long time to initialize.

I derive a class TMyTestSetup from TTestSetup and override its Setup met

Answer 1

You can't initialize TTestCase fields for a whole test suite, and here is an explanation why:

unit Tests3;

interface

uses
  TestFramework, TestExtensions, Windows, Forms, Dialogs, Controls, Classes,
  SysUtils, Variants, Graphics, Messages;

type
  TMyTestCase = class(TTestCase)
  private
    FValue: Integer;
  published
    procedure Test1;
    procedure Test2;
  end;

implementation

{ TMyTestCase }

procedure TMyTestCase.Test1;
begin
  FValue:= 99;
  ShowMessage(Format('%p, %d', [Pointer(Self), FValue]));
end;

procedure TMyTestCase.Test2;
begin
  ShowMessage(Format('%p, %d', [Pointer(Self), FValue]));
end;

initialization
  RegisterTest(TMyTestCase.Suite);
end.

If you run the above unit test you will see that the 'Self' addresses shown in Test1 and Test2 methods are different. That means that TMyTestCase object instances are different for Test1 and Test2 calls.

Consequently, any fields you may declare in TMyTestCase class are volatile between test method's calls.

To perform "global" initialization you should declare your object globally, not as TMyTestCase field.