Mocking interfaces in DUnit with Delphi-Mocks and Spring4D - delphi

Question

So, I am getting Access Violation error when try to Mock 2-nd composite interface, below examples of code with using Delphi-Mocks and Spring4D frameworks
unit u_DB;
type
TDBObject = class
public
property ID: TGUID;
end;
TDBCRM = class(TDBObject)
public
property SOME_FIELD: TSomeType;
end;
unit i_dmServer;
type
{$M+}
IdmServer = interface
['{A4475441-9651-4956-8310-16FB710EAE5E}']
function GetServiceConnection: TServiceConnection;
function GetCurrentUser(): TUser;
end;
unit d_ServerWrapper;
type
TdmServerWrapper = class(TInterfacedObject, IdmServer)
private
function GetServiceConnection: TServiceConnection;
function GetCurrentUser(): TUser;
protected
FdmServer: TdmServer;
end;
implementation
constructor TdmServerWrapper.Create();
begin
inherited Create();
FdmServer := TdmServer.Create(nil);
end;
end.
unit i_BaseDAL;
type
{$M+}
IBaseDAL<T: TDBObject, constructor> = interface
['{56D48844-BD7F-4FF8-A4AE-30DA1A82AD67}']
procedure RefreshData(); ....
end;
unit u_BaseDAL;
type
TBaseDAL<T: TDBObject, constructor> = class(TInterfacedObject, IBaseDAL<TDBObject>)
protected
FdmServer: IdmServer;
public
procedure RefreshData();
end;
implementation
procedure TBaseDAL<T>.Create;
begin
FdmServer := GlobalContainer.Resolve<IdmServer>;
end;
end.
unit ChildFrame;
interface
type
TChildFrame = class(TFrame)
private
fDM: IBaseDAL<TDBObject>;
function GetDM: IBaseDAL<TDBObject>;
procedure SetDM(const Value: IBaseDAL<TDBObject>);
public
constructor Create(AOwner: TComponent); override;
property DM: IBaseDAL<TDBObject> read GetDM write SetDM;
end;
implementation
constructor TChildFrame.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
DM := nil;
end;
function TChildFrame.GetDM: IBaseDAL<TDBObject>;
begin
if not Assigned(fDM) then
fDM := GlobalContainer.Resolve<IBaseDAL<TDBObject>>;
Result := fDM;
end;
procedure TfrmCustomChildFrame.SetDM(const Value: IBaseDAL<TDBObject>);
begin
if Assigned(fDM) then
fDM := nil;
fDM := Value;
end;
end.
TCRMFrame = class(TChildFrame)
....
end;
procedure TCRMFrame.Create
begin
DM := GlobalContainer.Resolve('i_BaseDAL.IBaseDAL<u_DB.TDBObject>#TBaseDAL<u_DB.TDBCRM>').AsInterface as IBaseDAL<TDBObject>;
// DM := GlobalContainer.Resolve(IBaseDAL<TomDBObject>); {Not compiled et all: "E2250 There is no overloaded version of 'Resolve' that can be called with these arguments"}
end;
REGISTERING TYPES
unit RegisteringTypes.pas
procedure RegTypes;
implementation
procedure RegTypes;
begin
GlobalContainer.RegisterType<TdmServerWrapper>;
GlobalContainer.RegisterType<TBaseDAL<TDBObject>, IBaseDAL<TDBObject>>;
GlobalContainer.RegisterType<TBaseDAL<TDBCRM>, IBaseDAL<TDBCRM>>;
GlobalContainer.Build;
end;
initialization
RegTypes
end.
DUNIT TEST
type
TestTCRM = class(TTestCase)
private
FFrame: TCRMFrame;
FBaseDALMock: TMock<TBaseDAL<TDBObject>>;
procedure Init;
protected
procedure SetUp; override;
published
end;
implementation
procedure TestTCRM.Init;
begin
inherited;
GlobalContainer.RegisterType<IdmServer>.DelegateTo(
function: IdmServer
begin
Result := TMock<IdmServer>.Create;
end
);
GlobalContainer.RegisterType<IBaseDAL<TDBCRM>>.DelegateTo(
function: IBaseDAL<TDBCRM>
begin
Result := TMock<IBaseDAL<TDBCRM>>.Create;
end
);
GlobalContainer.RegisterType<IBaseDAL<TDBObject>>.DelegateTo(
function: IBaseDAL<TDBObject>
begin
Result := TMock<IBaseDAL<TDBObject>>.Create;
end
);
GlobalContainer.Build;
end;
procedure TestTfrCRMAccountClasses.SetUp;
begin
inherited;
Init;
FFrame := TCRMFrame.Create(nil); // and I got ACCESS VIOLATION HERE
end;
Full sources of test project here - https://drive.google.com/file/d/0B6KvjsGVp4ONeXBNenlMc2J0R2M.
Colleagues, please advise me where I am wrong. Thank you in advance!

Answer 1

The AV is raised from Delphi.Mocks.
Here is a minimal test case to reproduce it:
procedure DelphiMocksTest;
var
func: TFunc<IdmServer>;
dm: IdmServer;
i: IInitializable;
begin
func :=
function: IdmServer
begin
Result := TMock<IdmServer>.Create;
Supports(dm, IInitializable, i); // works
end; // TMock record goes out of scope and something happens
dm := func();
Supports(dm, IInitializable, i); // fails
end;

Answer 2

You need to have a reference to the TMock somewhere, because the mocks are records which will get cleaned up when they go out of scope.
This should work :
procedure DelphiMocksTest;
var
func: TFunc<IdmServer>;
dm: IdmServer;
i: IInitializable;
mock : TMock<IdmServer>;
begin
func := function: IdmServer
begin
mock := TMock<IdmServer>.Create;
Supports(dm, IInitializable, i); // works
result := mock;
end;
dm := func();
Supports(dm, IInitializable, i); // fails
end;