[英]Delphi Mocks – Is it possible to use ‘VAR’ or ‘OUT’ arrangements in a function that is been mocked with a ‘WillReturn’?
我剛開始使用Delphi- Mocks和我的dunit測試,但它幾乎沒有文檔。
問題是:
我正在嘗試編寫測試'Test_LogonUser_CheckPwd_GOOD_PASSWORD'
但我不知道如何模擬函數Fusers.CheckPwd(TEST_USERID,TEST_PASSWORD,ERROR_CODE);
通常我會使用: Fusers.Setup.WillReturn(True).When.CheckPwd(TEST_USERID,TEST_PASSWORD,ERROR_CODE);
但是'ERROR_CODE'是一個OUT值並且給出了編譯錯誤
問題:
這是我的代碼:
///// TDlUsers
interface
type
{$M+}
IDlUsers = Interface(IInterface)
['{3611B437-888C-4919-B304-238A80DAD476}']
function VerifyPassword(UserId: integer; Pwd: string): Boolean;
function CheckPwd(UserId: integer; Pwd: string; out ErrorCode: Integer) : Boolean;
end;
function Dl_Users : IDlUsers;
{$M-}
implementation
type
TDlUsers = class(TDbIControl,IDlUsers)
public
function VerifyPassword(UserId: integer; Pwd: string): Boolean;
function CheckPwd(UserId: integer; Pwd: string; out ErrorCode: Integer; out ErrorMsg:String) : Boolean;
end;
function Dl_Users : IDlUsers;
begin
result := TDlUsers.create;
end;
//// TUserCtrl
interface
uses DlUsers;
type
TUserCtrl = class
private
FUsers : IDlUsers;
public
function LogonUser_CheckPwd(UserID: Integer; Pwd: String): Boolean;
function LogonUser_VerifyPassword(UserID: Integer; Pwd: String): Boolean;
constructor Create; overload;
constructor Create(FUsers : IDlUsers); overload; { used for Dependency injection }
end;
implementation
constructor TUserCtrl.Create;
begin
Create(Dl_Users);
end;
constructor TUserCtrl.Create(FUsers : IDlUsers);
begin
Self.FUsers := FUsers;
end;
function TUserCtrl.LogonUser_VerifyPassword(UserID: Integer; Pwd: String): Boolean;
begin
result := FUsers.VerifyPassword(UserId,Pwd);
end
function TUserCtrl.LogonUser_CheckPwd(UserID: Integer; Pwd: String): Boolean;
var ErrorCode : Integer;
begin
result := FUsers.CheckPwd(UserID,Pwd,ErrorCode);
// do what needs to be done with ErrorCode
end;
///// Unit tests
procedure TestTDlUsers.SetUp;
begin
inherited;
FUsers := TMock<IDlUsers>.Create;
FUserCtrl := TUserCtrl.Create(FUsers);
end;
procedure TestTDlUsers.Test_LogonUser_VerifyPassword_GOOD_PASSWORD;
var Answer : Boolean;
begin
FUsers.Setup.WillReturnDefault('VerifyPassword',False);
FUsers.Setup.WillReturn(True).When.VerifyPassword(TEST_USERID,TEST_PASSWORD);
Answer := FUserCtrl.LogonUser_VerifyPassword(TEST_USERID,TEST_PASSWORD,ErrorCode,ErrorMsg);
CheckEquals(True,Answer);
end;
procedure TestTDlUsers.Test_LogonUser_CheckPwd_GOOD_PASSWORD;
var Answer : Boolean;
begin
FUsers.Setup.WillReturnDefault('CheckPwd',False);
// MAJOR Problem with line CheckPwd has an Out pramater
FUsers.Setup.WillReturn(True).When.CheckPwd(TEST_USERID,TEST_PASSWORD, ERROR_CODE);
Answer := FUserCtrl.LogonUser_CheckPwd(TEST_USERID,TEST_PASSWORD,ErrorCode,ErrorMsg);
CheckEquals(True,Answer);
end;
AFAIK這是對Delphi TVirtualInterface
依賴的TVirtualInterface
標准類實現的限制。 這是“新RTTI”的弱點/局限之一。
唯一可行的解決方案是使用不使用此TVirtualInterface
類的存根/ TVirtualInterface
庫。
我所知道的唯一擁有自己的“虛擬類”工廠的庫是我們的開源mORMot框架 (適用於Delphi 6到XE4,在Win32和Win64下)。 它支持var
和out
值參數。 為了測試出任何的參數值,你可以使用ExpectsTrace()
方法-感謝偉大的“呼叫追蹤” mORMot的功能 。
新的delphi-mock可以使用reference-to-function-WillExecute來做到這一點:
FUsers.Setup.WillExecute('CheckPwd',
// function CheckPwd(UserId: integer; Pwd: string; out ErrorCode: Integer; out ErrorMsg: String) : Boolean;
function (const args : TArray<TValue>; const ReturnType : TRttiType) : TValue
var
aErrorCode: Integer;
aErrorMsg: String;
aResult: Boolean
begin
// check against 5, as arg[0] is tkInterface and the method parameters start with arg[1]
Assert.AreEqual(5, Length(args), 'wrong number of arguments passed to IDlUsers.CheckPwd(UserId: integer; Pwd: string; out ErrorCode: Integer; out ErrorMsg:String) : Boolean');
Assert.IsTrue(args[1].IsType<integer>, 'wrong argument 1 type passed to IDlUsers.CheckPwd(UserId: integer; Pwd: string; out ErrorCode: Integer; out ErrorMsg:String) : Boolean');
Assert.IsTrue(args[2].IsType<string>, 'wrong argument 2 type passed to IDlUsers.CheckPwd(UserId: integer; Pwd: string; out ErrorCode: Integer; out ErrorMsg:String) : Boolean');
Assert.IsTrue(args[3].IsType<Integer>, 'wrong argument 3 type passed to IDlUsers.CheckPwd(UserId: integer; Pwd: string; out ErrorCode: Integer; out ErrorMsg:String) : Boolean');
Assert.IsTrue(args[4].IsType<string>, 'wrong argument 4 type passed to IDlUsers.CheckPwd(UserId: integer; Pwd: string; out ErrorCode: Integer; out ErrorMsg:String) : Boolean');
// ...
arg[3] := TValue.From<Integer>(aErrorCode);
arg[4] := TValue.From<string>(aErrorMsg);
Result := TValue.From<Boolean>(aResult);
end);
(我使用Delphi XE7和DUnitX)
您正在使用的庫不考慮通過引用傳遞的參數。 它將所有參數視為在調用mock時匹配的輸入值。 此外,當調用模擬函數時,它無法為這些參數賦值。
另一種方法是更改函數的界面以使其可測試。 您可以在失敗時拋出異常。 但是,異常並不適合此功能,因為輸入正確的用戶名和密碼不是特殊事件。 相反,請考慮返回錯誤代碼。 保留一個代碼(通常為零)以表示成功。
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