当FreeOnTerminate = True时,为TThread后代编写Delphi DUnit测试的最佳方式是什么？ TThread后代返回一个需要测试的引用,但是我无法弄清楚如何等待线程在测试中完成…
unit uThreadTests;
interface
uses
Classes,TestFramework;
type
TMyThread = class(TThread)
strict private
FId: Integer;
protected
procedure Execute; override;
public
constructor Create(AId: Integer);
property Id: Integer read FId;
end;
TestTMyThread = class(TTestCase)
strict private
FMyId: Integer;
procedure OnThreadTerminate(Sender: TObject);
protected
procedure SetUp; override;
procedure TearDown; override;
published
procedure TestMyThread;
end;
implementation
{ TMyThread }
constructor TMyThread.Create(AId: Integer);
begin
FreeOnTerminate := True;
FId := AId;
inherited Create(False);
end;
procedure TMyThread.Execute;
begin
inherited;
FId := FId + 1;
end;
{ TestTMyThread }
procedure TestTMyThread.TestMyThread;
//var
// LThread: TMyThread;
begin
// LThread := TMyThread.Create(1);
// LThread.OnTerminate := OnThreadTerminate;
// LThread.WaitFor;
// CheckEquals(2,FMyId);
// LThread.Free;
///// The above commented out code is only useful of FreeOnTerminate = False;
with TMyThread.Create(1) do
begin
OnTerminate := OnThreadTerminate;
WaitFor; /// Not sure how else to wait for the thread to finish?
end;
CheckEquals(2,FMyId);
end;
procedure TestTMyThread.OnThreadTerminate(Sender: TObject);
begin
FMyId := (Sender as TMyThread).Id;
end; /// When FreeOnTerminate = True - THIS LINE CAUSES ERROR: Thread Error the handle is invalid
procedure TestTMyThread.SetUp;
begin
inherited;
end;
procedure TestTMyThread.TearDown;
begin
inherited;
end;
initialization
RegisterTests([TestTMyThread.Suite]);
end.
任何想法都会受到欢迎.
德尔福2010.
解决方法
将线程子类化以使其更可测. TThread和TObject提供了足够的钩子,您可以添加感应变量来观察它到达您想要的状态的某些点.
我看到你可能希望测试的这个特定类的三个方面：
>它根据发送给构造函数的值计算其Id属性的值.
>它计算新线程中的新Id属性,而不是调用构造函数的线程.
>完成后自动释放.
所有这些东西都可以从一个子类测试,但是很难测试,而不需要更改线程的接口. (所有其他答案到目前为止需要更改线程的界面,例如通过添加更多的构造函数参数或通过更改自身的开始方式,这可以使线程在实际程序中使用更加困难或至少更麻烦)
type
PTestData = ^TTestData;
TTestData = record
Event: TEvent;
OriginalId: Integer;
FinalId: Integer;
end;
TTestableMyThread = class(TMyThread)
private
FData: PTestData;
public
constructor Create(AId: Integer; AData: PTestData);
destructor Destroy; override;
procedure AfterConstruction; override;
end;
constructor TTestableMyThread.Create(AId: Integer; const AData: PTestData);
begin
inherited Create(AId);
FData := AData;
end;
destructor TestableMyThread.Destroy;
begin
inherited;
FData.FinalId := Id;
// Tell the test that the thread has been freed
FData.Event.SetEvent;
end;
procedure TTestableMyThread.AfterConstruction;
begin
FData.OriginalId := Id;
inherited; // Call this last because this is where the thread starts running
end;
使用该子类,可以编写一个检查以前识别的三个质量的测试：
procedure TestTMyThread.TestMyThread;
var
Data: TTestData;
WaitResult: TWaitResult;
begin
Data.OriginalId := -1;
Data.FinalId := -1;
Data.Event := TSimpleEvent.Create;
try
TTestableMyThread.Create(1,@Data);
// We don't free the thread,and the event is only set in the destructor,// so if the event is signaled,it means the thread freed itself: That
// aspect of the test implicitly passes. We don't want to wait forever,// though,so we fail the test if we have to wait too long. Either the
// Execute method is taking too long to do its computations,or the thread
// isn't freeing itself.
// Adjust the timeout based on expected performance of Execute.
WaitResult := Data.Event.WaitFor(5000);
case WaitResult of
wrSignaled: ; // This is the expected result
wrTimeOut: Fail('Timed out waiting for thread');
wrAbandoned: Fail('Event was abandoned');
wrError: RaiseLastOSError(Data.Event.LastError);
else Fail('Unanticipated error waiting for thread');
end;
CheckNotEquals(2,Data.OriginalId,'Didn''t wait till Execute to calculate Id');
CheckEquals(2,Data.FinalId,'Calculated wrong Id value');
finally
Data.Event.Free;
end;
end;