我有一个单元测试,我尝试验证我是否已经处理了曾经附加到主用户界面的文档。单元测试必须是异步的,因为一切都需要在 STA 线程下运行,我必须等待创建用户界面。
我有一个助手可以将动作分派到 STA 线程上。
我在测试主体中创建内存对象,然后将其传递给异步方法,如下所示。
查看用###注释的代码行以查看实际的问题行。dotMemory 报告该对象尚不存在,但我已经做出断言证明该对象确实存在。
(STA Helper 类可以在https://gist.github.com/bradphelan/cb4f484fbf6a7f9829de0dd52036fd63找到)
这是与 async 和 dotMemory 有关的问题吗?
[Collection("Memory leaks")]
public class MemLeakSpec
{
public MemLeakSpec(ITestOutputHelper output)
{
DotMemoryUnitTestOutput.SetOutputMethod(output.WriteLine);
}
[Fact]
[DotMemoryUnit(FailIfRunWithoutSupport = true)]
public void ShouldCollectProjectX()
{
dotMemory.Check (memory => { STAThread.Run(() => ShouldCollectProjectAsyncX(memory)).Wait(); });
}
class Document { }
class Container { public Document Document; };
Document CreateFoo() => new Document();
private async Task ShouldCollectProjectAsyncX(Memory memory)
{
await Task.Delay(TimeSpan.FromMilliseconds(50));
Container container = new Container();
memory.GetObjects(@where => @where.Type.Is<Document>())
.ObjectsCount.Should()
.Be(0);
Document documentA = CreateFoo();
container.Document = documentA;
// Verify with dotMemory that the object exists.
// ### This fails even though I have verified
// ### the document exists
memory.GetObjects(@where => @where.Type.Is<Document>())
.ObjectsCount.Should()
.Be(1);
// Open a new project which should dispose the old one and thus
// remove any reference to GenericWeinCadFolder
container.Document = null;
memory.GetObjects(@where => @where.Type.Is<Document>())
.ObjectsCount.Should()
.Be(0);
GC.KeepAlive(container);
}
}
我已经创建了上述相同测试的同步版本,它没有失败。ShouldCollectAsync和ShouldCollectSync下面有两个测试。异步一个失败,同步一个通过。
[Collection("Memory leaks")]
public class MemLeakSpec
{
public MemLeakSpec(ITestOutputHelper output)
{
DotMemoryUnitTestOutput.SetOutputMethod(output.WriteLine);
}
[Fact]
[DotMemoryUnit(FailIfRunWithoutSupport = true)]
public void ShouldCollectAsync()
{
dotMemory.Check (memory => { STAThread.Run(() => ShouldCollectProjectAsyncX(memory)).Wait(); });
}
/// This test is almost identical to the ShouldCollectAsync
/// but it passes
[Fact]
[DotMemoryUnit(FailIfRunWithoutSupport = true)]
public void ShouldCollectSync ()
{
dotMemory.Check (memory => { STAThread.Run(() => ShouldCollectProjectSync(memory)); });
}
class Document { }
class Container { public Document Document; };
Document CreateFoo() => new Document();
private async Task ShouldCollectProjectSync(Memory memory)
{
Container container = new Container();
memory.GetObjects(@where => @where.Type.Is<Document>())
.ObjectsCount.Should()
.Be(0);
Document documentA = CreateFoo();
container.Document = documentA;
// Verify with dotMemory that the object exists.
// #### Passes here
memory.GetObjects(@where => @where.Type.Is<Document>())
.ObjectsCount.Should()
.Be(1);
GC.KeepAlive(documentA);
GC.KeepAlive(container);
}
private async Task ShouldCollectProjectAsyncX(Memory memory)
{
await Task.Delay(TimeSpan.FromMilliseconds(50));
Container container = new Container();
memory.GetObjects(@where => @where.Type.Is<Document>())
.ObjectsCount.Should()
.Be(0);
Document documentA = CreateFoo();
container.Document = documentA;
// Verify with dotMemory that the object exists.
// #### FAILS here
memory.GetObjects(@where => @where.Type.Is<Document>())
.ObjectsCount.Should()
.Be(1);
GC.KeepAlive(documentA);
GC.KeepAlive(container);
}
}