webwork 下载文件的单元测试问题

写了一个action负责文件下载的方法，大概代码如下这样子：

java 代码

public class TravelAdminUploadAction extends BaseAction{

    private Resource resource;

    private ResourceService resourceService;

    private FileInputStream inputStream;

    private String attachmentName;

    public String downLoadFile()  throws Exception {
        resource = resourceService.getResource(id);
        if(resource.getSumLoadCount() != null ){
            resource.setSumLoadCount(resource.getSumLoadCount() + 1 );
        }else{
            resource.setSumLoadCount(1);
        }
        resourceService.updateResource(resource);
        attachmentName = URLEncoder.encode(resource.getAttachmentName(),"UTF-8");
        File input = new File(resource.getResourceUrl());
        inputStream  = new FileInputStream(input);
        return SUCCESS;
    }
    。。。。。。
}

写的测试代码大概如下这样子：

java 代码

public class TravelAdminUploadActionTest extends TestCase {

    private MockControl control;

    private ResourceService resourceService;

    protected void setUp() throws Exception {
        control = MockControl.createControl(ResourceService.class);
        resourceService = (ResourceService) control.getMock();
    }

    public void testDownLoadFile() throws Exception {
        Resource resource = new Resource();
        resource.setAttachmentName("xxxxxx");
        resource.setResourceUrl("c://WINDOWS/winhelp.exe");
        resourceService.getResource(resource.getId());
        control.setReturnValue(resource);
        resourceService.updateResource(resource);
        control.setDefaultVoidCallable();
        control.replay();
        TravelAdminUploadAction action = new TravelAdminUploadAction();
        action.setId(resource.getId());
        action.setInputStream(new FileInputStream(new File(
                "c://WINDOWS/winhelp.exe")));
        action.setResourceService(resourceService);
        action.setResource(resource);
        assertEquals(Action.SUCCESS, action.downLoadFile());
        control.verify();
    }
}

测试是通过了，但是单元测试是不应该跟环境偶合在一起的，

现在测试环境里面用了c://WINDOWS/winhelp.exe这个文件，我特意找的window上都有的文件，

但是放在linux下面的话，这个测试肯定就通不过了，

不知道各位有没有碰到这样的情况，是怎样解决的，可否指点一二