如何使用 commons-fileupload 编写单元测试？

Question

我正在使用 commons-fileupload 的框架中工作。

现在我需要编写单元测试类。我的疑问是如果 ServletFileUpload 不是一个接口，如何编写模拟测试？还有其他方法来测试我的课程吗？

昨天我使用mockito为Servlet Parts编写了单元测试，这很简单。但我不知道如何为 commons-fileupload 编写测试。

Answer 1

您可以使用 Commons HTTPClient 构建多部分流：

import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

import org.apache.http.HttpEntity;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.MultipartEntityBuilder;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import javax.servlet.ServletException;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ServletFileUploadMock {

    public static class FileUpload {

        private final String filename;
        private final String mimeType;
        private final byte[] contents;

        public FileUpload(String filename, String mimeType, byte[] contents) {
            this.filename = filename;
            this.mimeType = mimeType;
            this.contents = contents;
        }

    }

    public static HttpServletResponse mockServletFileUpload(HttpServlet servlet, List<FileUpload> files,
            Map<String, String> queryParams) throws IOException, ServletException {

        MultipartEntityBuilder builder = MultipartEntityBuilder.create();
        for (FileUpload f : files) {
            builder = builder.addBinaryBody(f.filename, f.contents, ContentType.create(f.mimeType), f.filename);
        }
        HttpEntity entity = builder.build();

        ByteArrayOutputStream os = new ByteArrayOutputStream();
        entity.writeTo(os);
        ByteArrayInputStream is = new ByteArrayInputStream(os.toByteArray());

        HttpServletRequest mockRequest = mock(HttpServletRequest.class);
        when(mockRequest.getMethod()).thenReturn("POST");
        when(mockRequest.getContentType()).thenReturn(entity.getContentType().getValue());
        when(mockRequest.getContentLength()).thenReturn((int)entity.getContentLength());
        when(mockRequest.getInputStream()).thenReturn(new MockServletInputStream(is));

        // Mock query params
        for (Entry<String, String> p : queryParams.entrySet()) {
            when(mockRequest.getParameter(p.getKey())).thenReturn(p.getValue());
        }

        HttpServletResponse mockResponse = mock(HttpServletResponse.class);

        servlet.service(mockRequest, mockResponse);

        return mockResponse;
    }

    public static class MockServletInputStream extends ServletInputStream {

        private final InputStream delegate;

        public MockServletInputStream(InputStream delegate) {
            this.delegate = delegate;
        }

        @Override
        public int read() throws IOException {
            return delegate.read();
        }

    }
}

Answer 2

您可以回到基础知识并通过包装或扩展和覆盖来手动滚动您的模拟对象。有时，不依赖模拟框架来完成所有事情会更容易。

模拟模拟和测试结果

Answer 3

我会考虑将您的 FileUpload 调用包装在另一层中。虽然这听起来有点矫枉过正，但它可以让您非常快速地切换上传库，并具有更好地对您的调用进行单元测试的附加功能...看起来您将您的应用程序与 commons-fileupload 紧密耦合...