Java 编写下载文件的单元测试
当时我写了一个小的下载服务,让用户下载一个文件(目前只有excel)。代码工作正常,但是我不知道如何为它编写单元测试。这是我的密码:Java 编写下载文件的单元测试,java,unit-testing,junit,mockito,Java,Unit Testing,Junit,Mockito,当时我写了一个小的下载服务,让用户下载一个文件(目前只有excel)。代码工作正常,但是我不知道如何为它编写单元测试。这是我的密码: package com.pzm.service; import com.pzm.model.UserBillingsMock; import com.pzm.model.report.ExcelReport; import com.pzm.model.report.Report; import com.pzm.model.report.ReportFactory
package com.pzm.service;
import com.pzm.model.UserBillingsMock;
import com.pzm.model.report.ExcelReport;
import com.pzm.model.report.Report;
import com.pzm.model.report.ReportFactory;
import org.springframework.stereotype.Repository;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;
/**
* Created by akfaz on 6/26/14.
*/
@Repository
public class DownloadService {
private Report report;
private List<UserBillings> userBillings;
public void setBill(List<UserBillings> userBillings) {
this.userBillings = userBillings;
}
public void download(HttpServletResponse response, String reportType) {
response.setContentType("application/vnd.ms-excel");
response.setHeader("Content-Disposition", "attachment; filename=MyExcel.xls");
report = new ReportFactory().create(reportType, userBillings);
saveFile(response, report);
}
private void saveFile(HttpServletResponse response, Report report) {
try {
ServletOutputStream outputStream = response.getOutputStream();
report.write(outputStream);
outputStream.flush();
} catch (IOException e) {
e.printStackTrace();
}
}
}
例外情况是:
org.apache.poi.openxml4j.exceptions.OpenXML4JRuntimeException: Fail to save: an error occurs while saving the package : null
at org.apache.poi.openxml4j.opc.ZipPackage.saveImpl(ZipPackage.java:500)
at org.apache.poi.openxml4j.opc.OPCPackage.save(OPCPackage.java:1417)
at org.apache.poi.POIXMLDocument.write(POIXMLDocument.java:179)
at com.pzm.model.report.ExcelReport.write(ExcelReport.java:46)
at com.pzm.service.DownloadService.saveFile(DownloadService.java:40)
at com.pzm.service.DownloadService.download(DownloadService.java:34)
at com.pzm.service.DownloadServiceTest.testDownload(DownloadServiceTest.java:32)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:83)
at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:74)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:202)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:65)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
Caused by: java.lang.NullPointerException
at java.util.zip.DeflaterOutputStream.<init>(DeflaterOutputStream.java:84)
at java.util.zip.DeflaterOutputStream.<init>(DeflaterOutputStream.java:142)
at java.util.zip.ZipOutputStream.<init>(ZipOutputStream.java:118)
at java.util.zip.ZipOutputStream.<init>(ZipOutputStream.java:104)
at org.apache.poi.openxml4j.opc.ZipPackage.saveImpl(ZipPackage.java:433)
... 28 more
org.apache.poi.openxml4j.exceptions.OpenXML4JRuntimeException:保存失败:保存包时出错:null
位于org.apache.poi.openxml4j.opc.ZipPackage.saveImpl(ZipPackage.java:500)
位于org.apache.poi.openxml4j.opc.OPCPackage.save(OPCPackage.java:1417)
在org.apache.poi.POIXMLDocument.write上(POIXMLDocument.java:179)
在com.pzm.model.report.ExcelReport.write(ExcelReport.java:46)上
位于com.pzm.service.DownloadService.saveFile(DownloadService.java:40)
下载(DownloadService.java:34)
下载com.pzm.service.DownloadServiceTest.testDownload(DownloadServiceTest.java:32)
在sun.reflect.NativeMethodAccessorImpl.invoke0(本机方法)处
在sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)中
在sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)中
位于org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:83)
位于org.junit.runner.JUnitCore.run(JUnitCore.java:157)
位于com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:74)
位于com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:202)
位于com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:65)
在sun.reflect.NativeMethodAccessorImpl.invoke0(本机方法)处
在sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)中
位于com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
原因:java.lang.NullPointerException
位于java.util.zip.DeflaterOutputStream。(DeflaterOutputStream.java:84)
位于java.util.zip.DeflaterOutputStream。(DeflaterOutputStream.java:142)
位于java.util.zip.ZipoutStream。(ZipOutputStream.java:118)
位于java.util.zip.ZipoutStream。(ZipOutputStream.java:104)
位于org.apache.poi.openxml4j.opc.ZipPackage.saveImpl(ZipPackage.java:433)
... 28多
创建模拟对象时
mockResponse = mock(HttpServletResponse.class);
默认情况下,其所有具有引用类型返回类型(减去一些特殊情况)的方法都返回null
因此,此代码段中的getOutputStream()
的返回值
ServletOutputStream outputStream = response.getOutputStream();
是null
您需要设置期望值并指定返回值
when(mockResponse.getOutputStream().thenReturn(/* the value to return when that method is invoked */);
这被称为。您正在模拟HttpServletResponse。因此,在此模拟响应上调用getOutputStream()将返回null,除非在调用此方法时告诉模拟返回OutputStream。您是否可以尝试
Mockito.spy()
而不是Mockito.mock()
来创建mockResponse
?+1这是正确的做法。顺便说一句,您的第一句话并不完全正确-有些引用类型的Mockito默认值不为null,例如collections@DavidWallace AnyCollection
subtype?我不知道。嗯,是的,你在回答中提到的“少数特殊情况”如下。(1) 默认情况下,返回任何包装类型的方法将返回0或false。(2) 默认情况下,返回集合的任何子类型的方法将返回空集合。(3) 默认情况下,标准toString
的任何实现都将返回模拟的名称。(4) 默认情况下,标准compareTo
的任何实现都将返回1。
when(mockResponse.getOutputStream().thenReturn(/* the value to return when that method is invoked */);