我的网址连接测试正常进行。然后在1个月后，我在应用程序中运行了所有测试，并且URL连接测试失败，我不知道为什么，因为我没有更改此类。请，有人可以看一下这个测试吗？
现在测试会抛出java.lang.NullPointerException
测试的最初想法来自：https://programmingproblemsandsolutions.blogspot.com/2019/04/abstractmethoderror-is-thrown-on.html
测试：
import org.junit.jupiter.api.Test;
import org.junit.runner.RunWith;
import org.mockito.Mockito;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import static org.junit.jupiter.api.Assertions.assertTrue;
@RunWith(PowerMockRunner.class)
@PrepareForTest({URL.class})
class JsonOutputFromURLImplTest
{
@Test
void currencyValuesNBP() throws IOException
{
class UrlWrapper
{
private URL url;
public UrlWrapper(String spec) throws MalformedURLException
{
url = new URL(spec);
}
private URLConnection openConnection() throws IOException
{
return url.openConnection();
}
}
UrlWrapper url = PowerMockito.mock(UrlWrapper.class);
HttpURLConnection httpURLConnection = Mockito.mock(HttpURLConnection.class);
PowerMockito.when(url.openConnection()).thenReturn(httpURLConnection);
assertTrue(url.openConnection() instanceof HttpURLConnection);
}
}
经过测试的班级
@Service
@NoArgsConstructor
public class JsonOutputFromURLImpl implements JsonOutputFromURL
{
@Override
public String currencyValuesNBP(String APIUrl) throws ConnectionWithApiEX
{
String jsonOutput = null;
try {
URL url = new URL(APIUrl);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setRequestMethod("GET");
httpURLConnection.setRequestProperty("Content-Type", "application/json");
InputStreamReader inputStreamReader = new InputStreamReader(httpURLConnection.getInputStream());
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
jsonOutput = bufferedReader.readLine();
httpURLConnection.disconnect();
} catch (IOException e) {
e.printStackTrace();
}
if(jsonOutput != null)
return jsonOutput;
throw new ConnectionWithApiEX(APIUrl);
}
}
java.lang.NullPointerException
at com.bartosz.kolej.stock.service.impl.JsonOutputFromURLImplTest$1UrlWrapper.openConnection(JsonOutputFromURLImplTest.java:36)
at com.bartosz.kolej.stock.service.impl.JsonOutputFromURLImplTest$1UrlWrapper.access$000(JsonOutputFromURLImplTest.java:25)
at com.bartosz.kolej.stock.service.impl.JsonOutputFromURLImplTest.currencyValuesNBP(JsonOutputFromURLImplTest.java:42)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:532)
at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:115)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$6(TestMethodTestDescriptor.java:170)
at org.junit.jupiter.engine.execution.ThrowableCollector.execute(ThrowableCollector.java:40)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:166)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:113)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:58)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$4(NodeTestTask.java:108)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:98)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:74)
at java.util.ArrayList.forEach(ArrayList.java:1257)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$4(NodeTestTask.java:112)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:98)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:74)
at java.util.ArrayList.forEach(ArrayList.java:1257)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$4(NodeTestTask.java:112)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:98)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:74)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:32)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:51)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:220)
at org.junit.platform.launcher.core.DefaultLauncher.lambda$execute$6(DefaultLauncher.java:188)
at org.junit.platform.launcher.core.DefaultLauncher.withInterceptedStreams(DefaultLauncher.java:202)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:181)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:128)
at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:69)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
答案 0 :(得分：1)
简短的回答：将您的UrlWrapper.openConnection标记为公开，您就可以参加了。
第二：您没有在服务类中测试任何方法，它的代码无关。
第三：PowerMock可以模拟私有方法，它对您不起作用的原因非常复杂。
考虑以下课程
public static class MyClass {
public String A() {
System.out.println("A called");
return "A";
}
private String B() {
System.out.println("B called");
return "B";
}
}
带有Junit4注释：
@org.junit.Test
public void testMockPrivateMethod() throws Exception {
MyClass myClass = PowerMockito.mock(MyClass.class);
PowerMockito.when(myClass.B()).thenReturn("mockB");
//PowerMockito.when(myClass, "B").thenReturn("mockB");
System.out.println(myClass.B());
}
Output:
mockB
带有Junit5注释：
@org.junit.jupiter.api.Test
public void testMockPrivateMethod() throws Exception {
MyClass myClass = PowerMockito.mock(MyClass.class);
PowerMockito.when(myClass.B()).thenReturn("mockB");
System.out.println(myClass.B());
}
Output:
B called
org.mockito.exceptions.misusing.MissingMethodInvocationException:
when() requires an argument which has to be 'a method call on a mock'.
For example:
when(mock.getArticles()).thenReturn(articles);
Also, this error might show up because:
1. you stub either of: final/private/equals()/hashCode() methods.
Those methods *cannot* be stubbed/verified.
Mocking methods declared on non-public parent classes is not supported.
2. inside when() you don't call method on mock but on some other object.
这是因为您需要字节码检测来模拟私有方法。不幸的是，Junit5引擎没有使用PowerMockRunner（它具有自己的扩展机制）。请注意，您可以在Junit5中使用Junit4批注，但是您需要导入vintageRunner。
如您所见，实际方法正在被调用。不幸的是，当您的方法抛出NPE时，您不会看到该异常。