下面的单元测试无法模拟被测试Java代码的DeleteResult。获取一个NullPointerException。我正在JUnit上运行测试。与delete语句中的过滤器有关吗？
@InjectMocks
DBConnection mongoConnect;
@Mock
MongoClient mockClient;
@Mock
MongoCollection<Document> mockCollection;
@Mock
MongoDatabase mockDB;
@Mock
LinkedList<String> mockArrList;
@Mock
MongoIterable<String> mongoIter;
@Mock
DeleteResult mockDeleteResult;
@SuppressWarnings("unchecked")
@Test
public void deleteDocTest1() {
Mockito.when(mockClient.getDatabase(Mockito.anyString())).thenReturn(mockDB);
MongoIterable<String> mongoIter = Mockito.mock(MongoIterable.class);
Mockito.when(mockDB.listCollectionNames()).thenReturn(mongoIter);
Mockito.when(mongoIter.into(new LinkedList<String>())).thenReturn(mockArrList);
Mockito.when(mockArrList.contains(Mockito.anyString())).thenReturn(true);
Mockito.when(mockDB.getCollection(Mockito.anyString())).thenReturn(mockCollection);
Mockito.when(mockCollection.deleteOne(Filters.and(Filters.eq("aid", "TS123"),
Filters.eq("year", "2018"),
Filters.eq("position", "testCases"))))
.thenReturn(mockDeleteResult);
Mockito.when(mockDeleteResult.getDeletedCount()).thenReturn(1L);
String msg = mongoConnect.deleteDocument("TS123", "testCases", "2018");
assertEquals("Delete Successful", msg);
}
如果键匹配，正在测试的代码只需删除一条记录，如果没有这样的记录，则返回警告。下面的方法正在测试中，它是DBCollection类的一部分：
public String deleteDocument(String aId, String collection, String year) {
MongoDatabase database = mongoClient.getDatabase(databaseName);
//checking if collection is present in the DB
boolean collectionExists = database.listCollectionNames().into(new LinkedList<String>())
.contains(collection);
if(collectionExists) {
MongoCollection<Document> collectionDocs = database.getCollection(collection);
System.out.println(assoId+" "+collection+" "+year);
DeleteResult deleteResult = collectionDocs.deleteOne(Filters.and(Filters.eq("aid", aId), Filters.eq("year",year), Filters.eq("position",collection)));
if(deleteResult.getDeletedCount() == 0) //the ERROR is at this line
return "Delete: record does not exist";
}else {
return "Delete: record does not exist";
}
mongoClient.close();
return "Successful Delete";
}
错误的堆栈跟踪：
java.lang.NullPointerException
at com.repo.repository.DBConnection.deleteDocument(DBConnection.java:103)
at com.repo.form_upload.test.DBTest.deleteDocTest1(DBTest.java:138)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.mockito.internal.junit.JUnitRule$1.evaluate(JUnitRule.java:16)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.mockito.internal.runners.JUnit45AndHigherRunnerImpl.run(JUnit45AndHigherRunnerImpl.java:37)
at org.mockito.runners.MockitoJUnitRunner.run(MockitoJUnitRunner.java:62)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)
有什么问题的想法吗？
最佳答案
这里的问题是这种期望：
Mockito.when(mockCollection.deleteOne(Filters.and(Filters.eq("aid", "TS123"),
Filters.eq("year", "2018"),
Filters.eq("position", "testCases"))))
.thenReturn(mockDeleteResult);
Bson没有实现equals，因此当Mockito尝试确定是否应从collectionsDocs.deleteOne中的deleteDocument调用返回某些内容时，它无法与filter参数匹配，因此它确定collectionsDocs.deleteOne不返回任何内容。要验证这一点，只需运行以下代码：Bson one = Filters.and(Filters.eq("aid", "TS123"),
Filters.eq("year", "2018"),
Filters.eq("position", "testCases"));
Bson two = Filters.and(Filters.eq("aid", "TS123"),
Filters.eq("year", "2018"),
Filters.eq("position", "testCases"));
// one and two are not equal because Bson does not implement equals so
// we'll just fall back to the standard instance check in Object
assertNotEquals(one, two);
如果您这样表示
deleteOne期望，则您的测试将通过-尽管对过滤器的特异性较低-Mockito.when(mockCollection.deleteOne(any(Bson.class))).thenReturn(mockDeleteResult);
或者，您可以使用自定义匹配器对Bson应用自己的均等支票。例如，您可以将
mockCollection.deleteOne期望更改为以下内容：Mockito.when(mockCollection.deleteOne(argThat(new BsonMatcher(Filters.and(Filters.eq("aid", "TS123"),
Filters.eq("year", "2018"),
Filters.eq("position", "testCases"))))))
.thenReturn(mockDeleteResult);
并声明
BsonMatcher如下：public class BsonMatcher implements ArgumentMatcher<Bson> {
private BsonDocument left;
public BsonMatcher(Bson left) {
this.left = left.toBsonDocument(BsonDocument.class, MongoClient.getDefaultCodecRegistry());
}
@Override
public boolean matches(Bson right) {
// compare as BsonDocument, since this does provide an equals()
return left.equals(right.toBsonDocument(BsonDocument.class, MongoClient.getDefaultCodecRegistry()));
}
}
请注意，您还需要将
assertEquals("Delete Successful", msg);更改为assertEquals("Successful Delete", msg);，因为deleteDocument返回"Successful Delete" :)