在 Java 中使用 Mockito 模拟 MongoDB 的 DeleteResult
Mocking DeleteResult of MongoDB using Mockito in Java
下面的单元测试无法为正在测试的 Java 代码模拟 DeleteResult。获取 NullPointerException。我是 运行 JUnit 测试。是不是和delete语句中的Filters有关？
@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，被测试的代码只需要删除一条记录，如果没有这样的记录，return一个警告。下面正在测试的方法是 DBCollection class:
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.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.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.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access[=14=]0(ParentRunner.java:58)
at org.junit.runners.ParentRunner.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)
有什么问题吗？
这里的问题是这个期望：
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 所以当 Mockito 试图确定它是否应该 return 来自你 deleteDocument 中的 collectionsDocs.deleteOne 调用的东西时它不能匹配过滤器参数，因此它确定 collectionsDocs.deleteOne return 什么都没有。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);
你的测试将通过 - 尽管对过滤器的特异性较低 - 如果你表达 deleteOne 期望是这样的：
Mockito.when(mockCollection.deleteOne(any(Bson.class))).thenReturn(mockDeleteResult);
或者，您可以使用自定义匹配器对 Bson 应用您自己的相等检查。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 returns "Successful Delete" :)
下面的单元测试无法为正在测试的 Java 代码模拟 DeleteResult。获取 NullPointerException。我是 运行 JUnit 测试。是不是和delete语句中的Filters有关？
@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，被测试的代码只需要删除一条记录，如果没有这样的记录，return一个警告。下面正在测试的方法是 DBCollection class:
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.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.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.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access[=14=]0(ParentRunner.java:58)
at org.junit.runners.ParentRunner.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)
有什么问题吗？
这里的问题是这个期望：
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 所以当 Mockito 试图确定它是否应该 return 来自你 deleteDocument 中的 collectionsDocs.deleteOne 调用的东西时它不能匹配过滤器参数，因此它确定 collectionsDocs.deleteOne return 什么都没有。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);
你的测试将通过 - 尽管对过滤器的特异性较低 - 如果你表达 deleteOne 期望是这样的：
Mockito.when(mockCollection.deleteOne(any(Bson.class))).thenReturn(mockDeleteResult);
或者，您可以使用自定义匹配器对 Bson 应用您自己的相等检查。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 returns "Successful Delete" :)