How to test Spring Data repositories

Question

I want a repository  say  UserRepository  created with the help of Spring Data  I am new to spring-data  but not to spring  and I use this tutorial  My choice of technologies for dealing with the database is JPA 2 1 and Hibernate  The problem is that I am clueless as to how to write unit tests for such a repository   Let s take create   method for instance  As I am working test-first  I am supposed to write a unit test for it - and that s where I bump into three problems    First  how do I inject a mock of an EntityManager into the non-existing implementation of a UserRepository interface  Spring Data would generate an implementation based on this interface   public interface UserRepository extends CrudRepository lt User  Long gt       However  I don t know how to force it to use an EntityManager mock and other mocks - if I had written the implementation myself  I would probably have a setter method for EntityManager  allowing me to use my mock for the unit test   As for actual database connectivity  I have a JpaConfiguration class  annotated with  Configuration and  EnableJpaRepositories  which programmatically defines beans for DataSource  EntityManagerFactory  EntityManager etc  - but repositories should be test-friendly and allow for overriding these things   Second  should I test for interactions  It is hard for me to figure out what methods of EntityManager and Query are supposed to be called  akin to that verify entityManager  createNamedQuery anyString    getResultList      since it isn t me who is writing the implementation  Third  am I supposed to unit-test the Spring-Data-generated methods in the first place  As I know  the third-party library code is not supposed to be unit-tested - only the code the developers write themselves is supposed to be unit-tested  But if that s true  it still brings the first question back to the scene  say  I have a couple of custom methods for my repository  for which I will be writing implementation  how do I inject my mocks of EntityManager and Query into the final  generated repository    Note  I will be test-driving my repositories using both the integration and the unit tests  For my integration tests I am using an HSQL in-memory database  and I am obviously not using a database for unit tests   And probably the fourth question  is it correct to test the correct object graph creation and object graph retrieval in the integration tests  say  I have a complex object graph defined with Hibernate    Update  today I ve continued experimenting with mock injection - I created a static inner class to allow for mock injection     RunWith SpringJUnit4ClassRunner class   ContextConfiguration  Transactional  TransactionConfiguration defaultRollback   true  public class UserRepositoryTest     Configuration  EnableJpaRepositories basePackages    com anything repository   static class TestConfiguration         Bean     public EntityManagerFactory entityManagerFactory             return mock EntityManagerFactory class               Bean     public EntityManager entityManager             EntityManager entityManagerMock   mock EntityManager class             when entityManagerMock getMetamodel    thenReturn mock Metamodel class            when entityManagerMock getMetamodel    thenReturn mock MetamodelImpl class            return entityManagerMock              Bean     public PlatformTransactionManager transactionManager             return mock JpaTransactionManager class              Autowired private UserRepository userRepository    Autowired private EntityManager entityManager    Test public void shouldSaveUser         User user   new UserBuilder   build        userRepository save user       verify entityManager createNamedQuery anyString    executeUpdate            However  running this test gives me the following stacktrace   java lang IllegalStateException  Failed to load ApplicationContext at org springframework test context CacheAwareContextLoaderDelegate loadContext CacheAwareContextLoaderDelegate java 99  at org springframework test context DefaultTestContext getApplicationContext DefaultTestContext java 101  at org springframework test context support DependencyInjectionTestExecutionListener injectDependencies DependencyInjectionTestExecutionListener java 109  at org springframework test context support DependencyInjectionTestExecutionListener prepareTestInstance DependencyInjectionTestExecutionListener java 75  at org springframework test context TestContextManager prepareTestInstance TestContextManager java 319  at org springframework test context junit4 SpringJUnit4ClassRunner createTest SpringJUnit4ClassRunner java 212  at org springframework test context junit4 SpringJUnit4ClassRunner 1 runReflectiveCall SpringJUnit4ClassRunner java 289  at org junit internal runners model ReflectiveCallable run ReflectiveCallable java 12  at org springframework test context junit4 SpringJUnit4ClassRunner methodBlock SpringJUnit4ClassRunner java 291  at org springframework test context junit4 SpringJUnit4ClassRunner runChild SpringJUnit4ClassRunner java 232  at org springframework test context junit4 SpringJUnit4ClassRunner runChild SpringJUnit4ClassRunner java 89  at org junit runners ParentRunner 3 run ParentRunner java 238  at org junit runners ParentRunner 1 schedule ParentRunner java 63  at org junit runners ParentRunner runChildren ParentRunner java 236  at org junit runners ParentRunner access 000 ParentRunner java 53  at org junit runners ParentRunner 2 evaluate ParentRunner java 229  at org springframework test context junit4 statements RunBeforeTestClassCallbacks evaluate RunBeforeTestClassCallbacks java 61  at org springframework test context junit4 statements RunAfterTestClassCallbacks evaluate RunAfterTestClassCallbacks java 71  at org junit runners ParentRunner run ParentRunner java 309  at org springframework test context junit4 SpringJUnit4ClassRunner run SpringJUnit4ClassRunner java 175  at org junit runner JUnitCore run JUnitCore java 160  at com intellij junit4 JUnit4IdeaTestRunner startRunnerWithArgs JUnit4IdeaTestRunner java 77  at com intellij rt execution junit JUnitStarter prepareStreamsAndStart JUnitStarter java 195  at com intellij rt execution junit JUnitStarter main JUnitStarter java 63  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  org springframework beans factory BeanCreationException  Error creating bean with name  userRepository   Error setting property values  nested exception is org springframework beans PropertyBatchUpdateException  nested PropertyAccessExceptions  1  are  PropertyAccessException 1  org springframework beans MethodInvocationException  Property  entityManager  threw exception  nested exception is java lang IllegalArgumentException  JPA Metamodel must not be null      at org springframework beans factory support AbstractAutowireCapableBeanFactory applyPropertyValues AbstractAutowireCapableBeanFactory java 1493      at org springframework beans factory support AbstractAutowireCapableBeanFactory populateBean AbstractAutowireCapableBeanFactory java 1197      at org springframework beans factory support AbstractAutowireCapableBeanFactory doCreateBean AbstractAutowireCapableBeanFactory java 537      at org springframework beans factory support AbstractAutowireCapableBeanFactory createBean AbstractAutowireCapableBeanFactory java 475      at org springframework beans factory support AbstractBeanFactory 1 getObject AbstractBeanFactory java 304      at org springframework beans factory support DefaultSingletonBeanRegistry getSingleton DefaultSingletonBeanRegistry java 228      at org springframework beans factory support AbstractBeanFactory doGetBean AbstractBeanFactory java 300      at org springframework beans factory support AbstractBeanFactory getBean AbstractBeanFactory java 195      at org springframework beans factory support DefaultListableBeanFactory preInstantiateSingletons DefaultListableBeanFactory java 684      at org springframework context support AbstractApplicationContext finishBeanFactoryInitialization AbstractApplicationContext java 760      at org springframework context support AbstractApplicationContext refresh AbstractApplicationContext java 482      at org springframework test context support AbstractGenericContextLoader loadContext AbstractGenericContextLoader java 121      at org springframework test context support AbstractGenericContextLoader loadContext AbstractGenericContextLoader java 60      at org springframework test context support AbstractDelegatingSmartContextLoader delegateLoading AbstractDelegatingSmartContextLoader java 100      at org springframework test context support AbstractDelegatingSmartContextLoader loadContext AbstractDelegatingSmartContextLoader java 250      at org springframework test context CacheAwareContextLoaderDelegate loadContextInternal CacheAwareContextLoaderDelegate java 64      at org springframework test context CacheAwareContextLoaderDelegate loadContext CacheAwareContextLoaderDelegate java 91          28 more Caused by  org springframework beans PropertyBatchUpdateException  nested PropertyAccessExceptions  1  are  PropertyAccessException 1  org springframework beans MethodInvocationException  Property  entityManager  threw exception  nested exception is java lang IllegalArgumentException  JPA Metamodel must not be null      at org springframework beans AbstractPropertyAccessor setPropertyValues AbstractPropertyAccessor java 108      at org springframework beans AbstractPropertyAccessor setPropertyValues AbstractPropertyAccessor java 62      at org springframework beans factory support AbstractAutowireCapableBeanFactory applyPropertyValues AbstractAutowireCapableBeanFactory java 1489          44 more

User · Answer

In the last version of spring boot 2 1 1 RELEASE  it is simple as     RunWith SpringRunner class   SpringBootTest classes   SampleApplication class  public class CustomerRepositoryIntegrationTest         Autowired     CustomerRepository repository        Test     public void myTest   throws Exception            Customer customer   new Customer            customer setId 100l           customer setFirstName  John            customer setLastName  Wick             repository save customer            List lt   gt  queryResult   repository findByLastName  Wick             assertFalse queryResult isEmpty             assertNotNull queryResult get 0              Complete code   https   github com jrichardsz spring-boot-templates blob master 003-hql-database-with-integration-test src test java test CustomerRepositoryIntegrationTest java

User · Answer

When you really want to write an i-test for a spring data repository you can do it like this    RunWith SpringRunner class   DataJpaTest  EnableJpaRepositories basePackageClasses   WebBookingRepository class   EntityScan basePackageClasses   WebBooking class  public class WebBookingRepositoryIntegrationTest         Autowired     private WebBookingRepository repository        Test     public void testSaveAndFindAll             WebBooking webBooking   new WebBooking            webBooking setUuid  some uuid            webBooking setItems Arrays asList new WebBookingItem              repository save webBooking            Iterable lt WebBooking gt  findAll   repository findAll             assertThat findAll  hasSize 1           webBooking setId 1L           assertThat findAll  containsOnly webBooking             To follow this example you have to use these dependencies    lt dependency gt       lt groupId gt com h2database lt  groupId gt       lt artifactId gt h2 lt  artifactId gt       lt version gt 1 4 197 lt  version gt       lt scope gt test lt  scope gt   lt  dependency gt   lt dependency gt       lt groupId gt junit lt  groupId gt       lt artifactId gt junit lt  artifactId gt       lt version gt 4 12 lt  version gt       lt scope gt test lt  scope gt   lt  dependency gt   lt dependency gt       lt groupId gt org assertj lt  groupId gt       lt artifactId gt assertj-core lt  artifactId gt       lt version gt 3 9 1 lt  version gt       lt scope gt test lt  scope gt   lt  dependency gt   lt dependency gt       lt groupId gt org springframework boot lt  groupId gt       lt artifactId gt spring-boot-starter-data-jpa lt  artifactId gt   lt  dependency gt   lt dependency gt       lt groupId gt org springframework boot lt  groupId gt       lt artifactId gt spring-boot-starter-test lt  artifactId gt       lt scope gt test lt  scope gt   lt  dependency gt

User · Answer

tl dr  To make it short - there s no way to unit test Spring Data JPA repositories reasonably for a simple reason  it s way to cumbersome to mock all the parts of the JPA API we invoke to bootstrap the repositories  Unit tests don t make too much sense here anyway  as you re usually not writing any implementation code yourself  see the below paragraph on custom implementations  so that integration testing is the most reasonable approach   Details  We do quite a lot of upfront validation and setup to make sure you can only bootstrap an app that has no invalid derived queries etc    We create and cache CriteriaQuery instances for derived queries to make sure the query methods do not contain any typos  This requires working with the Criteria API as well as the meta model  We verify manually defined queries by asking the EntityManager to create a Query instance for those  which effectively triggers query syntax validation   We inspect the Metamodel for meta-data about the domain types handled to prepare is-new checks etc    All stuff that you d probably defer in a hand-written repository which might cause the application to break at runtime  due to invalid queries etc     If you think about it  there s no code you write for your repositories  so there s no need to write any unittests  There s simply no need to as you can rely on our test base to catch basic bugs  if you still happen to run into one  feel free to raise a ticket   However  there s definitely need for integration tests to test two aspects of your persistence layer as they are the aspects that related to your domain     entity mappings  query semantics  syntax is verified on each bootstrap attempt anyway     Integration tests  This is usually done by using an in-memory database and test cases that bootstrap a Spring ApplicationContext usually through the test context framework  as you already do   pre-populate the database  by inserting object instances through the EntityManager or repo  or via a plain SQL file  and then execute the query methods to verify the outcome of them   Testing custom implementations  Custom implementation parts of the repository are written in a way that they don t have to know about Spring Data JPA  They are plain Spring beans that get an EntityManager injected  You might of course wanna try to mock the interactions with it but to be honest  unit-testing the JPA has not been a too pleasant experience for us as well as it works with quite a lot of indirections  EntityManager -  CriteriaBuilder  CriteriaQuery etc   so that you end up with mocks returning mocks and so on

User · Answer

I solved this by using this way -        RunWith SpringRunner class       EnableJpaRepositories basePackages   com path repositories         EntityScan basePackages   com model         TestPropertySource  classpath application properties        ContextConfiguration classes    ApiTestConfig class SaveActionsServiceImpl class       public class SaveCriticalProcedureTest             Autowired         private SaveActionsService saveActionsService

User · Answer

With JUnit5 and  DataJpaTest test will look like  kotlin code     DataJpaTest  ExtendWith value    SpringExtension  class   class ActivityJpaTest         Autowired     lateinit var entityManager  TestEntityManager       Autowired     lateinit var myEntityRepository  MyEntityRepository       Test     fun shouldSaveEntity                when         val savedEntity   myEntityRepository save MyEntity 1   test               then          Assertions assertNotNull entityManager find MyEntity  class java  savedEntity id             You could use TestEntityManager from org springframework boot test autoconfigure orm jpa TestEntityManager package in order to validate entity state

User · Answer

If you re using Spring Boot  you can simply use  SpringBootTest to load in your ApplicationContext  which is what your stacktrace is barking at you about    This allows you to autowire in your spring-data repositories   Be sure to add  RunWith SpringRunner class  so the spring-specific annotations are picked up    RunWith SpringRunner class   SpringBootTest public class OrphanManagementTest       Autowired   private UserRepository userRepository      Test   public void saveTest         User user   new User  Tom        userRepository save user       Assert assertNotNull userRepository findOne  Tom             You can read more about testing in spring boot in their docs

User · Answer

With Spring Boot   Spring Data it has become quite easy    RunWith SpringRunner class   DataJpaTest public class MyRepositoryTest         Autowired     MyRepository subject        Test     public void myTest   throws Exception           subject save new MyEntity               The solution by  heez brings up the full context  this only bring up what is needed for JPA Transaction to work  Note that the solution above will bring up a in memory test database given that one can be found on the classpath

User · Answer

This may come a bit too late  but I have written something for this very purpose  My library will mock out the basic crud repository methods for you as well as interpret most of the functionalities of your query methods  You will have to inject functionalities for your own native queries  but the rest are done for you   Take a look   https   github com mmnaseri spring-data-mock  UPDATE  This is now in Maven central and in pretty good shape

[unit-testing] How to test Spring Data repositories?

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