[JAVA] Testing JPA entities and repositories using Spring Boot @DataJpaTest

What is @DataJpaTest?

Annotations for using Auto Configuratin for testing entities and repositories. You can easily write a test by using this. It has the following features. -Load the class with @Entitiy and @Repository into ApplicationContext. Classes with other @Service etc. are not loaded. -Rollback the transaction for each test (@Test). Transaction control can be changed. -Use in-memory DB in the test

In addition, TestEntityManager is prepared for manipulating test data in the test class.

See the official documentation for details. 43.3.11 Auto-configured Data JPA Tests

Example

Add a dependency to build.gradle to use the H2 database when testing with JPA.

build.gradle

dependencies {

・ ・ ・
	compile('org.springframework.boot:spring-boot-starter-data-jpa')
	testCompile('org.springframework.boot:spring-boot-starter-test')
	testCompile group: 'com.h2database', name: 'h2', version: '1.4.197'
}

As a sample, create an entity and repository that handles book information as shown below. The following example is written in Kotlin, but the description method is the same in Java.

@Entity
@Table(name = "book")
data class Book(

        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY) //ID is automatically generated
        @Column(name = "id")
        var id: Long = 0,

        @Column(name = "title")
        var title: String = "",

        @Column(name = "author")
        var author: String = "",

        @Column
        var price: Long = 0
)

Create the following repository for the above entity.

@Repository
interface BookRepository: JpaRepository<Book, Long> {

    //A method that returns a list of books with the specified author in ascending order of price
    fun findAllByAuthorOrderByPrice(author: String): List<Book>
}

Create a test class. By using TestEntityManager, test data can be stored in DB without using Repository.

import org.assertj.core.api.Assertions.assertThat
import org.junit.Test
import org.junit.runner.RunWith
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest
import org.springframework.boot.test.autoconfigure.orm.jpa.TestEntityManager
import org.springframework.test.context.junit4.SpringRunner

@RunWith(SpringRunner::class)
@DataJpaTest
class BookRepositoryTest {

    @Autowired
    private lateinit var testEntityManager: TestEntityManager

    @Autowired
    private lateinit var bookRepository: BookRepository

    @Test
    fun test() {

        //Test data creation
        testEntityManager.persist(Book(title = "title1", author = "author1", price = 102))
        testEntityManager.persist(Book(title = "title2", author = "author1", price = 101))
        testEntityManager.persist(Book(title = "title3", author = "author2", price = 104))
        testEntityManager.persist(Book(title = "title4", author = "author2", price = 103))

        val foundBooks = bookRepository.findAllByAuthorOrderByPrice("author1")

        //There are two books for author1
        assertThat(foundBooks).size().isEqualTo(2)

        //Search results are in ascending order of price, so title2,Should be in the order of title1
        // title1
        assertThat(foundBooks[0].id).isEqualTo(2)
        assertThat(foundBooks[0].title).isEqualTo("title2")
        assertThat(foundBooks[0].author).isEqualTo("author1")
        assertThat(foundBooks[0].price).isEqualTo(101)

        // title2
        assertThat(foundBooks[1].id).isEqualTo(1)
        assertThat(foundBooks[1].title).isEqualTo("title1")
        assertThat(foundBooks[1].author).isEqualTo("author1")
        assertThat(foundBooks[1].price).isEqualTo(102)

    }
}