Better Testing with Testcontainers

Early in the process of writing applications, you have to decide how to run your integration tests. Will they hit a dedicated testing instance of Neo4j that is always running, or will you use the embedded instance?

There is a third option: starting a database before testing and stopping it after testing. Most of the time, this may require some manual scripting around test execution, but there is a much easier method: using testcontainers with a Neo4j module.

In this session, you'll learn how to start new instances of the database along with your tests whenever needed, take control of the lifetime of the container, and expose connection information needed for testing. With this, your testing infrastructure becomes much more portable and there is no need to share credentials of the test server in the future.

Transcript

1. 1
   Better Testing With Testcontainers
   

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2. 2
   Gerrit Meier
   ● Software Engineer at Neo4j
   ● Team Spring Data Neo4j and Neo4j OGM
   ●
   

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3. Software Testing
   

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4. Software Testing Integration testing
   

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5. Integration testing
   “Testing our application interacting
   with an external system.”
   -me
   

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6. Common setups
   6
   

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7. Common setups
   7
   Embedded
   

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8. Common setups
   8
   Embedded Local instance
   

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9. Common setups
   9
   Embedded Local instance
   Remote instance
   

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10. Common setups
    10
    Embedded Local instance
    Remote instance Docker
    

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11. 11
    Embedded
    

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12. 12
    Pros
    - Clean instance
    - Portable test suite
    - No side-effects from the
    outside
    Embedded
    

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13. 13
    Cons
    Pros
    - Dependency version
    - JVM version
    - Non-existing network
    - Memory allocation
    - Post-mortem debugging
    - Clean instance
    - Portable test suite
    - No side-effects from the
    outside
    Embedded
    

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14. 14
    Local instance
    

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15. 15
    Pros
    - Separation of application and
    database
    - Network
    - No version conflicts
    - Post-mortem debugging
    Local instance
    

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16. 16
    Cons
    Pros
    - Custom configuration
    - Setup needed for colleagues
    and CI
    - Lifecycle control on CI
    - Separation of application and
    database
    - Network
    - No version conflicts
    - Post-mortem debugging
    Local instance
    

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17. 17
    Remote instance a.k.a. the “Test instance”
    

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18. 18
    Pros
    - One time setup
    - Always on
    - No lifecycle management
    needed
    Remote instance a.k.a. the “Test instance”
    

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19. 19
    Cons
    Pros
    - Shared database state
    - Conflicting tests
    - Unexpected test failures
    - Post-mortem debugging
    - One time setup
    - Always on
    - No lifecycle management
    needed
    Remote instance a.k.a. the “Test instance”
    

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20. 20
    Docker
    

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21. 21
    Pros
    - Orchestration within test
    setup
    - Isolated testing
    Docker
    

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22. 22
    Cons
    Pros
    - Java API
    “command line”-style
    - Ready(?)
    - Orchestration within test
    setup
    - Isolated testing
    Docker
    

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23. Testcontainers
    - Fluent wrapper around Docker API
    - Support for a lot of systems out-of-the-box
    - Aware of readiness(!)
    - Seamless integration with JUnit (and Spock)
    - Networks of multiple containers
    - Copy data for testing
    

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24. 24
    Spring Boot
    Spring Data Neo4j
    JUnit 5
    

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25. 25
    MaterialIT.java @SpringBootTest
    class MaterialIT {
    private final MaterialRepository repository;
    private final Neo4jClient neo4jClient;
    @Autowired
    MaterialIT(MaterialRepository repository,
    Neo4jClient neo4jClient) {
    this.repository = repository;
    this.neo4jClient = neo4jClient;
    }
    }
    

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26. 26
    pom.xml
    Add Testcontainers
    
    org.testcontainers
    junit-jupiter
    1.17.6
    test
    
    

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27. 27
    MaterialIT.java @SpringBootTest
    class MaterialIT {
    static GenericContainer> container =
    new GenericContainer<>("neo4j:5")
    .withExposedPorts(7687)
    .withEnv("NEO4J_AUTH", "neo4j/verysecret");
    }
    

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28. 28
    MaterialIT.java @SpringBootTest
    class MaterialIT {
    static GenericContainer> container =
    new GenericContainer<>("neo4j:5")
    .withExposedPorts(7687)
    .withEnv("NEO4J_AUTH", "neo4j/verysecret");
    @BeforeAll
    static void startDatabase() {
    container.start();
    }
    }
    

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29. 29
    MaterialIT
    #testingProperties
    @DynamicPropertySource
    static void testingProperties(
    DynamicPropertyRegistry registry) {
    registry.add("spring.neo4j.uri",
    () ->
    "neo4j://" + container.getHost() +
    ":" + container.getMappedPort(7687));
    registry.add("spring.neo4j.authentication.username",
    () -> "neo4j");
    registry.add("spring.neo4j.authentication.password",
    () -> "verysecret");
    }
    

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30. 30
    MaterialIT.java @SpringBootTest
    @Testcontainers
    class MaterialIT {
    @Container
    static GenericContainer> container =
    new GenericContainer<>("neo4j:5")
    .withExposedPorts(7687)
    .withEnv("NEO4J_AUTH", "neo4j/verysecret");
    }
    

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31. Testcontainers Neo4j
    - Neo4j readiness aware
    - Simplified env parameters for configuration
    - Exposes Bolt and HTTP port as default
    - Neo4j specific API
    - Admin user setup
    - Connection related information
    - Neo4j Labs Plugin activation
    

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32. 32
    pom.xml
    Add Testcontainers
    
    org.testcontainers
    neo4j
    1.17.6
    test
    
    

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33. 33
    MaterialIT.java @SpringBootTest
    @Testcontainers
    class MaterialIT {
    @Container
    static Neo4jContainer> container =
    new Neo4jContainer<>("neo4j:5")
    .withAdminPassword("verysecret")
    }
    

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34. 34
    MaterialIT
    #testingProperties
    @DynamicPropertySource
    static void testingProperties(
    DynamicPropertyRegistry registry) {
    registry.add("spring.neo4j.uri",
    container::getBoltUrl);
    registry.add("spring.neo4j.authentication.username",
    () -> "neo4j");
    registry.add("spring.neo4j.authentication.password",
    container::getAdminPassword);
    }
    

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35. 35
    MaterialIT
    #pluginCall
    void pluginCall() {
    String apocVersion = neo4jClient
    .query("RETURN apoc.version()")
    .fetchAs(String.class)
    .one().get();
    Assertions.assertThat(apocVersion)
    .isEqualTo("5.1.0");
    }
    

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36. 36
    MaterialIT
    #pluginCall
    void pluginCall() {
    String apocVersion = neo4jClient
    .query("RETURN apoc.version()")
    .fetchAs(String.class)
    .one().get();
    Assertions.assertThat(apocVersion)
    .isEqualTo("5.1.0");
    }
    Unknown function 'apoc.version'
    

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37. 37
    MaterialIT.java @SpringBootTest
    @Testcontainers
    class MaterialIT {
    @Container
    static Neo4jContainer> container =
    new Neo4jContainer<>("neo4j:5")
    .withAdminPassword("verysecret")
    .withLabsPlugins(Neo4jLabsPlugin.APOC)
    }
    

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38. 38
    MaterialIT
    #pluginCall
    void pluginCall() {
    String apocVersion = neo4jClient
    .query("RETURN apoc.version()")
    .fetchAs(String.class)
    .one().get();
    Assertions.assertThat(apocVersion)
    .isEqualTo("5.1.0");
    }
    

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39. 39
    MaterialIT
    #pluginCall
    void pluginCall() {
    String apocVersion = neo4jClient
    .query("RETURN apoc.version()")
    .fetchAs(String.class)
    .one().get();
    Assertions.assertThat(apocVersion)
    .isEqualTo("5.1.0");
    }
    

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40. Performance
    (experimental) Feature: Reusable Testcontainers
    

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41. Performance
    (experimental) Feature: Reusable Testcontainers
    Neo4jContainer> container = new Neo4jContainer<>("neo4j:5")
    .withAdminPassword("verysecret")
    .withReuse(true)
    

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42. Performance
    (experimental) Feature: Reusable Testcontainers
    testcontainers.reuse.enable=true
    ~/.testcontainers.properties
    Neo4jContainer> container = new Neo4jContainer<>("neo4j:5")
    .withAdminPassword("verysecret")
    .withReuse(true)
    

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43. Conclusion
    ● Reproducible and portable tests
    ● No manual lifecycle management (JUnit extension)
    ● For more performance: reusable containers
    ● Covers more than just Neo4j
    ● Create Test Matrix with ease
    

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44. 44
    Create data Neo4j-Migrations
    Neo4j Migrations: The Lean Way of Applying Database
    Refactorings to Neo4j
    Michael Simons
    15:40 (UTC)
    16:40 (CET)
    

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45. 45
    ● Testcontainers:
    https://www.testcontainers.org/
    ● Reusable Testcontainers:
    ● https://foojay.io/today/faster-integration-tests-
    with-reusable-testcontainers/
    ● me:
    @meistermeier(@mastodon.social)
    Thank
    you!
    ❤
    

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