Testcontainers将MongoDB服务器端口Map到您机器上的随机端口。这就是为什么不能在属性文件中硬编码spring.data.mongodb.uri=mongodb://127.0.0.1:27017/test。
JUnit 5和Sping Boot 〉= 2.2.6的基本设置如下所示

@Testcontainers
public class MongoDbIT {

  @Container
  public static MongoDBContainer container = new MongoDBContainer(DockerImageName.parse("mongo:5"));

  @DynamicPropertySource
  static void mongoDbProperties(DynamicPropertyRegistry registry) {
    registry.add("spring.data.mongodb.uri", container::getReplicaSetUrl);
  }

}

如果您使用的是不同的JUnit或Sping Boot 版本，请查看以下correct Testcontainers setup指南。

下面的完整autowired示例在Spring 6.0.X中运行良好。
它正确地绑定了yout Repository并设置了MongoClient

@DataMongoTest
@Testcontainers
public class TestContainersMongo {

    @Autowired
    UserRepository userRepository;

    @Container
    static MongoDBContainer mongoDBContainer = new MongoDBContainer(DockerImageName.parse("mongo:4.0.10"));

    @DynamicPropertySource
    static void setProperties(DynamicPropertyRegistry registry) {
        registry.add("spring.data.mongodb.uri", () -> mongoDBContainer.getReplicaSetUrl("embedded"));
    }

    @AfterEach
    void cleanUp() {
        userRepository.deleteAll();
    }

    @Test
    void shouldReturnListOfCustomerWithMatchingRate() {
        userRepository.insert(UserGenerator.generate(12));

        List<User> customers = userRepository.findAll();

        assertThat(customers).hasSize(12);
    }
}