Function "ST_WITHIN" not found in Spring Boot Application using h2 In-Memory Database and Hibernate Spatial

In a Spring Boot application (h2 in-memory database + Hibernate Spatial) in a Junit test, I'm getting error "Function "ST_WITHIN" not found" for a "within" query

pom.xml:

<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
</dependency>
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-spatial</artifactId>
</dependency>       

test/resources/application.properties:

spring.datasource.url=jdbc:h2:mem:test;DB_CLOSE_DELAY=-1
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=va
spring.jpa.database=h2  
spring.jpa.database-platform=org.hibernate.spatial.dialect.h2geodb.GeoDBDialect

LocationRepository.java

@Query(value = "select l from Location l where within(l.position, :box) = true")
List<Location> findByPositionWithin(@Param("box") org.locationtech.jts.geom.Geometry box);

LocationEntity.java

@Column(columnDefinition = "GEOMETRY")
private org.locationtech.jts.geom.Point position;

Obviously, the alias ST_WITHIN is missing. Any ideas how to fix this?