java h2 in-memory database error: Table not found

Have these properties in your application.properties file in the src/test/resources folder:

spring.jpa.generate-ddl=true

spring.jpa.hibernate.ddl-auto=create

This has to be over-ridden because it's not kept create rather kept none or validate after the first ddl creation.

Table was not found, because there was an error at the start when trying to create it. And the error was due to the fact, that one of the ClassifierGroupEntity fields was named 'order', which is one of reserved words in SQL, and thus the generated SQL statement by Spring was syntactically incorrect.