Spring JPA Specification API unit tests

I am trying to write unit tests for a class that returns a lamda of Specification object. I'm unable to get the line coverage using Mockito and Junit5

final class StudentRecordsSpecification{
public static Specification<ClassesForFall> findByStudentRegisteredforClasses(Student student){
    return(fallClasses, criteriaQuery, criteriaBuilder) ->{
         List<Predicate> sqlCriteria = new ArrayList<>();
         sqlCriteria.add(criteriaBuilder.equal(fallClasses.get("profile"), student.getProfile()));
         if (!student.getSubjectTeachers().isEmpty()) {
            student
              .getSubjectTeachers()
              .forEach(
                (subject, teacher) ->
                sqlCriteria.add(criteriaBuilder.equal(fallClasses.get(subject), teacher)));
        }
         criteriaQuery.where(criteriaBuilder.and(sqlCriteria.toArray(new Predicate[] {})));
      return criteriaQuery.getRestriction();
    }
  }
}

when running the class under test the compiler exits with out checking anything. Not sure how to mock the objects of ClassesForFall, criteriaBuilder, criteriaQuery