@Test
public void delete_members_by_group_id() {
UserDto user1 = dbTester.users().insertUser();
UserDto user2 = dbTester.users().insertUser();
GroupDto group1 = dbTester.users().insertGroup();
GroupDto group2 = dbTester.users().insertGroup();
dbTester.users().insertMember(group1, user1);
dbTester.users().insertMember(group1, user2);
dbTester.users().insertMember(group2, user1);
dbTester.users().insertMember(group2, user2);
underTest.deleteByGroupId(dbTester.getSession(), group1.getId());
dbTester.getSession().commit();
assertThat(dbTester.getDbClient().groupMembershipDao().selectGroupIdsByUserId(dbTester.getSession(), user1.getId())).containsOnly(group2.getId());
assertThat(dbTester.getDbClient().groupMembershipDao().selectGroupIdsByUserId(dbTester.getSession(), user2.getId())).containsOnly(group2.getId());
}