Checking es_vector:
1 1
1 3
2 0
es_vector with negative entry should fail.
Fromto not implemented.
Checking es_seq:
1 1
1 3
Checking eit_as_vector using seq:
2 3
Checking ess_seq using es_seq parameters:
1 1
1 3
Checking es_path:
3 4
2 3
es_path with negative entry should fail.
Checking es_type.