def test_cli_converters_conllu_empty_heads_ner():
    """
    conllu_to_docs should not raise an exception if the HEAD column contains an
    underscore
    """
    input_data = """
1	[	_	PUNCT	-LRB-	_	_	punct	_	_
2	This	_	DET	DT	_	_	det	_	_
3	killing	_	NOUN	NN	_	_	nsubj	_	_
4	of	_	ADP	IN	_	_	case	_	_
5	a	_	DET	DT	_	_	det	_	_
6	respected	_	ADJ	JJ	_	_	amod	_	_
7	cleric	_	NOUN	NN	_	_	nmod	_	_
8	will	_	AUX	MD	_	_	aux	_	_
9	be	_	AUX	VB	_	_	aux	_	_
10	causing	_	VERB	VBG	_	_	root	_	_
11	us	_	PRON	PRP	_	_	iobj	_	_
12	trouble	_	NOUN	NN	_	_	dobj	_	_
13	for	_	ADP	IN	_	_	case	_	_
14	years	_	NOUN	NNS	_	_	nmod	_	_
15	to	_	PART	TO	_	_	mark	_	_
16	come	_	VERB	VB	_	_	acl	_	_
17	.	_	PUNCT	.	_	_	punct	_	_
18	]	_	PUNCT	-RRB-	_	_	punct	_	_
"""
    docs = list(conllu_to_docs(input_data))
    # heads are all 0
    assert not all([t.head.i for t in docs[0]])
    # NER is unset
    assert not docs[0].has_annotation("ENT_IOB")

    conllu_to_docs should not raise an exception if the HEAD column contains an
    underscore
    
spacy/tests/test_cli.py