old_contents: from __future__ import unicode_literals
  
  from spacy.tokens import Doc
  
  import pytest
  
  @pytest.mark.models
  def test_getitem(EN):
      tokens = EN(u'Give it back! He pleaded.')
      assert tokens[0].orth_ == 'Give'
      assert tokens[-1].orth_ == '.'
      with pytest.raises(IndexError):
          tokens[len(tokens)]
  
  
  @pytest.mark.models
  def test_serialize(EN):
      tokens = EN(u'Give it back! He pleaded.')
      packed = tokens.to_bytes()
      new_tokens = Doc(EN.vocab).from_bytes(packed)
      assert tokens.string == new_tokens.string
      assert [t.orth_ for t in tokens] == [t.orth_ for t in new_tokens]
      assert [t.orth for t in tokens] == [t.orth for t in new_tokens]
  
  
  @pytest.mark.models
  def test_serialize_whitespace(EN):
      tokens = EN(u' Give it back! He pleaded. ')
      packed = tokens.to_bytes()
      new_tokens = Doc(EN.vocab).from_bytes(packed)
      assert tokens.string == new_tokens.string
      assert [t.orth_ for t in tokens] == [t.orth_ for t in new_tokens]
      assert [t.orth for t in tokens] == [t.orth for t in new_tokens]
  
  
  def test_set_ents(EN):
      tokens = EN.tokenizer(u'I use goggle chrone to surf the web')
      assert len(tokens.ents) == 0
      tokens.ents = [(EN.vocab.strings['PRODUCT'], 2, 4)]
      assert len(list(tokens.ents)) == 1
      assert [t.ent_iob for t in tokens] == [0, 0, 3, 1, 0, 0, 0, 0]
      ent = tokens.ents[0]
      assert ent.label_ == 'PRODUCT'
      assert ent.start == 2
      assert ent.end == 4
  
new_contents: from __future__ import unicode_literals
  
  from spacy.tokens import Doc
  
  import pytest
  
  @pytest.mark.models
  def test_getitem(EN):
      tokens = EN(u'Give it back! He pleaded.')
      assert tokens[0].orth_ == 'Give'
      assert tokens[-1].orth_ == '.'
      with pytest.raises(IndexError):
          tokens[len(tokens)]
  
      span = tokens[1:1]
      assert not '/'.join(token.orth_ for token in span)
      span = tokens[1:4]
      assert '/'.join(token.orth_ for token in span) == 'it/back/!'
      with pytest.raises(ValueError):
          tokens[1:4:2]
      with pytest.raises(ValueError):
          tokens[1:4:-1]
  
  
  @pytest.mark.models
  def test_serialize(EN):
      tokens = EN(u'Give it back! He pleaded.')
      packed = tokens.to_bytes()
      new_tokens = Doc(EN.vocab).from_bytes(packed)
      assert tokens.string == new_tokens.string
      assert [t.orth_ for t in tokens] == [t.orth_ for t in new_tokens]
      assert [t.orth for t in tokens] == [t.orth for t in new_tokens]
  
  
  @pytest.mark.models
  def test_serialize_whitespace(EN):
      tokens = EN(u' Give it back! He pleaded. ')
      packed = tokens.to_bytes()
      new_tokens = Doc(EN.vocab).from_bytes(packed)
      assert tokens.string == new_tokens.string
      assert [t.orth_ for t in tokens] == [t.orth_ for t in new_tokens]
      assert [t.orth for t in tokens] == [t.orth for t in new_tokens]
  
  
  def test_set_ents(EN):
      tokens = EN.tokenizer(u'I use goggle chrone to surf the web')
      assert len(tokens.ents) == 0
      tokens.ents = [(EN.vocab.strings['PRODUCT'], 2, 4)]
      assert len(list(tokens.ents)) == 1
      assert [t.ent_iob for t in tokens] == [0, 0, 3, 1, 0, 0, 0, 0]
      ent = tokens.ents[0]
      assert ent.label_ == 'PRODUCT'
      assert ent.start == 2
      assert ent.end == 4
  
subject: Add Doc slicing tests