old_contents: import pytest
  
  from tsstats.client import Client, Clients
  
  
  @pytest.fixture(scope='module')
  def clients():
      clients = Clients()
      cl1 = Client('1')
      cl2 = Client('2')
      clients += cl1
      clients += cl2
      uidcl1 = Client('UID1')
      uidcl2 = Client('UID2')
      clients += uidcl1
      clients += uidcl2
      return (clients, cl1, cl2, uidcl1, uidcl2)
  
  
  def test_client_get(clients):
      clients, cl1, cl2, uidcl1, uidcl2 = clients
      assert clients['1'] == cl1
      assert clients['2'] == cl2
      assert clients['UID1'] == uidcl1
      assert clients['UID2'] == uidcl2
      with pytest.raises(KeyError):
          clients['3']
          clients['UID3']
  
  
  def test_client_repr(clients):
      clients, _, _, _, _ = clients
      assert str(clients['1']) == '<1, None>'
      assert str(clients['2']) == '<2, None>'
      assert str(clients['UID1']) == '<UID1, None>'
      assert str(clients['UID2']) == '<UID2, None>'
  
  
  def test_clients_iter(clients):
      clients, cl1, cl2, uidcl1, uidcl2 = clients
      client_list = list(iter(clients))
      assert cl1 in client_list
      assert cl2 in client_list
      assert uidcl1 in client_list
      assert uidcl2 in client_list
  
  
  def test_clients_delete(clients):
      clients, cl1, _, _, _ = clients
      del clients['1']
      assert cl1 not in clients
  
new_contents: import pytest
  
  from tsstats.client import Client, Clients
  
  
  @pytest.fixture(scope='module')
  def clients():
      clients = Clients()
      cl1 = Client('1')
      cl2 = Client('2')
      clients += cl1
      clients += cl2
      uidcl1 = Client('UID1')
      uidcl2 = Client('UID2')
      clients += uidcl1
      clients += uidcl2
      return (clients, cl1, cl2, uidcl1, uidcl2)
  
  
  def test_client_get(clients):
      clients, cl1, cl2, uidcl1, uidcl2 = clients
      assert clients['1'] == cl1
      assert clients['2'] == cl2
      assert clients['UID1'] == uidcl1
      assert clients['UID2'] == uidcl2
      with pytest.raises(KeyError):
          clients['3']
          clients['UID3']
  
  
  def test_client_repr(clients):
      clients, _, _, _, _ = clients
      assert str(clients['1']) == '<1, None>'
      assert str(clients['2']) == '<2, None>'
      assert str(clients['UID1']) == '<UID1, None>'
      assert str(clients['UID2']) == '<UID2, None>'
  
  
  def test_client_nick(clients):
      _, cl1, _, _, _ = clients
      assert cl1.nick is None
      assert not cl1.nick_history
      cl1.nick = 'Client1'
      assert cl1.nick == 'Client1'
      assert None not in cl1.nick_history
      cl1.nick = 'NewClient1'
      assert cl1.nick == 'NewClient1'
      assert 'Client1' in cl1.nick_history
  
  
  def test_clients_iter(clients):
      clients, cl1, cl2, uidcl1, uidcl2 = clients
      client_list = list(iter(clients))
      assert cl1 in client_list
      assert cl2 in client_list
      assert uidcl1 in client_list
      assert uidcl2 in client_list
  
  
  def test_clients_delete(clients):
      clients, cl1, _, _, _ = clients
      del clients['1']
      assert cl1 not in clients
  
subject: Add test for Client.nick-property