"test" --- Pacote de Testes de Regressão do Python
**************************************************

Nota:

  O pacote "test" é apenas para uso interno do Python. O mesmo está
  sendo documentado para o benefício dos principais desenvolvedores do
  Python. Qualquer uso deste pacote fora da biblioteca padrão do
  Python é desencorajado, pois, o código mencionado aqui pode ser
  alterado ou removido sem aviso prévio entre as versões do Python.

======================================================================

O pacote "test" contém todos os testes de regressão do Python, bem
como os módulos "test.support" e "test.regrtest". "test.support" é
utilizado para aprimorar seus testes enquanto o "test.regrtest"
direciona a suite de testes.

Cada módulo no pacote "test" cujo nome começa com "test_" é um
conjunto de testes para um módulo ou recurso específico. Todos os
novos testes devem ser escritos usando o módulo "unittest" ou
"doctest". Alguns testes mais antigos são escritos usando um estilo de
teste "tradicional" que compara a saída impressa a "sys.stdout". Este
estilo de teste foi considerado descontinuado.

Ver também:

  Módulo "unittest"
     Escrevendo testes de regressão PyUnit.

  Módulo "doctest"
     Testes embutidos em Strings da documentação.


Escrever testes unitários para o pacote "test"
==============================================

É preferível que os testes que usam o módulo "unittest" sigam algumas
diretrizes. Uma é nomear o módulo de teste iniciando-o com "test_" e
termine com o nome do módulo que está sendo testado. Os métodos de
teste no módulo de teste deve começar com "test_" e terminar com uma
descrição do que o método está testando. Isso é necessário para que os
métodos sejam reconhecidos pelo driver de teste como métodos de teste.
Além disso, na string de documentação para o método deve ser incluído.
Um comentário (como os "# Tests function returns only True or False")
deve ser usado para fornecer documentação para testar métodos. Isso é
feito porque as strings de documentação são impressas se existem e,
portanto, qual teste está sendo executado não é indicado.

Um boilerplate básico é muitas vezes usado:

   import unittest
   from test import support

   class MyTestCase1(unittest.TestCase):

       # Only use setUp() and tearDown() if necessary

       def setUp(self):
           ... code to execute in preparation for tests ...

       def tearDown(self):
           ... code to execute to clean up after tests ...

       def test_feature_one(self):
           # Test feature one.
           ... testing code ...

       def test_feature_two(self):
           # Test feature two.
           ... testing code ...

       ... more test methods ...

   class MyTestCase2(unittest.TestCase):
       ... same structure as MyTestCase1 ...

   ... more test classes ...

   if __name__ == '__main__':
       unittest.main()

Este padrão de código permite que o conjunto de testes seja executado
pelo "test.regrtest", por conta própria, como um script que suporte o
"unittest" CLI, ou através do "python -m unittest" CLI.

O objetivo do teste de regressão é tentar quebrar o código. Isso leva
a algumas diretrizes que devemos seguir:

* O conjunto de testes deve exercitar todas as classes, funções e
  constantes. Isso inclui não apenas a API externa que deve ser
  apresentada ao mundo exterior, mas também o código "privado".

* Os testes de Whitebox (que examinam o código que está sendo testado
  quando os testes estão sendo gravados) são preferidos. O teste
  Blackbox (que testa apenas a interface do público de usuário) não é
  completo o suficiente para garantir que todos os casos de limite e
  extremos sejam testados.

* Certifique-se de que todos os valores possíveis sejam testados,
  incluindo os inválidos. Isso garante que não apenas todos os valores
  válidos são aceitos, mas também, que os valores impróprios são
  tratados corretamente.

* Esgote o maior número possível de caminhos de código. Teste onde
  ocorre a ramificação e, assim, personalize a entrada para garantir
  que tantos caminhos diferentes pelo código sejam tomados.

* Adicione um teste explícito para quaisquer bugs descobertos ao
  código testado. Isso garantirá que o erro não apareça novamente se o
  código for alterado no futuro.

* Certifique-se de limpar após seus testes (como fechar e remover
  todos os arquivos temporários).

* Se um teste depende de uma condição específica do sistema
  operacional, então verifica se a condição já existe antes de tentar
  o teste.

* Importa o menor número de módulos possível e faça isso o mais rápido
  possível. Isso minimiza dependências externas de testes, e também
  minimiza possíveis comportamento anômalo dos efeitos colaterais da
  importação de um módulo.

* Tente maximizar a reutilização de código. Ocasionalmente, os testes
  variam em algo tão pequeno quanto o tipo de entrada é usado.
  Minimize a duplicação de código criando uma subclasse básica de
  testes com uma classe que especifica o input:

     class TestFuncAcceptsSequencesMixin:

         func = mySuperWhammyFunction

         def test_func(self):
             self.func(self.arg)

     class AcceptLists(TestFuncAcceptsSequencesMixin, unittest.TestCase):
         arg = [1, 2, 3]

     class AcceptStrings(TestFuncAcceptsSequencesMixin, unittest.TestCase):
         arg = 'abc'

     class AcceptTuples(TestFuncAcceptsSequencesMixin, unittest.TestCase):
         arg = (1, 2, 3)

  Ao usar este padrão, lembre-se que todas as classes que herdam de
  "unittest.TestCase" são executadas como testes. A classe "Mixin" no
  exemplo acima não tem nenhum dado e, portanto, não pode ser
  executada sozinha, portanto, ela não herda de "unittest.TestCase".

Ver também:

  Test Driven Development
     Um livro de Kent Beck sobre escrita de testes antes do código.


Executando testes usando a interface de linha de comando
========================================================

O pacote "test" pode ser executado como um script para conduzir o
conjunto de testes de regressão do Python, graças à opção "-m":
**python -m test**. Nos bastidores, ele usa "test.regrtest"; a chamada
**python -m test.regrtest** usado nas versões anteriores do Python
ainda funciona. Executar o script por si só começa a executar todos os
testes de regressão no pacote "test". Ele faz isso encontrando todos
os módulos no pacote cujo nome começa com "test_", importando-os e
executando a função "test_main()" se presente ou carregando os testes
via unittest.TestLoader.loadTestsFromModule se "test_main" não
existir. Os nomes dos testes a serem executados também podem ser
passados para o script. Especificando um teste de regressão simples
(**python -m test test_spam**) minimizará saiba e imprima apenas se o
teste passou ou falhou.

A execução de "test" permite definir diretamente quais recursos estão
disponíveis para os testes usarem. Você faz isso usando a opção de
linha de comando "-u". Especificar "all" como o valor para a opção
"-u" ativa todos os recursos possíveis: **python -m test -uall**. Se
todos menos um recurso for desejado (um caso mais comum), uma lista
separada por vírgulas de recursos que não são desejados pode ser
listada após "all". O comando **python -m test
-uall,-audio,-largefile** executará "test" com todos os recursos,
exceto os recursos "audio" e "largefile". Para obter uma lista de
todos os recursos e mais opções de linha de comando, execute **python
-m test -h**.

Alguns outros meios para executar os testes de regressão dependem em
qual plataforma os testes estão sendo executados. No Unix, você pode
executar: programa: ' make test' no diretório de mais alto nível onde
o Python foi construído. No Windows, executar: programa 'rt.bat' do
seu diretório: file: 'PCbuild' executará todos os testes de regressão.


"test.support" --- Utilitários para o conjunto de teste do Python
*****************************************************************

O módulo "test.support" fornece suporte para a suíte de testes de
regressão do Python.

Nota:

  "test.support" is not a public module.  It is documented here to
  help Python developers write tests.  The API of this module is
  subject to change without backwards compatibility concerns between
  releases.

Esse módulo define as seguintes exceções:

exception test.support.TestFailed

   Exceção a ser levantada quando um teste falha. Isto foi
   descontinuado em favor dos testes baseados em "unittest" e métodos
   de asserção de "unittest.TestCase".

exception test.support.ResourceDenied

   Subclasse de "unittest.SkipTest". Levantada quando um recurso (como
   uma conexão de rede) não está disponível. Levantada pela função
   "requires()".

O módulo "test.support" define as seguintes constantes:

test.support.verbose

   "True" quando a saída detalhada está habilitada. Deve ser
   verificado quando informações mais detalhadas são desejadas sobre
   um teste em execução. *verbose* é definido por "test.regrtest".

test.support.is_jython

   "True" se o interpretador em execução for Jython.

test.support.is_android

   "True" se o sistema é Android.

test.support.unix_shell

   Caminho para o console se não estiver no Windows; por outro lado
   "None"

test.support.FS_NONASCII

   A non-ASCII character encodable by "os.fsencode()".

test.support.TESTFN

   Set to a name that is safe to use as the name of a temporary file.
   Any temporary file that is created should be closed and unlinked
   (removed).

test.support.TESTFN_UNICODE

   Define um nome não-ASCII para o arquivo temporário.

test.support.TESTFN_ENCODING

   Set to "sys.getfilesystemencoding()".

test.support.TESTFN_UNENCODABLE

   Define o nome de arquivo (tipo str) que não pode ser codificado
   pela codificação do sistema de arquivos no modo estrito. Ele pode
   ser "None" se não for possível gerar como um nome de arquivo.

test.support.TESTFN_UNDECODABLE

   Define o nome de arquivo (tipo str) que não pode ser codificado
   pela codificação do sistema de arquivos no modo estrito. Ele pode
   ser "None" se não for possível ser gerado com um nome de arquivo.

test.support.TESTFN_NONASCII

   Set to a filename containing the "FS_NONASCII" character.

test.support.IPV6_ENABLED

   Set to "True" if IPV6 is enabled on this host, "False" otherwise.

test.support.SAVEDCWD

   Set to "os.getcwd()".

test.support.PGO

   Definido quando os testes podem ser ignorados quando não são úteis
   para PGO.

test.support.PIPE_MAX_SIZE

   Uma constante que provavelmente é maior que o tamanho do buffer de
   canal do sistema operacional subjacente, para fazer o bloqueio de
   escritas.

test.support.SOCK_MAX_SIZE

   Uma constante que provavelmente é maior que o tamanho do buffer de
   soquete do sistema operacional subjacente, para fazer o bloqueio de
   escritas.

test.support.TEST_SUPPORT_DIR

   Define o diretório de mais alto nível que contém "test.support".

test.support.TEST_HOME_DIR

   Define o diretório de mais alto nível para o pacote de teste.

test.support.TEST_DATA_DIR

   Set to the "data" directory within the test package.

test.support.MAX_Py_ssize_t

   Define "sys.maxsize" para grandes testes de memória.

test.support.max_memuse

   Set by "set_memlimit()" as the memory limit for big memory tests.
   Limited by "MAX_Py_ssize_t".

test.support.real_max_memuse

   Set by "set_memlimit()" as the memory limit for big memory tests.
   Not limited by "MAX_Py_ssize_t".

test.support.MISSING_C_DOCSTRINGS

   Return "True" if running on CPython, not on Windows, and
   configuration not set with "WITH_DOC_STRINGS".

test.support.HAVE_DOCSTRINGS

   Check for presence of docstrings.

test.support.TEST_HTTP_URL

   Define the URL of a dedicated HTTP server for the network tests.

test.support.ALWAYS_EQ

   Object that is equal to anything.  Used to test mixed type
   comparison.

test.support.LARGEST

   Object that is greater than anything (except itself). Used to test
   mixed type comparison.

test.support.SMALLEST

   Object that is less than anything (except itself). Used to test
   mixed type comparison.

O módulo "test.support" define as seguintes funções:

test.support.forget(module_name)

   Remove the module named *module_name* from "sys.modules" and delete
   any byte-compiled files of the module.

test.support.unload(name)

   Exclui o *name* de "sys.modules".

test.support.unlink(filename)

   Call "os.unlink()" on *filename*.  On Windows platforms, this is
   wrapped with a wait loop that checks for the existence fo the file.

test.support.rmdir(filename)

   Call "os.rmdir()" on *filename*.  On Windows platforms, this is
   wrapped with a wait loop that checks for the existence of the file.

test.support.rmtree(path)

   Call "shutil.rmtree()" on *path* or call "os.lstat()" and
   "os.rmdir()" to remove a path and its contents.  On Windows
   platforms, this is wrapped with a wait loop that checks for the
   existence of the files.

test.support.make_legacy_pyc(source)

   Move a **PEP 3147**/**PEP 488** pyc file to its legacy pyc location
   and return the file system path to the legacy pyc file.  The
   *source* value is the file system path to the source file.  It does
   not need to exist, however the PEP 3147/488 pyc file must exist.

test.support.is_resource_enabled(resource)

   Return "True" if *resource* is enabled and available. The list of
   available resources is only set when "test.regrtest" is executing
   the tests.

test.support.python_is_optimized()

   Return "True" if Python was not built with "-O0" or "-Og".

test.support.with_pymalloc()

   Retorna "_testcapi.WITH_PYMALLOC".

test.support.requires(resource, msg=None)

   Raise "ResourceDenied" if *resource* is not available. *msg* is the
   argument to "ResourceDenied" if it is raised. Always returns "True"
   if called by a function whose "__name__" is "'__main__'". Used when
   tests are executed by "test.regrtest".

test.support.system_must_validate_cert(f)

   Raise "unittest.SkipTest" on TLS certification validation failures.

test.support.sortdict(dict)

   Return a repr of *dict* with keys sorted.

test.support.findfile(filename, subdir=None)

   Return the path to the file named *filename*. If no match is found
   *filename* is returned. This does not equal a failure since it
   could be the path to the file.

   Setting *subdir* indicates a relative path to use to find the file
   rather than looking directly in the path directories.

test.support.create_empty_file(filename)

   Create an empty file with *filename*.  If it already exists,
   truncate it.

test.support.fd_count()

   Conta o número de descritores de arquivos abertos.

test.support.match_test(test)

   Match *test* to patterns set in "set_match_tests()".

test.support.set_match_tests(patterns)

   Define match test with regular expression *patterns*.

test.support.run_unittest(*classes)

   Execute "unittest.TestCase" subclasses passed to the function. The
   function scans the classes for methods starting with the prefix
   "test_" and executes the tests individually.

   It is also legal to pass strings as parameters; these should be
   keys in "sys.modules". Each associated module will be scanned by
   "unittest.TestLoader.loadTestsFromModule()". This is usually seen
   in the following "test_main()" function:

      def test_main():
          support.run_unittest(__name__)

   Isso executará todos os testes definidos no módulo nomeado.

test.support.run_doctest(module, verbosity=None, optionflags=0)

   Run "doctest.testmod()" on the given *module*.  Return
   "(failure_count, test_count)".

   If *verbosity* is "None", "doctest.testmod()" is run with verbosity
   set to "verbose".  Otherwise, it is run with verbosity set to
   "None".  *optionflags* is passed as "optionflags" to
   "doctest.testmod()".

test.support.setswitchinterval(interval)

   Set the "sys.setswitchinterval()" to the given *interval*.  Defines
   a minimum interval for Android systems to prevent the system from
   hanging.

test.support.check_impl_detail(**guards)

   Use this check to guard CPython's implementation-specific tests or
   to run them only on the implementations guarded by the arguments:

      check_impl_detail()               # Only on CPython (default).
      check_impl_detail(jython=True)    # Only on Jython.
      check_impl_detail(cpython=False)  # Everywhere except CPython.

test.support.check_warnings(*filters, quiet=True)

   A convenience wrapper for "warnings.catch_warnings()" that makes it
   easier to test that a warning was correctly raised.  It is
   approximately equivalent to calling
   "warnings.catch_warnings(record=True)" with
   "warnings.simplefilter()" set to "always" and with the option to
   automatically validate the results that are recorded.

   "check_warnings" accepts 2-tuples of the form "("message regexp",
   WarningCategory)" as positional arguments. If one or more *filters*
   are provided, or if the optional keyword argument *quiet* is
   "False", it checks to make sure the warnings are as expected:  each
   specified filter must match at least one of the warnings raised by
   the enclosed code or the test fails, and if any warnings are raised
   that do not match any of the specified filters the test fails.  To
   disable the first of these checks, set *quiet* to "True".

   Se nenhum argumento é especificado, o padrão é:

      check_warnings(("", Warning), quiet=True)

   Nesse caso, todos os avisos são capturados e nenhum erro é gerado.

   On entry to the context manager, a "WarningRecorder" instance is
   returned. The underlying warnings list from "catch_warnings()" is
   available via the recorder object's "warnings" attribute.  As a
   convenience, the attributes of the object representing the most
   recent warning can also be accessed directly through the recorder
   object (see example below).  If no warning has been raised, then
   any of the attributes that would otherwise be expected on an object
   representing a warning will return "None".

   The recorder object also has a "reset()" method, which clears the
   warnings list.

   O gerenciador de contexto é desenhado para ser utilizado dessa
   forma:

      with check_warnings(("assertion is always true", SyntaxWarning),
                          ("", UserWarning)):
          exec('assert(False, "Hey!")')
          warnings.warn(UserWarning("Hide me!"))

   No caso, se um aviso não foi levantado, ou algum outro aviso não
   foi levantado, "check_warnings()" deveria aparecer como um erro.

   When a test needs to look more deeply into the warnings, rather
   than just checking whether or not they occurred, code like this can
   be used:

      with check_warnings(quiet=True) as w:
          warnings.warn("foo")
          assert str(w.args[0]) == "foo"
          warnings.warn("bar")
          assert str(w.args[0]) == "bar"
          assert str(w.warnings[0].args[0]) == "foo"
          assert str(w.warnings[1].args[0]) == "bar"
          w.reset()
          assert len(w.warnings) == 0

   Aqui todos os avisos serão capturados e o código de teste testa os
   avisos diretamente capturados.

   Alterado na versão 3.2: Novos argumentos opcionais *filters* e
   *quiet*.

test.support.check_no_resource_warning(testcase)

   Context manager to check that no "ResourceWarning" was raised.  You
   must remove the object which may emit "ResourceWarning" before the
   end of the context manager.

test.support.set_memlimit(limit)

   Define os valores para "max_memuse" e "real_max_memuse" para
   grandes testes de memória.

test.support.record_original_stdout(stdout)

   Armazena o valor de *stdout*. Destina-se a manter o stdout no
   momento em que o registro começou.

test.support.get_original_stdout()

   Retorna o stdout original definido por "record_original_stdout()"
   ou "sys.stdout" se não estiver definido.

test.support.strip_python_strerr(stderr)

   Strip the *stderr* of a Python process from potential debug output
   emitted by the interpreter.  This will typically be run on the
   result of "subprocess.Popen.communicate()".

test.support.args_from_interpreter_flags()

   Retorna uma lista de argumentos de linha de comando reproduzindo as
   configurações em "sys.flags" e "sys.warnoptions".

test.support.optim_args_from_interpreter_flags()

   Retorna a lista de argumentos da linha de comando reproduzindo as
   configurações de otimização atuais em "sys.flags".

test.support.captured_stdin()
test.support.captured_stdout()
test.support.captured_stderr()

   Um gerenciador de contexto que substitui temporariamente o fluxo
   nomeado pelo objeto "io.StringIO".

   Exemplo do uso com fluxos de saída:

      with captured_stdout() as stdout, captured_stderr() as stderr:
          print("hello")
          print("error", file=sys.stderr)
      assert stdout.getvalue() == "hello\n"
      assert stderr.getvalue() == "error\n"

   Exemplo de uso com fluxo de entrada:

      with captured_stdin() as stdin:
          stdin.write('hello\n')
          stdin.seek(0)
          # call test code that consumes from sys.stdin
          captured = input()
      self.assertEqual(captured, "hello")

test.support.temp_dir(path=None, quiet=False)

   Um gerenciador de contexto que cria um diretório temporário no
   *path* e produz o diretório.

   If *path* is "None", the temporary directory is created using
   "tempfile.mkdtemp()".  If *quiet* is "False", the context manager
   raises an exception on error.  Otherwise, if *path* is specified
   and cannot be created, only a warning is issued.

test.support.change_cwd(path, quiet=False)

   A context manager that temporarily changes the current working
   directory to *path* and yields the directory.

   If *quiet* is "False", the context manager raises an exception on
   error.  Otherwise, it issues only a warning and keeps the current
   working directory the same.

test.support.temp_cwd(name='tempcwd', quiet=False)

   Um gerenciador de contexto que cria temporariamente um novo
   diretório e altera o diretório de trabalho atual (CWD).

   The context manager creates a temporary directory in the current
   directory with name *name* before temporarily changing the current
   working directory.  If *name* is "None", the temporary directory is
   created using "tempfile.mkdtemp()".

   Se *quiet* é "False" e ele não possibilita criar ou alterar o CWD,
   um erro é levantado. Por outro lado, somente um aviso surge e o CWD
   original é utilizado.

test.support.temp_umask(umask)

   Um gerenciador de contexto que temporariamente define o umask do
   processo.

test.support.transient_internet(resource_name, *, timeout=30.0, errnos=())

   A context manager that raises "ResourceDenied" when various issues
   with the internet connection manifest themselves as exceptions.

test.support.disable_faulthandler()

   A context manager that replaces "sys.stderr" with "sys.__stderr__".

test.support.gc_collect()

   Força a coleta de tantos objetos quanto possível. Isso é necessário
   porque a desalocação oportuna não é garantida pelo coletor de lixo.
   Isso significa que os métodos "__del__" podem ser chamados mais
   tarde do que o esperado e as referência fraca podem permanecer
   ativas por mais tempo do que o esperado.

test.support.disable_gc()

   A context manager that disables the garbage collector upon entry
   and reenables it upon exit.

test.support.swap_attr(obj, attr, new_val)

   Context manager to swap out an attribute with a new object.

   Uso:

      with swap_attr(obj, "attr", 5):
          ...

   This will set "obj.attr" to 5 for the duration of the "with" block,
   restoring the old value at the end of the block.  If "attr" doesn't
   exist on "obj", it will be created and then deleted at the end of
   the block.

   The old value (or "None" if it doesn't exist) will be assigned to
   the target of the "as" clause, if there is one.

test.support.swap_item(obj, attr, new_val)

   Context manager to swap out an item with a new object.

   Uso:

      with swap_item(obj, "item", 5):
          ...

   This will set "obj["item"]" to 5 for the duration of the "with"
   block, restoring the old value at the end of the block. If "item"
   doesn't exist on "obj", it will be created and then deleted at the
   end of the block.

   The old value (or "None" if it doesn't exist) will be assigned to
   the target of the "as" clause, if there is one.

test.support.wait_threads_exit(timeout=60.0)

   Context manager to wait until all threads created in the "with"
   statement exit.

test.support.start_threads(threads, unlock=None)

   Context manager to start *threads*.  It attempts to join the
   threads upon exit.

test.support.calcobjsize(fmt)

   Return "struct.calcsize()" for "nP{fmt}0n" or, if
   "gettotalrefcount" exists, "2PnP{fmt}0P".

test.support.calcvobjsize(fmt)

   Return "struct.calcsize()" for "nPn{fmt}0n" or, if
   "gettotalrefcount" exists, "2PnPn{fmt}0P".

test.support.checksizeof(test, o, size)

   For testcase *test*, assert that the "sys.getsizeof" for *o* plus
   the GC header size equals *size*.

test.support.can_symlink()

   Return "True" if the OS supports symbolic links, "False" otherwise.

test.support.can_xattr()

   Return "True" if the OS supports xattr, "False" otherwise.

@test.support.skip_unless_symlink

   Um decorador para executar testes que requerem suporte para links
   simbólicos.

@test.support.skip_unless_xattr

   Um decorador para execução de testes que requerem suporte para
   xattr.

@test.support.skip_unless_bind_unix_socket

   A decorator for running tests that require a functional bind() for
   Unix sockets.

@test.support.anticipate_failure(condition)

   A decorator to conditionally mark tests with
   "unittest.expectedFailure()". Any use of this decorator should have
   an associated comment identifying the relevant tracker issue.

@test.support.run_with_locale(catstr, *locales)

   A decorator for running a function in a different locale, correctly
   resetting it after it has finished.  *catstr* is the locale
   category as a string (for example ""LC_ALL"").  The *locales*
   passed will be tried sequentially, and the first valid locale will
   be used.

@test.support.run_with_tz(tz)

   A decorator for running a function in a specific timezone,
   correctly resetting it after it has finished.

@test.support.requires_freebsd_version(*min_version)

   Decorator for the minimum version when running test on FreeBSD.  If
   the FreeBSD version is less than the minimum, raise
   "unittest.SkipTest".

@test.support.requires_linux_version(*min_version)

   Decorator for the minimum version when running test on Linux.  If
   the Linux version is less than the minimum, raise
   "unittest.SkipTest".

@test.support.requires_mac_version(*min_version)

   Decorator for the minimum version when running test on Mac OS X.
   If the MAC OS X version is less than the minimum, raise
   "unittest.SkipTest".

@test.support.requires_IEEE_754

   Decorator for skipping tests on non-IEEE 754 platforms.

@test.support.requires_zlib

   Decorator for skipping tests if "zlib" doesn't exist.

@test.support.requires_gzip

   Decorator for skipping tests if "gzip" doesn't exist.

@test.support.requires_bz2

   Decorator for skipping tests if "bz2" doesn't exist.

@test.support.requires_lzma

   Decorator for skipping tests if "lzma" doesn't exist.

@test.support.requires_resource(resource)

   Decorator for skipping tests if *resource* is not available.

@test.support.requires_docstrings

   Decorator for only running the test if "HAVE_DOCSTRINGS".

@test.support.cpython_only(test)

   Decorator for tests only applicable to CPython.

@test.support.impl_detail(msg=None, **guards)

   Decorator for invoking "check_impl_detail()" on *guards*.  If that
   returns "False", then uses *msg* as the reason for skipping the
   test.

@test.support.no_tracing(func)

   Decorator to temporarily turn off tracing for the duration of the
   test.

@test.support.refcount_test(test)

   Decorator for tests which involve reference counting.  The
   decorator does not run the test if it is not run by CPython.  Any
   trace function is unset for the duration of the test to prevent
   unexpected refcounts caused by the trace function.

@test.support.reap_threads(func)

   Decorator to ensure the threads are cleaned up even if the test
   fails.

@test.support.bigmemtest(size, memuse, dry_run=True)

   Decorator for bigmem tests.

   *size* is a requested size for the test (in arbitrary, test-
   interpreted units.)  *memuse* is the number of bytes per unit for
   the test, or a good estimate of it.  For example, a test that needs
   two byte buffers, of 4 GiB each, could be decorated with
   "@bigmemtest(size=_4G, memuse=2)".

   The *size* argument is normally passed to the decorated test method
   as an extra argument.  If *dry_run* is "True", the value passed to
   the test method may be less than the requested value.  If *dry_run*
   is "False", it means the test doesn't support dummy runs when "-M"
   is not specified.

@test.support.bigaddrspacetest(f)

   Decorator for tests that fill the address space.  *f* is the
   function to wrap.

test.support.make_bad_fd()

   Cria um descritor de arquivo inválido abrindo e fechando um arquivo
   temporário e retornando seu descritor.

test.support.check_syntax_error(testcase, statement, errtext='', *, lineno=None, offset=None)

   Test for syntax errors in *statement* by attempting to compile
   *statement*. *testcase* is the "unittest" instance for the test.
   *errtext* is the regular expression which should match the string
   representation of the raised "SyntaxError".  If *lineno* is not
   "None", compares to the line of the exception.  If *offset* is not
   "None", compares to the offset of the exception.

test.support.check_syntax_warning(testcase, statement, errtext='', *, lineno=1, offset=None)

   Test for syntax warning in *statement* by attempting to compile
   *statement*. Test also that the "SyntaxWarning" is emitted only
   once, and that it will be converted to a "SyntaxError" when turned
   into error. *testcase* is the "unittest" instance for the test.
   *errtext* is the regular expression which should match the string
   representation of the emitted "SyntaxWarning" and raised
   "SyntaxError".  If *lineno* is not "None", compares to the line of
   the warning and exception. If *offset* is not "None", compares to
   the offset of the exception.

   Novo na versão 3.8.

test.support.open_urlresource(url, *args, **kw)

   Abre *url*. Se falhar em abrir, levanta "TestFailed".

test.support.import_module(name, deprecated=False, *, required_on())

   This function imports and returns the named module. Unlike a normal
   import, this function raises "unittest.SkipTest" if the module
   cannot be imported.

   Module and package deprecation messages are suppressed during this
   import if *deprecated* is "True".  If a module is required on a
   platform but optional for others, set *required_on* to an iterable
   of platform prefixes which will be compared against "sys.platform".

   Novo na versão 3.1.

test.support.import_fresh_module(name, fresh=(), blocked=(), deprecated=False)

   This function imports and returns a fresh copy of the named Python
   module by removing the named module from "sys.modules" before doing
   the import. Note that unlike "reload()", the original module is not
   affected by this operation.

   *fresh* is an iterable of additional module names that are also
   removed from the "sys.modules" cache before doing the import.

   *blocked* is an iterable of module names that are replaced with
   "None" in the module cache during the import to ensure that
   attempts to import them raise "ImportError".

   The named module and any modules named in the *fresh* and *blocked*
   parameters are saved before starting the import and then reinserted
   into "sys.modules" when the fresh import is complete.

   Module and package deprecation messages are suppressed during this
   import if *deprecated* is "True".

   This function will raise "ImportError" if the named module cannot
   be imported.

   Exemplo de uso:

      # Get copies of the warnings module for testing without affecting the
      # version being used by the rest of the test suite. One copy uses the
      # C implementation, the other is forced to use the pure Python fallback
      # implementation
      py_warnings = import_fresh_module('warnings', blocked=['_warnings'])
      c_warnings = import_fresh_module('warnings', fresh=['_warnings'])

   Novo na versão 3.1.

test.support.modules_setup()

   Retorna a cópia de "sys.modules".

test.support.modules_cleanup(oldmodules)

   Remove modules except for *oldmodules* and "encodings" in order to
   preserve internal cache.

test.support.threading_setup()

   Return current thread count and copy of dangling threads.

test.support.threading_cleanup(*original_values)

   Cleanup up threads not specified in *original_values*.  Designed to
   emit a warning if a test leaves running threads in the background.

test.support.join_thread(thread, timeout=30.0)

   Join a *thread* within *timeout*.  Raise an "AssertionError" if
   thread is still alive after *timeout* seconds.

test.support.reap_children()

   Use this at the end of "test_main" whenever sub-processes are
   started. This will help ensure that no extra children (zombies)
   stick around to hog resources and create problems when looking for
   refleaks.

test.support.get_attribute(obj, name)

   Get an attribute, raising "unittest.SkipTest" if "AttributeError"
   is raised.

test.support.bind_port(sock, host=HOST)

   Bind the socket to a free port and return the port number.  Relies
   on ephemeral ports in order to ensure we are using an unbound port.
   This is important as many tests may be running simultaneously,
   especially in a buildbot environment.  This method raises an
   exception if the "sock.family" is "AF_INET" and "sock.type" is
   "SOCK_STREAM", and the socket has "SO_REUSEADDR" or "SO_REUSEPORT"
   set on it. Tests should never set these socket options for TCP/IP
   sockets. The only case for setting these options is testing
   multicasting via multiple UDP sockets.

   Additionally, if the "SO_EXCLUSIVEADDRUSE" socket option is
   available (i.e. on Windows), it will be set on the socket.  This
   will prevent anyone else from binding to our host/port for the
   duration of the test.

test.support.bind_unix_socket(sock, addr)

   Bind a unix socket, raising "unittest.SkipTest" if
   "PermissionError" is raised.

test.support.catch_threading_exception()

   Context manager catching "threading.Thread" exception using
   "threading.excepthook()".

   Attributes set when an exception is catched:

   * "exc_type"

   * "exc_value"

   * "exc_traceback"

   * "thread"

   See "threading.excepthook()" documentation.

   These attributes are deleted at the context manager exit.

   Uso:

      with support.catch_threading_exception() as cm:
          # code spawning a thread which raises an exception
          ...

          # check the thread exception, use cm attributes:
          # exc_type, exc_value, exc_traceback, thread
          ...

      # exc_type, exc_value, exc_traceback, thread attributes of cm no longer
      # exists at this point
      # (to avoid reference cycles)

   Novo na versão 3.8.

test.support.catch_unraisable_exception()

   Context manager catching unraisable exception using
   "sys.unraisablehook()".

   Storing the exception value ("cm.unraisable.exc_value") creates a
   reference cycle. The reference cycle is broken explicitly when the
   context manager exits.

   Storing the object ("cm.unraisable.object") can resurrect it if it
   is set to an object which is being finalized. Exiting the context
   manager clears the stored object.

   Uso:

      with support.catch_unraisable_exception() as cm:
          # code creating an "unraisable exception"
          ...

          # check the unraisable exception: use cm.unraisable
          ...

      # cm.unraisable attribute no longer exists at this point
      # (to break a reference cycle)

   Novo na versão 3.8.

test.support.find_unused_port(family=socket.AF_INET, socktype=socket.SOCK_STREAM)

   Returns an unused port that should be suitable for binding.  This
   is achieved by creating a temporary socket with the same family and
   type as the "sock" parameter (default is "AF_INET", "SOCK_STREAM"),
   and binding it to the specified host address (defaults to
   "0.0.0.0") with the port set to 0, eliciting an unused ephemeral
   port from the OS. The temporary socket is then closed and deleted,
   and the ephemeral port is returned.

   Either this method or "bind_port()" should be used for any tests
   where a server socket needs to be bound to a particular port for
   the duration of the test. Which one to use depends on whether the
   calling code is creating a Python socket, or if an unused port
   needs to be provided in a constructor or passed to an external
   program (i.e. the "-accept" argument to openssl's s_server mode).
   Always prefer "bind_port()" over "find_unused_port()" where
   possible.  Using a hard coded port is discouraged since it can make
   multiple instances of the test impossible to run simultaneously,
   which is a problem for buildbots.

test.support.load_package_tests(pkg_dir, loader, standard_tests, pattern)

   Generic implementation of the "unittest" "load_tests" protocol for
   use in test packages.  *pkg_dir* is the root directory of the
   package; *loader*, *standard_tests*, and *pattern* are the
   arguments expected by "load_tests".  In simple cases, the test
   package's "__init__.py" can be the following:

      import os
      from test.support import load_package_tests

      def load_tests(*args):
          return load_package_tests(os.path.dirname(__file__), *args)

test.support.fs_is_case_insensitive(directory)

   Return "True" if the file system for *directory* is case-
   insensitive.

test.support.detect_api_mismatch(ref_api, other_api, *, ignore=())

   Returns the set of attributes, functions or methods of *ref_api*
   not found on *other_api*, except for a defined list of items to be
   ignored in this check specified in *ignore*.

   By default this skips private attributes beginning with '_' but
   includes all magic methods, i.e. those starting and ending in '__'.

   Novo na versão 3.5.

test.support.patch(test_instance, object_to_patch, attr_name, new_value)

   Override *object_to_patch.attr_name* with *new_value*.  Also add
   cleanup procedure to *test_instance* to restore *object_to_patch*
   for *attr_name*.  The *attr_name* should be a valid attribute for
   *object_to_patch*.

test.support.run_in_subinterp(code)

   Run *code* in subinterpreter.  Raise "unittest.SkipTest" if
   "tracemalloc" is enabled.

test.support.check_free_after_iterating(test, iter, cls, args=())

   Assert that *iter* is deallocated after iterating.

test.support.missing_compiler_executable(cmd_names=[])

   Check for the existence of the compiler executables whose names are
   listed in *cmd_names* or all the compiler executables when
   *cmd_names* is empty and return the first missing executable or
   "None" when none is found missing.

test.support.check__all__(test_case, module, name_of_module=None, extra=(), blacklist=())

   Assert that the "__all__" variable of *module* contains all public
   names.

   The module's public names (its API) are detected automatically
   based on whether they match the public name convention and were
   defined in *module*.

   The *name_of_module* argument can specify (as a string or tuple
   thereof) what module(s) an API could be defined in order to be
   detected as a public API. One case for this is when *module*
   imports part of its public API from other modules, possibly a C
   backend (like "csv" and its "_csv").

   The *extra* argument can be a set of names that wouldn't otherwise
   be automatically detected as "public", like objects without a
   proper "__module__" attribute. If provided, it will be added to the
   automatically detected ones.

   The *blacklist* argument can be a set of names that must not be
   treated as part of the public API even though their names indicate
   otherwise.

   Exemplo de uso:

      import bar
      import foo
      import unittest
      from test import support

      class MiscTestCase(unittest.TestCase):
          def test__all__(self):
              support.check__all__(self, foo)

      class OtherTestCase(unittest.TestCase):
          def test__all__(self):
              extra = {'BAR_CONST', 'FOO_CONST'}
              blacklist = {'baz'}  # Undocumented name.
              # bar imports part of its API from _bar.
              support.check__all__(self, bar, ('bar', '_bar'),
                                   extra=extra, blacklist=blacklist)

   Novo na versão 3.6.

test.support.adjust_int_max_str_digits(max_digits)

   This function returns a context manager that will change the global
   "sys.set_int_max_str_digits()" setting for the duration of the
   context to allow execution of test code that needs a different
   limit on the number of digits when converting between an integer
   and string.

   Novo na versão 3.8.14.

The "test.support" module defines the following classes:

class test.support.TransientResource(exc, **kwargs)

   Instances are a context manager that raises "ResourceDenied" if the
   specified exception type is raised.  Any keyword arguments are
   treated as attribute/value pairs to be compared against any
   exception raised within the "with" statement.  Only if all pairs
   match properly against attributes on the exception is
   "ResourceDenied" raised.

class test.support.EnvironmentVarGuard

   Class used to temporarily set or unset environment variables.
   Instances can be used as a context manager and have a complete
   dictionary interface for querying/modifying the underlying
   "os.environ". After exit from the context manager all changes to
   environment variables done through this instance will be rolled
   back.

   Alterado na versão 3.1: Adicionada uma interface para dicionário.

EnvironmentVarGuard.set(envvar, value)

   Temporariamente define a variável de ambiente "envvar" para o valor
   "value".

EnvironmentVarGuard.unset(envvar)

   Desativa temporariamente a variável de ambiente "envvar".

class test.support.SuppressCrashReport

   A context manager used to try to prevent crash dialog popups on
   tests that are expected to crash a subprocess.

   No Windows, desativa as caixas de diálogo Relatório de Erros do
   Windows usando SetErrorMode <https://msdn.microsoft.com/en-
   us/library/windows/desktop/ms680621.aspx>_.

   On UNIX, "resource.setrlimit()" is used to set
   "resource.RLIMIT_CORE"'s soft limit to 0 to prevent coredump file
   creation.

   On both platforms, the old value is restored by "__exit__()".

class test.support.CleanImport(*module_names)

   A context manager to force import to return a new module reference.
   This is useful for testing module-level behaviors, such as the
   emission of a DeprecationWarning on import.  Example usage:

      with CleanImport('foo'):
          importlib.import_module('foo')  # New reference.

class test.support.DirsOnSysPath(*paths)

   A context manager to temporarily add directories to sys.path.

   This makes a copy of "sys.path", appends any directories given as
   positional arguments, then reverts "sys.path" to the copied
   settings when the context ends.

   Note that *all* "sys.path" modifications in the body of the context
   manager, including replacement of the object, will be reverted at
   the end of the block.

class test.support.SaveSignals

   Class to save and restore signal handlers registered by the Python
   signal handler.

class test.support.Matcher

   matches(self, d, **kwargs)

      Tenta corresponder um único dicionário com os argumentos
      fornecidos.

   match_value(self, k, dv, v)

      Tente combinar um único valor armazenado (*dv*) com um valor
      fornecido (*v*).

class test.support.WarningsRecorder

   Class used to record warnings for unit tests. See documentation of
   "check_warnings()" above for more details.

class test.support.BasicTestRunner

   run(test)

      Executa *test* e retorna o resultado.

class test.support.TestHandler(logging.handlers.BufferingHandler)

   Class for logging support.

class test.support.FakePath(path)

   Simple *path-like object*.  It implements the "__fspath__()" method
   which just returns the *path* argument.  If *path* is an exception,
   it will be raised in "__fspath__()".


"test.support.script_helper" --- Utilities for the Python execution tests
*************************************************************************

The "test.support.script_helper" module provides support for Python's
script execution tests.

test.support.script_helper.interpreter_requires_environment()

   Return "True" if "sys.executable interpreter" requires environment
   variables in order to be able to run at all.

   This is designed to be used with "@unittest.skipIf()" to annotate
   tests that need to use an "assert_python*()" function to launch an
   isolated mode ("-I") or no environment mode ("-E") sub-interpreter
   process.

   A normal build & test does not run into this situation but it can
   happen when trying to run the standard library test suite from an
   interpreter that doesn't have an obvious home with Python's current
   home finding logic.

   Setting "PYTHONHOME" is one way to get most of the testsuite to run
   in that situation.  "PYTHONPATH" or "PYTHONUSERSITE" are other
   common environment variables that might impact whether or not the
   interpreter can start.

test.support.script_helper.run_python_until_end(*args, **env_vars)

   Set up the environment based on *env_vars* for running the
   interpreter in a subprocess.  The values can include "__isolated",
   "__cleanenv", "__cwd", and "TERM".

test.support.script_helper.assert_python_ok(*args, **env_vars)

   Assert that running the interpreter with *args* and optional
   environment variables *env_vars* succeeds ("rc == 0") and return a
   "(return code, stdout, stderr)" tuple.

   If the "__cleanenv" keyword is set, *env_vars* is used as a fresh
   environment.

   Python is started in isolated mode (command line option "-I"),
   except if the "__isolated" keyword is set to "False".

test.support.script_helper.assert_python_failure(*args, **env_vars)

   Assert that running the interpreter with *args* and optional
   environment variables *env_vars* fails ("rc != 0") and return a
   "(return code, stdout, stderr)" tuple.

   See "assert_python_ok()" for more options.

test.support.script_helper.spawn_python(*args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, **kw)

   Run a Python subprocess with the given arguments.

   *kw* is extra keyword args to pass to "subprocess.Popen()". Returns
   a "subprocess.Popen" object.

test.support.script_helper.kill_python(p)

   Run the given "subprocess.Popen" process until completion and
   return stdout.

test.support.script_helper.make_script(script_dir, script_basename, source, omit_suffix=False)

   Cria um script contendo *source* no caminho *script_dir* e
   *script_basename*. Se *omit_suffix* "False", acrescente ".py" ao
   nome. Retorna o caminho completo do script.

test.support.script_helper.make_zip_script(zip_dir, zip_basename, script_name, name_in_zip=None)

   Cria um arquivo zip em *zip_dir* e *zip_basename* com a extensão
   "zip" que contém os arquivos em *script_name*. *name_in_zip* é o
   nome do arquivo. Retorna uma tupla contendo "(full path, full path
   of archive name)".

test.support.script_helper.make_pkg(pkg_dir, init_source='')

   Cria um diretório nomeado *pkg_dir* contendo um arquivo "__init__"
   com *init_source* como seus conteúdos.

test.support.script_helper.make_zip_pkg(zip_dir, zip_basename, pkg_name, script_basename, source, depth=1, compiled=False)

   Create a zip package directory with a path of *zip_dir* and
   *zip_basename* containing an empty "__init__" file and a file
   *script_basename* containing the *source*.  If *compiled* is
   "True", both source files will be compiled and added to the zip
   package.  Return a tuple of the full zip path and the archive name
   for the zip file.
