### 导航 - [索引](../genindex.xhtml "总目录") - [模块](../py-modindex.xhtml "Python 模块索引") | - [下一页](debug.xhtml "调试和分析") | - [上一页](2to3.xhtml "2to3 - 自动将 Python 2 代码转为 Python 3 代码") | -  - [Python](https://www.python.org/) » - zh\_CN 3.7.3 [文档](../index.xhtml) » - [Python 标准库](index.xhtml) » - [开发工具](development.xhtml) » - $('.inline-search').show(0); | # [`test`](#module-test "test: Regression tests package containing the testing suite for Python.") --- Regression tests package for Python 注解 The [`test`](#module-test "test: Regression tests package containing the testing suite for Python.") package is meant for internal use by Python only. It is documented for the benefit of the core developers of Python. Any use of this package outside of Python's standard library is discouraged as code mentioned here can change or be removed without notice between releases of Python. - - - - - - The [`test`](#module-test "test: Regression tests package containing the testing suite for Python.") package contains all regression tests for Python as well as the modules [`test.support`](#module-test.support "test.support: Support for Python's regression test suite.") and `test.regrtest`. [`test.support`](#module-test.support "test.support: Support for Python's regression test suite.") is used to enhance your tests while `test.regrtest` drives the testing suite. Each module in the [`test`](#module-test "test: Regression tests package containing the testing suite for Python.") package whose name starts with `test_` is a testing suite for a specific module or feature. All new tests should be written using the [`unittest`](unittest.xhtml#module-unittest "unittest: Unit testing framework for Python.") or [`doctest`](doctest.xhtml#module-doctest "doctest: Test pieces of code within docstrings.") module. Some older tests are written using a "traditional" testing style that compares output printed to `sys.stdout`; this style of test is considered deprecated. 参见 Module [`unittest`](unittest.xhtml#module-unittest "unittest: Unit testing framework for Python.")Writing PyUnit regression tests. [`unittest`](unittest.xhtml#module-unittest "unittest: Unit testing framework for Python.") --- 文档测试Tests embedded in documentation strings. ## Writing Unit Tests for the [`test`](#module-test "test: Regression tests package containing the testing suite for Python.") package It is preferred that tests that use the [`unittest`](unittest.xhtml#module-unittest "unittest: Unit testing framework for Python.") module follow a few guidelines. One is to name the test module by starting it with `test_` and end it with the name of the module being tested. The test methods in the test module should start with `test_` and end with a description of what the method is testing. This is needed so that the methods are recognized by the test driver as test methods. Also, no documentation string for the method should be included. A comment (such as `# Tests function returns only True or False`) should be used to provide documentation for test methods. This is done because documentation strings get printed out if they exist and thus what test is being run is not stated. A basic boilerplate is often used: ``` 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() ``` This code pattern allows the testing suite to be run by `test.regrtest`, on its own as a script that supports the [`unittest`](unittest.xhtml#module-unittest "unittest: Unit testing framework for Python.") CLI, or via the `python -m unittest` CLI. The goal for regression testing is to try to break code. This leads to a few guidelines to be followed: - The testing suite should exercise all classes, functions, and constants. This includes not just the external API that is to be presented to the outside world but also "private" code. - Whitebox testing (examining the code being tested when the tests are being written) is preferred. Blackbox testing (testing only the published user interface) is not complete enough to make sure all boundary and edge cases are tested. - Make sure all possible values are tested including invalid ones. This makes sure that not only all valid values are acceptable but also that improper values are handled correctly. - Exhaust as many code paths as possible. Test where branching occurs and thus tailor input to make sure as many different paths through the code are taken. - Add an explicit test for any bugs discovered for the tested code. This will make sure that the error does not crop up again if the code is changed in the future. - Make sure to clean up after your tests (such as close and remove all temporary files). - If a test is dependent on a specific condition of the operating system then verify the condition already exists before attempting the test. - Import as few modules as possible and do it as soon as possible. This minimizes external dependencies of tests and also minimizes possible anomalous behavior from side-effects of importing a module. - Try to maximize code reuse. On occasion, tests will vary by something as small as what type of input is used. Minimize code duplication by subclassing a basic test class with a class that specifies the 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) ``` When using this pattern, remember that all classes that inherit from [`unittest.TestCase`](unittest.xhtml#unittest.TestCase "unittest.TestCase") are run as tests. The `Mixin` class in the example above does not have any data and so can't be run by itself, thus it does not inherit from [`unittest.TestCase`](unittest.xhtml#unittest.TestCase "unittest.TestCase"). 参见 Test Driven DevelopmentA book by Kent Beck on writing tests before code. ## Running tests using the command-line interface The [`test`](#module-test "test: Regression tests package containing the testing suite for Python.") package can be run as a script to drive Python's regression test suite, thanks to the [`-m`](../using/cmdline.xhtml#cmdoption-m) option: **python -m test**. Under the hood, it uses `test.regrtest`; the call **python -m test.regrtest** used in previous Python versions still works. Running the script by itself automatically starts running all regression tests in the [`test`](#module-test "test: Regression tests package containing the testing suite for Python.") package. It does this by finding all modules in the package whose name starts with `test_`, importing them, and executing the function `test_main()` if present or loading the tests via unittest.TestLoader.loadTestsFromModule if `test_main` does not exist. The names of tests to execute may also be passed to the script. Specifying a single regression test (**python -m test test\_spam**) will minimize output and only print whether the test passed or failed. Running [`test`](#module-test "test: Regression tests package containing the testing suite for Python.") directly allows what resources are available for tests to use to be set. You do this by using the `-u` command-line option. Specifying `all` as the value for the `-u` option enables all possible resources: **python -m test -uall**. If all but one resource is desired (a more common case), a comma-separated list of resources that are not desired may be listed after `all`. The command **python -m test -uall,-audio,-largefile**will run [`test`](#module-test "test: Regression tests package containing the testing suite for Python.") with all resources except the `audio` and `largefile` resources. For a list of all resources and more command-line options, run **python -m test -h**. Some other ways to execute the regression tests depend on what platform the tests are being executed on. On Unix, you can run **make test** at the top-level directory where Python was built. On Windows, executing **rt.bat** from your `PCbuild` directory will run all regression tests. # [`test.support`](#module-test.support "test.support: Support for Python's regression test suite.") --- Utilities for the Python test suite The [`test.support`](#module-test.support "test.support: Support for Python's regression test suite.") module provides support for Python's regression test suite. 注解 [`test.support`](#module-test.support "test.support: Support for Python's regression test suite.") 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. This module defines the following exceptions: *exception* `test.support.``TestFailed`Exception to be raised when a test fails. This is deprecated in favor of [`unittest`](unittest.xhtml#module-unittest "unittest: Unit testing framework for Python.")-based tests and [`unittest.TestCase`](unittest.xhtml#unittest.TestCase "unittest.TestCase")'s assertion methods. *exception* `test.support.``ResourceDenied`Subclass of [`unittest.SkipTest`](unittest.xhtml#unittest.SkipTest "unittest.SkipTest"). Raised when a resource (such as a network connection) is not available. Raised by the [`requires()`](#test.support.requires "test.support.requires")function. The [`test.support`](#module-test.support "test.support: Support for Python's regression test suite.") module defines the following constants: `test.support.``verbose``True` when verbose output is enabled. Should be checked when more detailed information is desired about a running test. *verbose* is set by `test.regrtest`. `test.support.``is_jython``True` if the running interpreter is Jython. `test.support.``is_android``True` if the system is Android. `test.support.``unix_shell`Path for shell if not on Windows; otherwise `None`. `test.support.``FS_NONASCII`A non-ASCII character encodable by [`os.fsencode()`](os.xhtml#os.fsencode "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`Set to a non-ASCII name for a temporary file. `test.support.``TESTFN_ENCODING`Set to [`sys.getfilesystemencoding()`](sys.xhtml#sys.getfilesystemencoding "sys.getfilesystemencoding"). `test.support.``TESTFN_UNENCODABLE`Set to a filename (str type) that should not be able to be encoded by file system encoding in strict mode. It may be `None` if it's not possible to generate such a filename. `test.support.``TESTFN_UNDECODABLE`Set to a filename (bytes type) that should not be able to be decoded by file system encoding in strict mode. It may be `None` if it's not possible to generate such a filename. `test.support.``TESTFN_NONASCII`Set to a filename containing the [`FS_NONASCII`](#test.support.FS_NONASCII "test.support.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()`](os.xhtml#os.getcwd "os.getcwd"). `test.support.``PGO`Set when tests can be skipped when they are not useful for PGO. `test.support.``PIPE_MAX_SIZE`A constant that is likely larger than the underlying OS pipe buffer size, to make writes blocking. `test.support.``SOCK_MAX_SIZE`A constant that is likely larger than the underlying OS socket buffer size, to make writes blocking. `test.support.``TEST_SUPPORT_DIR`Set to the top level directory that contains [`test.support`](#module-test.support "test.support: Support for Python's regression test suite."). `test.support.``TEST_HOME_DIR`Set to the top level directory for the test package. `test.support.``TEST_DATA_DIR`Set to the `data` directory within the test package. `test.support.``MAX_Py_ssize_t`Set to [`sys.maxsize`](sys.xhtml#sys.maxsize "sys.maxsize") for big memory tests. `test.support.``max_memuse`Set by [`set_memlimit()`](#test.support.set_memlimit "test.support.set_memlimit") as the memory limit for big memory tests. Limited by [`MAX_Py_ssize_t`](#test.support.MAX_Py_ssize_t "test.support.MAX_Py_ssize_t"). `test.support.``real_max_memuse`Set by [`set_memlimit()`](#test.support.set_memlimit "test.support.set_memlimit") as the memory limit for big memory tests. Not limited by [`MAX_Py_ssize_t`](#test.support.MAX_Py_ssize_t "test.support.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. The [`test.support`](#module-test.support "test.support: Support for Python's regression test suite.") module defines the following functions: `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*)Delete *name* from `sys.modules`. `test.support.``unlink`(*filename*)Call [`os.unlink()`](os.xhtml#os.unlink "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()`](os.xhtml#os.rmdir "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()`](shutil.xhtml#shutil.rmtree "shutil.rmtree") on *path* or call [`os.lstat()`](os.xhtml#os.lstat "os.lstat") and [`os.rmdir()`](os.xhtml#os.rmdir "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 3147/488 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`()Return `_testcapi.WITH_PYMALLOC`. `test.support.``requires`(*resource*, *msg=None*)Raise [`ResourceDenied`](#test.support.ResourceDenied "test.support.ResourceDenied") if *resource* is not available. *msg* is the argument to [`ResourceDenied`](#test.support.ResourceDenied "test.support.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`](unittest.xhtml#unittest.SkipTest "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`()Count the number of open file descriptors. `test.support.``match_test`(*test*)Match *test* to patterns set in [`set_match_tests()`](#test.support.set_match_tests "test.support.set_match_tests"). `test.support.``set_match_tests`(*patterns*)Define match test with regular expression *patterns*. `test.support.``run_unittest`(*\*classes*)Execute [`unittest.TestCase`](unittest.xhtml#unittest.TestCase "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__) ``` This will run all tests defined in the named module. `test.support.``run_doctest`(*module*, *verbosity=None*, *optionflags=0*)Run [`doctest.testmod()`](doctest.xhtml#doctest.testmod "doctest.testmod") on the given *module*. Return `(failure_count, test_count)`. If *verbosity* is `None`, [`doctest.testmod()`](doctest.xhtml#doctest.testmod "doctest.testmod") is run with verbosity set to [`verbose`](#test.support.verbose "test.support.verbose"). Otherwise, it is run with verbosity set to `None`. *optionflags* is passed as `optionflags` to [`doctest.testmod()`](doctest.xhtml#doctest.testmod "doctest.testmod"). `test.support.``setswitchinterval`(*interval*)Set the [`sys.setswitchinterval()`](sys.xhtml#sys.setswitchinterval "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()`](warnings.xhtml#warnings.catch_warnings "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()`](warnings.xhtml#warnings.simplefilter "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`. If no arguments are specified, it defaults to: ``` check_warnings(("", Warning), quiet=True) ``` In this case all warnings are caught and no errors are raised. On entry to the context manager, a `WarningRecorder` instance is returned. The underlying warnings list from [`catch_warnings()`](warnings.xhtml#warnings.catch_warnings "warnings.catch_warnings") is available via the recorder object's [`warnings`](warnings.xhtml#module-warnings "warnings: Issue warning messages and control their disposition.") 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. The context manager is designed to be used like this: ``` with check_warnings(("assertion is always true", SyntaxWarning), ("", UserWarning)): exec('assert(False, "Hey!")') warnings.warn(UserWarning("Hide me!")) ``` In this case if either warning was not raised, or some other warning was raised, [`check_warnings()`](#test.support.check_warnings "test.support.check_warnings") would raise an error. 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 ``` Here all warnings will be caught, and the test code tests the captured warnings directly. 在 3.2 版更改: New optional arguments *filters* and *quiet*. `test.support.``check_no_resource_warning`(*testcase*)Context manager to check that no [`ResourceWarning`](exceptions.xhtml#ResourceWarning "ResourceWarning") was raised. You must remove the object which may emit [`ResourceWarning`](exceptions.xhtml#ResourceWarning "ResourceWarning") before the end of the context manager. `test.support.``set_memlimit`(*limit*)Set the values for [`max_memuse`](#test.support.max_memuse "test.support.max_memuse") and [`real_max_memuse`](#test.support.real_max_memuse "test.support.real_max_memuse") for big memory tests. `test.support.``record_original_stdout`(*stdout*)Store the value from *stdout*. It is meant to hold the stdout at the time the regrtest began. `test.support.``get_original_stdout`()Return the original stdout set by [`record_original_stdout()`](#test.support.record_original_stdout "test.support.record_original_stdout") or `sys.stdout` if it's not set. `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()`](subprocess.xhtml#subprocess.Popen.communicate "subprocess.Popen.communicate"). `test.support.``args_from_interpreter_flags`()Return a list of command line arguments reproducing the current settings in `sys.flags` and `sys.warnoptions`. `test.support.``optim_args_from_interpreter_flags`()Return a list of command line arguments reproducing the current optimization settings in `sys.flags`. `test.support.``captured_stdin`()`test.support.``captured_stdout`()`test.support.``captured_stderr`()A context managers that temporarily replaces the named stream with [`io.StringIO`](io.xhtml#io.StringIO "io.StringIO") object. Example use with output streams: ``` 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" ``` Example use with input stream: ``` 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*)A context manager that creates a temporary directory at *path* and yields the directory. If *path* is `None`, the temporary directory is created using [`tempfile.mkdtemp()`](tempfile.xhtml#tempfile.mkdtemp "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*)A context manager that temporarily creates a new directory and changes the current working directory (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()`](tempfile.xhtml#tempfile.mkdtemp "tempfile.mkdtemp"). If *quiet* is `False` and it is not possible to create or change the CWD, an error is raised. Otherwise, only a warning is raised and the original CWD is used. `test.support.``temp_umask`(*umask*)A context manager that temporarily sets the process umask. `test.support.``transient_internet`(*resource\_name*, *\**, *timeout=30.0*, *errnos=()*)A context manager that raises [`ResourceDenied`](#test.support.ResourceDenied "test.support.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`()Force as many objects as possible to be collected. This is needed because timely deallocation is not guaranteed by the garbage collector. This means that `__del__` methods may be called later than expected and weakrefs may remain alive for longer than expected. `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. 用法: ``` 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. 用法: ``` 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()`](struct.xhtml#struct.calcsize "struct.calcsize") for `nP{fmt}0n` or, if `gettotalrefcount`exists, `2PnP{fmt}0P`. `test.support.``calcvobjsize`(*fmt*)Return [`struct.calcsize()`](struct.xhtml#struct.calcsize "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`A decorator for running tests that require support for symbolic links. `@``test.support.``skip_unless_xattr`A decorator for running tests that require support for 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()`](unittest.xhtml#unittest.expectedFailure "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`](unittest.xhtml#unittest.SkipTest "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`](unittest.xhtml#unittest.SkipTest "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`](unittest.xhtml#unittest.SkipTest "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`](zlib.xhtml#module-zlib "zlib: Low-level interface to compression and decompression routines compatible with gzip.") doesn't exist. `@``test.support.``requires_gzip`Decorator for skipping tests if [`gzip`](gzip.xhtml#module-gzip "gzip: Interfaces for gzip compression and decompression using file objects.") doesn't exist. `@``test.support.``requires_bz2`Decorator for skipping tests if [`bz2`](bz2.xhtml#module-bz2 "bz2: Interfaces for bzip2 compression and decompression.") doesn't exist. `@``test.support.``requires_lzma`Decorator for skipping tests if [`lzma`](lzma.xhtml#module-lzma "lzma: A Python wrapper for the liblzma compression library.") 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.HAVE_DOCSTRINGS "test.support.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()`](#test.support.check_impl_detail "test.support.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`()Create an invalid file descriptor by opening and closing a temporary file, and returning its descriptor. `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`](unittest.xhtml#module-unittest "unittest: Unit testing framework for Python.") instance for the test. *errtext* is the text of the error raised by [`SyntaxError`](exceptions.xhtml#SyntaxError "SyntaxError"). If *lineno* is not None, compares to the line of the [`SyntaxError`](exceptions.xhtml#SyntaxError "SyntaxError"). If *offset* is not None, compares to the offset of the [`SyntaxError`](exceptions.xhtml#SyntaxError "SyntaxError"). `test.support.``open_urlresource`(*url*, *\*args*, *\*\*kw*)Open *url*. If open fails, raises [`TestFailed`](#test.support.TestFailed "test.support.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`](unittest.xhtml#unittest.SkipTest "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`](sys.xhtml#sys.platform "sys.platform"). 3\.1 新版功能. `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`](exceptions.xhtml#ImportError "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`](exceptions.xhtml#ImportError "ImportError") if the named module cannot be imported. Example use: ``` # 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']) ``` 3\.1 新版功能. `test.support.``modules_setup`()Return a copy of [`sys.modules`](sys.xhtml#sys.modules "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`](exceptions.xhtml#AssertionError "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`](unittest.xhtml#unittest.SkipTest "unittest.SkipTest") if [`AttributeError`](exceptions.xhtml#AttributeError "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`](socket.xhtml#socket.AF_INET "socket.AF_INET") and `sock.type` is [`SOCK_STREAM`](socket.xhtml#socket.SOCK_STREAM "socket.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`](unittest.xhtml#unittest.SkipTest "unittest.SkipTest") if [`PermissionError`](exceptions.xhtml#PermissionError "PermissionError") is raised. `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`](socket.xhtml#socket.AF_INET "socket.AF_INET"), [`SOCK_STREAM`](socket.xhtml#socket.SOCK_STREAM "socket.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()`](#test.support.bind_port "test.support.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()`](#test.support.bind_port "test.support.bind_port") over [`find_unused_port()`](#test.support.find_unused_port "test.support.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`](unittest.xhtml#module-unittest "unittest: Unit testing framework for Python.")`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 '\_\_'. 3\.5 新版功能. `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`](unittest.xhtml#unittest.SkipTest "unittest.SkipTest") if [`tracemalloc`](tracemalloc.xhtml#module-tracemalloc "tracemalloc: Trace memory allocations.") 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. Example use: ``` 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) ``` 3\.6 新版功能. The [`test.support`](#module-test.support "test.support: Support for Python's regression test suite.") module defines the following classes: *class* `test.support.``TransientResource`(*exc*, *\*\*kwargs*)Instances are a context manager that raises [`ResourceDenied`](#test.support.ResourceDenied "test.support.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`](../reference/compound_stmts.xhtml#with) statement. Only if all pairs match properly against attributes on the exception is [`ResourceDenied`](#test.support.ResourceDenied "test.support.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. 在 3.1 版更改: Added dictionary interface. `EnvironmentVarGuard.``set`(*envvar*, *value*)Temporarily set the environment variable `envvar` to the value of `value`. `EnvironmentVarGuard.``unset`(*envvar*)Temporarily unset the environment variable `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. On Windows, it disables Windows Error Reporting dialogs using [SetErrorMode](https://msdn.microsoft.com/en-us/library/windows/desktop/ms680621.aspx) \[https://msdn.microsoft.com/en-us/library/windows/desktop/ms680621.aspx\]. On UNIX, [`resource.setrlimit()`](resource.xhtml#resource.setrlimit "resource.setrlimit") is used to set [`resource.RLIMIT_CORE`](resource.xhtml#resource.RLIMIT_CORE "resource.RLIMIT_CORE")'s soft limit to 0 to prevent coredump file creation. On both platforms, the old value is restored by [`__exit__()`](../reference/datamodel.xhtml#object.__exit__ "object.__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`](sys.xhtml#sys.path "sys.path"), appends any directories given as positional arguments, then reverts [`sys.path`](sys.xhtml#sys.path "sys.path") to the copied settings when the context ends. Note that *all* [`sys.path`](sys.xhtml#sys.path "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*)Try to match a single dict with the supplied arguments. `match_value`(*self*, *k*, *dv*, *v*)Try to match a single stored value (*dv*) with a supplied value (*v*). *class* `test.support.``WarningsRecorder`Class used to record warnings for unit tests. See documentation of [`check_warnings()`](#test.support.check_warnings "test.support.check_warnings") above for more details. *class* `test.support.``BasicTestRunner``run`(*test*)Run *test* and return the result. *class* `test.support.``TestHandler`(*logging.handlers.BufferingHandler*)Class for logging support. *class* `test.support.``FakePath`(*path*)Simple [path-like object](../glossary.xhtml#term-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`](#module-test.support.script_helper "test.support.script_helper: Support for Python's script execution tests.") --- Utilities for the Python execution tests The [`test.support.script_helper`](#module-test.support.script_helper "test.support.script_helper: Support for Python's script execution tests.") 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`](../using/cmdline.xhtml#envvar-PYTHONHOME) is one way to get most of the testsuite to run in that situation. [`PYTHONPATH`](../using/cmdline.xhtml#envvar-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()`](#test.support.script_helper.assert_python_ok "test.support.script_helper.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()`](subprocess.xhtml#subprocess.Popen "subprocess.Popen"). Returns a [`subprocess.Popen`](subprocess.xhtml#subprocess.Popen "subprocess.Popen") object. `test.support.script_helper.``kill_python`(*p*)Run the given [`subprocess.Popen`](subprocess.xhtml#subprocess.Popen "subprocess.Popen") process until completion and return stdout. `test.support.script_helper.``make_script`(*script\_dir*, *script\_basename*, *source*, *omit\_suffix=False*)Create script containing *source* in path *script\_dir* and *script\_basename*. If *omit\_suffix* is `False`, append `.py` to the name. Return the full script path. `test.support.script_helper.``make_zip_script`(*zip\_dir*, *zip\_basename*, *script\_name*, *name\_in\_zip=None*)Create zip file at *zip\_dir* and *zip\_basename* with extension `zip` which contains the files in *script\_name*. *name\_in\_zip* is the archive name. Return a tuple containing `(full path, full path of archive name)`. `test.support.script_helper.``make_pkg`(*pkg\_dir*, *init\_source=''*)Create a directory named *pkg\_dir* containing an `__init__` file with *init\_source* as its contents. `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. ### 导航 - [索引](../genindex.xhtml "总目录") - [模块](../py-modindex.xhtml "Python 模块索引") | - [下一页](debug.xhtml "调试和分析") | - [上一页](2to3.xhtml "2to3 - 自动将 Python 2 代码转为 Python 3 代码") | -  - [Python](https://www.python.org/) » - zh\_CN 3.7.3 [文档](../index.xhtml) » - [Python 标准库](index.xhtml) » - [开发工具](development.xhtml) » - $('.inline-search').show(0); | © [版权所有](../copyright.xhtml) 2001-2019, Python Software Foundation. Python 软件基金会是一个非盈利组织。 [请捐助。](https://www.python.org/psf/donations/) 最后更新于 5月 21, 2019. [发现了问题](../bugs.xhtml)？ 使用[Sphinx](http://sphinx.pocoo.org/)1.8.4 创建。