ops

lib/tornado/test/util.py

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+from __future__ import absolute_import, division, print_function
+
+import contextlib
+import os
+import platform
+import socket
+import sys
+import textwrap
+import warnings
+
+from tornado.testing import bind_unused_port
+
+# Delegate the choice of unittest or unittest2 to tornado.testing.
+from tornado.testing import unittest
+
+skipIfNonUnix = unittest.skipIf(os.name != 'posix' or sys.platform == 'cygwin',
+                                "non-unix platform")
+
+# travis-ci.org runs our tests in an overworked virtual machine, which makes
+# timing-related tests unreliable.
+skipOnTravis = unittest.skipIf('TRAVIS' in os.environ,
+                               'timing tests unreliable on travis')
+
+skipOnAppEngine = unittest.skipIf('APPENGINE_RUNTIME' in os.environ,
+                                  'not available on Google App Engine')
+
+# Set the environment variable NO_NETWORK=1 to disable any tests that
+# depend on an external network.
+skipIfNoNetwork = unittest.skipIf('NO_NETWORK' in os.environ,
+                                  'network access disabled')
+
+skipBefore33 = unittest.skipIf(sys.version_info < (3, 3), 'PEP 380 (yield from) not available')
+skipBefore35 = unittest.skipIf(sys.version_info < (3, 5), 'PEP 492 (async/await) not available')
+skipNotCPython = unittest.skipIf(platform.python_implementation() != 'CPython',
+                                 'Not CPython implementation')
+
+# Used for tests affected by
+# https://bitbucket.org/pypy/pypy/issues/2616/incomplete-error-handling-in
+# TODO: remove this after pypy3 5.8 is obsolete.
+skipPypy3V58 = unittest.skipIf(platform.python_implementation() == 'PyPy' and
+                               sys.version_info > (3,) and
+                               sys.pypy_version_info < (5, 9),
+                               'pypy3 5.8 has buggy ssl module')
+
+
+def _detect_ipv6():
+    if not socket.has_ipv6:
+        # socket.has_ipv6 check reports whether ipv6 was present at compile
+        # time. It's usually true even when ipv6 doesn't work for other reasons.
+        return False
+    sock = None
+    try:
+        sock = socket.socket(socket.AF_INET6)
+        sock.bind(('::1', 0))
+    except socket.error:
+        return False
+    finally:
+        if sock is not None:
+            sock.close()
+    return True
+
+
+skipIfNoIPv6 = unittest.skipIf(not _detect_ipv6(), 'ipv6 support not present')
+
+
+def refusing_port():
+    """Returns a local port number that will refuse all connections.
+
+    Return value is (cleanup_func, port); the cleanup function
+    must be called to free the port to be reused.
+    """
+    # On travis-ci, port numbers are reassigned frequently. To avoid
+    # collisions with other tests, we use an open client-side socket's
+    # ephemeral port number to ensure that nothing can listen on that
+    # port.
+    server_socket, port = bind_unused_port()
+    server_socket.setblocking(1)
+    client_socket = socket.socket()
+    client_socket.connect(("127.0.0.1", port))
+    conn, client_addr = server_socket.accept()
+    conn.close()
+    server_socket.close()
+    return (client_socket.close, client_addr[1])
+
+
+def exec_test(caller_globals, caller_locals, s):
+    """Execute ``s`` in a given context and return the result namespace.
+
+    Used to define functions for tests in particular python
+    versions that would be syntax errors in older versions.
+    """
+    # Flatten the real global and local namespace into our fake
+    # globals: it's all global from the perspective of code defined
+    # in s.
+    global_namespace = dict(caller_globals, **caller_locals)  # type: ignore
+    local_namespace = {}
+    exec(textwrap.dedent(s), global_namespace, local_namespace)
+    return local_namespace
+
+
+def subTest(test, *args, **kwargs):
+    """Compatibility shim for unittest.TestCase.subTest.
+
+    Usage: ``with tornado.test.util.subTest(self, x=x):``
+    """
+    try:
+        subTest = test.subTest  # py34+
+    except AttributeError:
+        subTest = contextlib.contextmanager(lambda *a, **kw: (yield))
+    return subTest(*args, **kwargs)
+
+
+@contextlib.contextmanager
+def ignore_deprecation():
+    """Context manager to ignore deprecation warnings."""
+    with warnings.catch_warnings():
+        warnings.simplefilter('ignore', DeprecationWarning)
+        yield