Index: Lib/test/test_support.py
===================================================================
--- Lib/test/test_support.py	(revision 77953)
+++ Lib/test/test_support.py	(working copy)
@@ -16,6 +16,7 @@
 import unittest
 import importlib
 import UserDict
+import re
 
 __all__ = ["Error", "TestFailed", "ResourceDenied", "import_module",
            "verbose", "use_resources", "max_memuse", "record_original_stdout",
@@ -23,8 +24,8 @@
            "is_resource_enabled", "requires", "find_unused_port", "bind_port",
            "fcmp", "have_unicode", "is_jython", "TESTFN", "HOST", "FUZZ",
            "findfile", "sortdict", "check_syntax_error",
-           "open_urlresource", "check_warnings", "CleanImport",
-           "EnvironmentVarGuard", "captured_output",
+           "open_urlresource", "check_warnings", "check_py3k_warnings",
+           "CleanImport", "EnvironmentVarGuard", "captured_output",
            "captured_stdout", "TransientResource", "transient_internet",
            "run_with_locale", "set_memlimit", "bigmemtest", "bigaddrspacetest",
            "BasicTestRunner", "run_unittest", "run_doctest", "threading_setup",
@@ -466,23 +467,91 @@
        entry to the warnings.catch_warnings() context manager.
     """
     def __init__(self, warnings_list):
-        self.warnings = warnings_list
+        self._warnings = warnings_list
+        self._last = 0
 
     def __getattr__(self, attr):
-        if self.warnings:
-            return getattr(self.warnings[-1], attr)
+        if len(self._warnings) > self._last:
+            return getattr(self._warnings[-1], attr)
         elif attr in warnings.WarningMessage._WARNING_DETAILS:
             return None
         raise AttributeError("%r has no attribute %r" % (self, attr))
 
+    @property
+    def warnings(self):
+        return self._warnings[self._last:]
+
     def reset(self):
-        del self.warnings[:]
+        self._last = len(self._warnings)
 
-@contextlib.contextmanager
-def check_warnings():
+def _filterwarnings(filters, lazy=False):
+    # clear the warning registry of the calling module
+    frame = sys._getframe(2)
+    registry = frame.f_globals.get('__warningregistry__')
+    if registry:
+        registry.clear()
     with warnings.catch_warnings(record=True) as w:
         yield WarningsRecorder(w)
+    # filter the recorded warnings
+    reraise = [warning.message for warning in w]
+    missing = []
+    for msg, cat in filters:
+        seen = False
+        for exc in reraise[:]:
+            message = str(exc)
+            # Filter out the matching messages
+            if (re.match(msg, message, re.I) and
+                issubclass(exc.__class__, cat)):
+                seen = True
+                reraise.remove(exc)
+        if not seen and not lazy:
+            # This filter caught nothing
+            missing.append((msg, cat.__name__))
+    for exc in reraise:
+        raise AssertionError("unhandled warning %r" % exc)
+    for filter in missing:
+        raise AssertionError("filter (%r, %s) did not caught any warning" %
+                             filter)
+
+@contextlib.contextmanager
+def check_warnings(*filters, **kwargs):
+    """Context manager to silence warnings.
+
+    Accept 2-tuples as positional arguments:
+        ("message regexp", WarningCategory)
+
+    Optional argument:
+     - if 'lazy' is True, it does not fail if a filter catch nothing
+        (default False)
+
+    Without argument, it defaults to:
+        check_warnings(("", Warning), lazy=False)
+    """
+    if not filters:
+        filters = (("", Warning),)
+    return _filterwarnings(filters, kwargs.get('lazy'))
+
+@contextlib.contextmanager
+def check_py3k_warnings(*filters, **kwargs):
+    """Context manager to silence py3k warnings.
+
+    Accept 2-tuples as positional arguments:
+        ("message regexp", WarningCategory)
 
+    Optional argument:
+     - if 'lazy' is True, it does not fail if a filter catch nothing
+        (default False)
+
+    Without argument, it defaults to:
+        check_py3k_warnings(("", DeprecationWarning), lazy=False)
+    """
+    if sys.py3kwarning:
+        if not filters:
+            filters = (("", DeprecationWarning),)
+        return _filterwarnings(filters, kwargs.get('lazy'))
+    else:
+        # Dummy generator
+        return ([] for _ in '_')
 
 class CleanImport(object):
     """Context manager to force import to return a new module reference.
@@ -713,7 +782,6 @@
 MAX_Py_ssize_t = sys.maxsize
 
 def set_memlimit(limit):
-    import re
     global max_memuse
     global real_max_memuse
     sizes = {