diff --git a/test-requirements.txt b/test-requirements.txt
index 9a23970..14e4a45 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1 +1,4 @@
+contextlib2
+fixtures
+testtools
 unittest2
diff --git a/traceback2/__init__.py b/traceback2/__init__.py
index e69de29..8ce2a9d 100644
--- a/traceback2/__init__.py
+++ b/traceback2/__init__.py
@@ -0,0 +1,316 @@
+"""Extract, format and print information about Python stack traces."""
+
+import linecache
+import sys
+import operator
+
+__all__ = ['extract_stack', 'extract_tb', 'format_exception',
+           'format_exception_only', 'format_list', 'format_stack',
+           'format_tb', 'print_exc', 'format_exc', 'print_exception',
+           'print_last', 'print_stack', 'print_tb',
+           'clear_frames']
+
+#
+# Formatting and printing lists of traceback lines.
+#
+
+def _format_list_iter(extracted_list):
+    for filename, lineno, name, line in extracted_list:
+        item = '  File "{0}", line {1}, in {2}\n'.format(filename, lineno, name)
+        if line:
+            item = item + '    {0}\n'.format(line.strip())
+        yield item
+
+def print_list(extracted_list, file=None):
+    """Print the list of tuples as returned by extract_tb() or
+    extract_stack() as a formatted stack trace to the given file."""
+    if file is None:
+        file = sys.stderr
+    for item in _format_list_iter(extracted_list):
+        file.write(item)
+
+def format_list(extracted_list):
+    """Format a list of traceback entry tuples for printing.
+
+    Given a list of tuples as returned by extract_tb() or
+    extract_stack(), return a list of strings ready for printing.
+    Each string in the resulting list corresponds to the item with the
+    same index in the argument list.  Each string ends in a newline;
+    the strings may contain internal newlines as well, for those items
+    whose source text line is not None.
+    """
+    return list(_format_list_iter(extracted_list))
+
+#
+# Printing and Extracting Tracebacks.
+#
+
+# extractor takes curr and needs to return a tuple of:
+# - Frame object
+# - Line number
+# - Next item (same type as curr)
+# In practice, curr is either a traceback or a frame.
+def _extract_tb_or_stack_iter(curr, limit, extractor):
+    if limit is None:
+        limit = getattr(sys, 'tracebacklimit', None)
+
+    n = 0
+    while curr is not None and (limit is None or n < limit):
+        f, lineno, next_item = extractor(curr)
+        co = f.f_code
+        filename = co.co_filename
+        name = co.co_name
+
+        linecache.checkcache(filename)
+        line = linecache.getline(filename, lineno, f.f_globals)
+
+        if line:
+            line = line.strip()
+        else:
+            line = None
+
+        yield (filename, lineno, name, line)
+        curr = next_item
+        n += 1
+
+def _extract_tb_iter(tb, limit):
+    return _extract_tb_or_stack_iter(
+                tb, limit,
+                operator.attrgetter("tb_frame", "tb_lineno", "tb_next"))
+
+def print_tb(tb, limit=None, file=None):
+    """Print up to 'limit' stack trace entries from the traceback 'tb'.
+
+    If 'limit' is omitted or None, all entries are printed.  If 'file'
+    is omitted or None, the output goes to sys.stderr; otherwise
+    'file' should be an open file or file-like object with a write()
+    method.
+    """
+    print_list(extract_tb(tb, limit=limit), file=file)
+
+def format_tb(tb, limit=None):
+    """A shorthand for 'format_list(extract_tb(tb, limit))'."""
+    return format_list(extract_tb(tb, limit=limit))
+
+def extract_tb(tb, limit=None):
+    """Return list of up to limit pre-processed entries from traceback.
+
+    This is useful for alternate formatting of stack traces.  If
+    'limit' is omitted or None, all entries are extracted.  A
+    pre-processed stack trace entry is a quadruple (filename, line
+    number, function name, text) representing the information that is
+    usually printed for a stack trace.  The text is a string with
+    leading and trailing whitespace stripped; if the source is not
+    available it is None.
+    """
+    return list(_extract_tb_iter(tb, limit=limit))
+
+#
+# Exception formatting and output.
+#
+
+_cause_message = (
+    "\nThe above exception was the direct cause "
+    "of the following exception:\n")
+
+_context_message = (
+    "\nDuring handling of the above exception, "
+    "another exception occurred:\n")
+
+def _iter_chain(exc, custom_tb=None, seen=None):
+    if seen is None:
+        seen = set()
+    seen.add(exc)
+    its = []
+    context = exc.__context__
+    cause = exc.__cause__
+    if cause is not None and cause not in seen:
+        its.append(_iter_chain(cause, False, seen))
+        its.append([(_cause_message, None)])
+    elif (context is not None and
+          not exc.__suppress_context__ and
+          context not in seen):
+        its.append(_iter_chain(context, None, seen))
+        its.append([(_context_message, None)])
+    its.append([(exc, custom_tb or exc.__traceback__)])
+    # itertools.chain is in an extension module and may be unavailable
+    for it in its:
+        for thing in it:
+            yield thing
+
+def _format_exception_iter(etype, value, tb, limit, chain):
+    if chain:
+        values = _iter_chain(value, tb)
+    else:
+        values = [(value, tb)]
+
+    for value, tb in values:
+        if isinstance(value, str):
+            # This is a cause/context message line
+            yield value + '\n'
+            continue
+        if tb:
+            yield 'Traceback (most recent call last):\n'
+            for it in _format_list_iter(_extract_tb_iter(tb, limit=limit)):
+                yield it
+        for it in _format_exception_only_iter(type(value), value):
+            yield it
+
+def print_exception(etype, value, tb, limit=None, file=None, chain=True):
+    """Print exception up to 'limit' stack trace entries from 'tb' to 'file'.
+
+    This differs from print_tb() in the following ways: (1) if
+    traceback is not None, it prints a header "Traceback (most recent
+    call last):"; (2) it prints the exception type and value after the
+    stack trace; (3) if type is SyntaxError and value has the
+    appropriate format, it prints the line where the syntax error
+    occurred with a caret on the next line indicating the approximate
+    position of the error.
+    """
+    if file is None:
+        file = sys.stderr
+    for line in _format_exception_iter(etype, value, tb, limit, chain):
+        file.write(line)
+
+def format_exception(etype, value, tb, limit=None, chain=True):
+    """Format a stack trace and the exception information.
+
+    The arguments have the same meaning as the corresponding arguments
+    to print_exception().  The return value is a list of strings, each
+    ending in a newline and some containing internal newlines.  When
+    these lines are concatenated and printed, exactly the same text is
+    printed as does print_exception().
+    """
+    return list(_format_exception_iter(etype, value, tb, limit, chain))
+
+def format_exception_only(etype, value):
+    """Format the exception part of a traceback.
+
+    The arguments are the exception type and value such as given by
+    sys.last_type and sys.last_value. The return value is a list of
+    strings, each ending in a newline.
+
+    Normally, the list contains a single string; however, for
+    SyntaxError exceptions, it contains several lines that (when
+    printed) display detailed information about where the syntax
+    error occurred.
+
+    The message indicating which exception occurred is always the last
+    string in the list.
+
+    """
+    return list(_format_exception_only_iter(etype, value))
+
+def _format_exception_only_iter(etype, value):
+    # Gracefully handle (the way Python 2.4 and earlier did) the case of
+    # being called with (None, None).
+    if etype is None:
+        yield _format_final_exc_line(etype, value)
+        return
+
+    stype = getattr(etype, '__qualname__', etype.__name__)
+    smod = etype.__module__
+    if smod not in ("__main__", "builtins"):
+        stype = smod + '.' + stype
+
+    if not issubclass(etype, SyntaxError):
+        yield _format_final_exc_line(stype, value)
+        return
+
+    # It was a syntax error; show exactly where the problem was found.
+    filename = value.filename or "<string>"
+    lineno = str(value.lineno) or '?'
+    yield '  File "{0}", line {1}\n'.format(filename, lineno)
+
+    badline = value.text
+    offset = value.offset
+    if badline is not None:
+        yield '    {0}\n'.format(badline.strip())
+        if offset is not None:
+            caretspace = badline.rstrip('\n')
+            offset = min(len(caretspace), offset) - 1
+            caretspace = caretspace[:offset].lstrip()
+            # non-space whitespace (likes tabs) must be kept for alignment
+            caretspace = ((c.isspace() and c or ' ') for c in caretspace)
+            yield '    {0}^\n'.format(''.join(caretspace))
+    msg = value.msg or "<no detail available>"
+    yield "{0}: {1}\n".format(stype, msg)
+
+def _format_final_exc_line(etype, value):
+    valuestr = _some_str(value)
+    if value is None or not valuestr:
+        line = "%s\n" % etype
+    else:
+        line = "%s: %s\n" % (etype, valuestr)
+    return line
+
+def _some_str(value):
+    try:
+        return str(value)
+    except:
+        return '<unprintable %s object>' % type(value).__name__
+
+def print_exc(limit=None, file=None, chain=True):
+    """Shorthand for 'print_exception(*sys.exc_info(), limit, file)'."""
+    print_exception(*sys.exc_info(), limit=limit, file=file, chain=chain)
+
+def format_exc(limit=None, chain=True):
+    """Like print_exc() but return a string."""
+    return "".join(format_exception(*sys.exc_info(), limit=limit, chain=chain))
+
+def print_last(limit=None, file=None, chain=True):
+    """This is a shorthand for 'print_exception(sys.last_type,
+    sys.last_value, sys.last_traceback, limit, file)'."""
+    if not hasattr(sys, "last_type"):
+        raise ValueError("no last exception")
+    print_exception(sys.last_type, sys.last_value, sys.last_traceback,
+                    limit, file, chain)
+
+#
+# Printing and Extracting Stacks.
+#
+
+def _extract_stack_iter(f, limit=None):
+    return _extract_tb_or_stack_iter(
+                f, limit, lambda f: (f, f.f_lineno, f.f_back))
+
+def _get_stack(f):
+    if f is None:
+        f = sys._getframe().f_back.f_back
+    return f
+
+def print_stack(f=None, limit=None, file=None):
+    """Print a stack trace from its invocation point.
+
+    The optional 'f' argument can be used to specify an alternate
+    stack frame at which to start. The optional 'limit' and 'file'
+    arguments have the same meaning as for print_exception().
+    """
+    print_list(extract_stack(_get_stack(f), limit=limit), file=file)
+
+def format_stack(f=None, limit=None):
+    """Shorthand for 'format_list(extract_stack(f, limit))'."""
+    return format_list(extract_stack(_get_stack(f), limit=limit))
+
+def extract_stack(f=None, limit=None):
+    """Extract the raw traceback from the current stack frame.
+
+    The return value has the same format as for extract_tb().  The
+    optional 'f' and 'limit' arguments have the same meaning as for
+    print_stack().  Each item in the list is a quadruple (filename,
+    line number, function name, text), and the entries are in order
+    from oldest to newest stack frame.
+    """
+    stack = list(_extract_stack_iter(_get_stack(f), limit=limit))
+    stack.reverse()
+    return stack
+
+def clear_frames(tb):
+    "Clear all references to local variables in the frames of a traceback."
+    while tb is not None:
+        try:
+            tb.tb_frame.clear()
+        except RuntimeError:
+            # Ignore the exception raised if the frame is still executing.
+            pass
+        tb = tb.tb_next
diff --git a/traceback2/tests/test_traceback.py b/traceback2/tests/test_traceback.py
new file mode 100644
index 0000000..3598d3f
--- /dev/null
+++ b/traceback2/tests/test_traceback.py
@@ -0,0 +1,461 @@
+"""Test cases for traceback module"""
+
+import doctest
+from io import StringIO
+import sys
+import re
+
+import contextlib2 as contextlib
+import fixtures
+import six
+try:
+    from six import raise_from
+except ImportError:
+# support raise_from on 3.x:
+# submitted to six: https://bitbucket.org/gutworth/six/issue/102/raise-foo-from-bar-is-a-syntax-error-on-27
+    if sys.version_info[:2] > (3, 2):
+        six.exec_("""def raise_from(value, from_value):
+        raise value from from_value
+    """)
+    else:
+        def raise_from(value, from_value):
+            raise value
+import unittest2 as unittest
+import testtools
+from testtools.matchers import DocTestMatches
+
+import traceback2 as traceback
+
+
+@contextlib.contextmanager
+def captured_output(streamname):
+    stream = StringIO()
+    patch = fixtures.MonkeyPatch('sys.%s' % streamname, stream)
+    with patch:
+        yield stream
+
+
+class SyntaxTracebackCases(unittest.TestCase):
+    # For now, a very minimal set of tests.  I want to be sure that
+    # formatting of SyntaxErrors works based on changes for 2.1.
+
+    def get_exception_format(self, func, exc):
+        try:
+            func()
+        except exc as value:
+            return traceback.format_exception_only(exc, value)
+        else:
+            raise ValueError("call did not raise exception")
+
+    def syntax_error_with_caret(self):
+        compile("def fact(x):\n\treturn x!\n", "?", "exec")
+
+    def syntax_error_with_caret_2(self):
+        compile("1 +\n", "?", "exec")
+
+    def syntax_error_bad_indentation(self):
+        compile("def spam():\n  print(1)\n print(2)", "?", "exec")
+
+    def syntax_error_with_caret_non_ascii(self):
+        compile('Python = "\u1e54\xfd\u0163\u0125\xf2\xf1" +', "?", "exec")
+
+    def syntax_error_bad_indentation2(self):
+        compile(" print(2)", "?", "exec")
+
+    def test_caret(self):
+        err = self.get_exception_format(self.syntax_error_with_caret,
+                                        SyntaxError)
+        self.assertEqual(len(err), 4)
+        self.assertTrue(err[1].strip() == "return x!")
+        self.assertIn("^", err[2]) # third line has caret
+        self.assertEqual(err[1].find("!"), err[2].find("^")) # in the right place
+
+        err = self.get_exception_format(self.syntax_error_with_caret_2,
+                                        SyntaxError)
+        self.assertIn("^", err[2]) # third line has caret
+        self.assertEqual(err[2].count('\n'), 1)   # and no additional newline
+        self.assertEqual(err[1].find("+"), err[2].find("^"))  # in the right place
+
+        err = self.get_exception_format(self.syntax_error_with_caret_non_ascii,
+                                        SyntaxError)
+        self.assertIn("^", err[2]) # third line has caret
+        self.assertEqual(err[2].count('\n'), 1)   # and no additional newline
+        self.assertEqual(err[1].find("+"), err[2].find("^"))  # in the right place
+
+    def test_nocaret(self):
+        exc = SyntaxError("error", ("x.py", 23, None, "bad syntax"))
+        err = traceback.format_exception_only(SyntaxError, exc)
+        self.assertEqual(len(err), 3)
+        self.assertEqual(err[1].strip(), "bad syntax")
+
+    def test_bad_indentation(self):
+        err = self.get_exception_format(self.syntax_error_bad_indentation,
+                                        IndentationError)
+        self.assertEqual(len(err), 4)
+        self.assertEqual(err[1].strip(), "print(2)")
+        self.assertIn("^", err[2])
+        self.assertEqual(err[1].find(")"), err[2].find("^"))
+
+        err = self.get_exception_format(self.syntax_error_bad_indentation2,
+                                        IndentationError)
+        self.assertEqual(len(err), 4)
+        self.assertEqual(err[1].strip(), "print(2)")
+        self.assertIn("^", err[2])
+        self.assertEqual(err[1].find("p"), err[2].find("^"))
+
+    def test_base_exception(self):
+        # Test that exceptions derived from BaseException are formatted right
+        e = KeyboardInterrupt()
+        lst = traceback.format_exception_only(e.__class__, e)
+        self.assertEqual(lst, ['KeyboardInterrupt\n'])
+
+    def test_format_exception_only_bad__str__(self):
+        class X(Exception):
+            def __str__(self):
+                1/0
+        err = traceback.format_exception_only(X, X())
+        self.assertEqual(len(err), 1)
+        str_value = '<unprintable %s object>' % X.__name__
+        if X.__module__ in ('__main__', 'builtins'):
+            str_name = X.__qualname__
+        else:
+            str_name = '.'.join([X.__module__, X.__qualname__])
+        self.assertEqual(err[0], "%s: %s\n" % (str_name, str_value))
+
+    def test_without_exception(self):
+        err = traceback.format_exception_only(None, None)
+        self.assertEqual(err, ['None\n'])
+
+    def test_encoded_file(self):
+        # Test that tracebacks are correctly printed for encoded source files:
+        # - correct line number (Issue2384)
+        # - respect file encoding (Issue3975)
+        import tempfile, sys, subprocess, os
+
+        # The spawned subprocess has its stdout redirected to a PIPE, and its
+        # encoding may be different from the current interpreter, on Windows
+        # at least.
+        process = subprocess.Popen([sys.executable, "-c",
+                                    "import sys; print(sys.stdout.encoding)"],
+                                   stdout=subprocess.PIPE,
+                                   stderr=subprocess.STDOUT)
+        stdout, stderr = process.communicate()
+        output_encoding = str(stdout, 'ascii').splitlines()[0]
+
+        def do_test(firstlines, message, charset, lineno):
+            # Raise the message in a subprocess, and catch the output
+            with fixtures.TempDir() as d:
+                TESTFN = d.path + '/fname'
+                output = open(TESTFN, "w", encoding=charset)
+                output.write("""{0}if 1:
+                    import traceback;
+                    raise RuntimeError('{1}')
+                    """.format(firstlines, message))
+                output.close()
+                process = subprocess.Popen([sys.executable, TESTFN],
+                    stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+                stdout, stderr = process.communicate()
+                stdout = stdout.decode(output_encoding).splitlines()
+
+            # The source lines are encoded with the 'backslashreplace' handler
+            encoded_message = message.encode(output_encoding,
+                                             'backslashreplace')
+            # and we just decoded them with the output_encoding.
+            message_ascii = encoded_message.decode(output_encoding)
+
+            err_line = "raise RuntimeError('{0}')".format(message_ascii)
+            err_msg = "RuntimeError: {0}".format(message_ascii)
+
+            self.assertIn(("line %s" % lineno), stdout[1],
+                "Invalid line number: {0!r} instead of {1}".format(
+                    stdout[1], lineno))
+            self.assertTrue(stdout[2].endswith(err_line),
+                "Invalid traceback line: {0!r} instead of {1!r}".format(
+                    stdout[2], err_line))
+            self.assertTrue(stdout[3] == err_msg,
+                "Invalid error message: {0!r} instead of {1!r}".format(
+                    stdout[3], err_msg))
+
+        do_test("", "foo", "ascii", 3)
+        for charset in ("ascii", "iso-8859-1", "utf-8", "GBK"):
+            if charset == "ascii":
+                text = "foo"
+            elif charset == "GBK":
+                text = "\u4E02\u5100"
+            else:
+                text = "h\xe9 ho"
+            do_test("# coding: {0}\n".format(charset),
+                    text, charset, 4)
+            do_test("#!shebang\n# coding: {0}\n".format(charset),
+                    text, charset, 5)
+            do_test(" \t\f\n# coding: {0}\n".format(charset),
+                    text, charset, 5)
+        # Issue #18960: coding spec should has no effect
+        do_test("0\n# coding: GBK\n", "h\xe9 ho", 'utf-8', 5)
+
+
+class TracebackFormatTests(unittest.TestCase):
+
+    def some_exception(self):
+        raise KeyError('blah')
+
+    def check_traceback_format(self, cleanup_func=None):
+        try:
+            from _testcapi import traceback_print
+        except ImportError:
+            traceback_print = None
+        try:
+            self.some_exception()
+        except KeyError:
+            type_, value, tb = sys.exc_info()
+            if cleanup_func is not None:
+                # Clear the inner frames, not this one
+                cleanup_func(tb.tb_next)
+            traceback_fmt = 'Traceback (most recent call last):\n' + \
+                            ''.join(traceback.format_tb(tb))
+            if traceback_print is not None:
+                file_ = StringIO()
+                traceback_print(tb, file_)
+                python_fmt  = file_.getvalue()
+            # Call all _tb and _exc functions
+            with captured_output("stderr") as tbstderr:
+                traceback.print_tb(tb)
+            tbfile = StringIO()
+            traceback.print_tb(tb, file=tbfile)
+            with captured_output("stderr") as excstderr:
+                traceback.print_exc()
+            excfmt = traceback.format_exc()
+            excfile = StringIO()
+            traceback.print_exc(file=excfile)
+        else:
+            self.fail("unable to create test traceback string")
+
+        # Make sure that Python and the traceback module format the same thing
+        if traceback_print is not None:
+            self.assertEqual(traceback_fmt, python_fmt)
+        # Now verify the _tb func output
+        self.assertEqual(tbstderr.getvalue(), tbfile.getvalue())
+        # Now verify the _exc func output
+        self.assertEqual(excstderr.getvalue(), excfile.getvalue())
+        self.assertEqual(excfmt, excfile.getvalue())
+
+        # Make sure that the traceback is properly indented.
+        tb_lines = traceback_fmt.splitlines()
+        self.assertEqual(len(tb_lines), 5)
+        banner = tb_lines[0]
+        location, source_line = tb_lines[-2:]
+        self.assertTrue(banner.startswith('Traceback'))
+        self.assertTrue(location.startswith('  File'))
+        self.assertTrue(source_line.startswith('    raise'))
+
+    def test_traceback_format(self):
+        self.check_traceback_format()
+
+    def test_traceback_format_with_cleared_frames(self):
+        # Check that traceback formatting also works with a clear()ed frame
+        def cleanup_tb(tb):
+            if getattr(tb.tb_frame, 'clear_frames', None):
+                tb.tb_frame.clear()
+        self.check_traceback_format(cleanup_tb)
+
+    def test_stack_format(self):
+        # Verify _stack functions. Note we have to use _getframe(1) to
+        # compare them without this frame appearing in the output
+        with captured_output("stderr") as ststderr:
+            traceback.print_stack(sys._getframe(1))
+        stfile = StringIO()
+        traceback.print_stack(sys._getframe(1), file=stfile)
+        self.assertEqual(ststderr.getvalue(), stfile.getvalue())
+
+        stfmt = traceback.format_stack(sys._getframe(1))
+
+        self.assertEqual(ststderr.getvalue(), "".join(stfmt))
+
+
+cause_message = (
+    "\nThe above exception was the direct cause "
+    "of the following exception:\n\n")
+
+context_message = (
+    "\nDuring handling of the above exception, "
+    "another exception occurred:\n\n")
+
+boundaries = re.compile(
+    '(%s|%s)' % (re.escape(cause_message), re.escape(context_message)))
+
+
+class BaseExceptionReportingTests:
+
+    def get_exception(self, exception_or_callable):
+        if isinstance(exception_or_callable, Exception):
+            return exception_or_callable
+        try:
+            exception_or_callable()
+        except Exception as e:
+            return e
+
+    def zero_div(self):
+        1/0 # In zero_div
+
+    def check_zero_div(self, msg):
+        lines = msg.splitlines()
+        self.assertTrue(lines[-3].startswith('  File'))
+        self.assertIn('1/0 # In zero_div', lines[-2])
+        self.assertTrue(lines[-1].startswith('ZeroDivisionError'), lines[-1])
+
+    def test_simple(self):
+        try:
+            1/0 # Marker
+        except ZeroDivisionError as _:
+            e = _
+        lines = self.get_report(e).splitlines()
+        self.assertEqual(len(lines), 4)
+        self.assertTrue(lines[0].startswith('Traceback'))
+        self.assertTrue(lines[1].startswith('  File'))
+        self.assertIn('1/0 # Marker', lines[2])
+        self.assertTrue(lines[3].startswith('ZeroDivisionError'))
+
+    def test_cause(self):
+        def inner_raise():
+            try:
+                self.zero_div()
+            except ZeroDivisionError as e:
+                raise_from(KeyError, e)
+        def outer_raise():
+            inner_raise() # Marker
+        blocks = boundaries.split(self.get_report(outer_raise))
+        self.assertEqual(len(blocks), 3)
+        self.assertEqual(blocks[1], cause_message)
+        self.check_zero_div(blocks[0])
+        self.assertIn('inner_raise() # Marker', blocks[2])
+
+    def test_context(self):
+        def inner_raise():
+            try:
+                self.zero_div()
+            except ZeroDivisionError:
+                raise KeyError
+        def outer_raise():
+            inner_raise() # Marker
+        blocks = boundaries.split(self.get_report(outer_raise))
+        self.assertEqual(len(blocks), 3)
+        self.assertEqual(blocks[1], context_message)
+        self.check_zero_div(blocks[0])
+        self.assertIn('inner_raise() # Marker', blocks[2])
+
+    def test_context_suppression(self):
+        try:
+            try:
+                raise Exception
+            except:
+                raise_from(ZeroDivisionError, None)
+        except ZeroDivisionError as _:
+            e = _
+        lines = self.get_report(e)
+        self.assertThat(lines, DocTestMatches("""\
+Traceback (most recent call last):
+  File "...traceback2/tests/test_traceback.py", line ..., in test_context_suppression
+    raise_from(ZeroDivisionError, None)
+  File "<string>", line 2, in raise_from
+ZeroDivisionError
+""", doctest.ELLIPSIS))
+
+    def test_cause_and_context(self):
+        # When both a cause and a context are set, only the cause should be
+        # displayed and the context should be muted.
+        def inner_raise():
+            try:
+                self.zero_div()
+            except ZeroDivisionError as _e:
+                e = _e
+            try:
+                xyzzy
+            except NameError:
+                raise_from(KeyError, e)
+        def outer_raise():
+            inner_raise() # Marker
+        blocks = boundaries.split(self.get_report(outer_raise))
+        self.assertEqual(len(blocks), 3)
+        self.assertEqual(blocks[1], cause_message)
+        self.check_zero_div(blocks[0])
+        self.assertIn('inner_raise() # Marker', blocks[2])
+
+    def test_cause_recursive(self):
+        def inner_raise():
+            try:
+                try:
+                    self.zero_div()
+                except ZeroDivisionError as e:
+                    z = e
+                    raise_from(KeyError, e)
+            except KeyError as e:
+                raise_from(z, e)
+        def outer_raise():
+            inner_raise() # Marker
+        blocks = boundaries.split(self.get_report(outer_raise))
+        self.assertEqual(len(blocks), 3)
+        self.assertEqual(blocks[1], cause_message)
+        # The first block is the KeyError raised from the ZeroDivisionError
+        self.assertIn('raise_from(KeyError, e)', blocks[0])
+        self.assertNotIn('1/0', blocks[0])
+        # The second block (apart from the boundary) is the ZeroDivisionError
+        # re-raised from the KeyError
+        self.assertIn('inner_raise() # Marker', blocks[2])
+        self.check_zero_div(blocks[2])
+
+    def test_syntax_error_offset_at_eol(self):
+        # See #10186.
+        def e():
+            raise SyntaxError('', ('', 0, 5, 'hello'))
+        msg = self.get_report(e).splitlines()
+        self.assertEqual(msg[-2], "        ^")
+        def e():
+            exec("x = 5 | 4 |")
+        msg = self.get_report(e).splitlines()
+        self.assertEqual(msg[-2], '              ^')
+
+
+class PyExcReportingTests(BaseExceptionReportingTests, testtools.TestCase):
+    #
+    # This checks reporting through the 'traceback' module, with both
+    # format_exception() and print_exception().
+    #
+
+    def get_report(self, e):
+        e = self.get_exception(e)
+        s = ''.join(
+            traceback.format_exception(type(e), e, e.__traceback__))
+        with captured_output("stderr") as sio:
+            traceback.print_exception(type(e), e, e.__traceback__)
+        self.assertEqual(sio.getvalue(), s)
+        return s
+
+
+class MiscTracebackCases(unittest.TestCase):
+    #
+    # Check non-printing functions in traceback module
+    #
+
+    def test_clear(self):
+        def outer():
+            middle()
+        def middle():
+            inner()
+        def inner():
+            i = 1
+            1/0
+
+        try:
+            outer()
+        except:
+            type_, value, tb = sys.exc_info()
+
+        # Initial assertion: there's one local in the inner frame.
+        inner_frame = tb.tb_next.tb_next.tb_next.tb_frame
+        self.assertEqual(len(inner_frame.f_locals), 1)
+
+        # Clear traceback frames
+        traceback.clear_frames(tb)
+
+        # Local variable dict should now be empty.
+        self.assertEqual(len(inner_frame.f_locals), 0)