Add future 0.18.2

lib/future/tests/base.py

@@ -0,0 +1,539 @@
+from __future__ import print_function, absolute_import
+import os
+import tempfile
+import unittest
+import sys
+import re
+import warnings
+import io
+from textwrap import dedent
+
+from future.utils import bind_method, PY26, PY3, PY2, PY27
+from future.moves.subprocess import check_output, STDOUT, CalledProcessError
+
+if PY26:
+    import unittest2 as unittest
+
+
+def reformat_code(code):
+    """
+    Removes any leading \n and dedents.
+    """
+    if code.startswith('\n'):
+        code = code[1:]
+    return dedent(code)
+
+
+def order_future_lines(code):
+    """
+    Returns the code block with any ``__future__`` import lines sorted, and
+    then any ``future`` import lines sorted, then any ``builtins`` import lines
+    sorted.
+
+    This only sorts the lines within the expected blocks.
+
+    See test_order_future_lines() for an example.
+    """
+
+    # We need .splitlines(keepends=True), which doesn't exist on Py2,
+    # so we use this instead:
+    lines = code.split('\n')
+
+    uufuture_line_numbers = [i for i, line in enumerate(lines)
+                               if line.startswith('from __future__ import ')]
+
+    future_line_numbers = [i for i, line in enumerate(lines)
+                             if line.startswith('from future')
+                             or line.startswith('from past')]
+
+    builtins_line_numbers = [i for i, line in enumerate(lines)
+                             if line.startswith('from builtins')]
+
+    assert code.lstrip() == code, ('internal usage error: '
+            'dedent the code before calling order_future_lines()')
+
+    def mymax(numbers):
+        return max(numbers) if len(numbers) > 0 else 0
+
+    def mymin(numbers):
+        return min(numbers) if len(numbers) > 0 else float('inf')
+
+    assert mymax(uufuture_line_numbers) <= mymin(future_line_numbers), \
+            'the __future__ and future imports are out of order'
+
+    # assert mymax(future_line_numbers) <= mymin(builtins_line_numbers), \
+    #         'the future and builtins imports are out of order'
+
+    uul = sorted([lines[i] for i in uufuture_line_numbers])
+    sorted_uufuture_lines = dict(zip(uufuture_line_numbers, uul))
+
+    fl = sorted([lines[i] for i in future_line_numbers])
+    sorted_future_lines = dict(zip(future_line_numbers, fl))
+
+    bl = sorted([lines[i] for i in builtins_line_numbers])
+    sorted_builtins_lines = dict(zip(builtins_line_numbers, bl))
+
+    # Replace the old unsorted "from __future__ import ..." lines with the
+    # new sorted ones:
+    new_lines = []
+    for i in range(len(lines)):
+        if i in uufuture_line_numbers:
+            new_lines.append(sorted_uufuture_lines[i])
+        elif i in future_line_numbers:
+            new_lines.append(sorted_future_lines[i])
+        elif i in builtins_line_numbers:
+            new_lines.append(sorted_builtins_lines[i])
+        else:
+            new_lines.append(lines[i])
+    return '\n'.join(new_lines)
+
+
+class VerboseCalledProcessError(CalledProcessError):
+    """
+    Like CalledProcessError, but it displays more information (message and
+    script output) for diagnosing test failures etc.
+    """
+    def __init__(self, msg, returncode, cmd, output=None):
+        self.msg = msg
+        self.returncode = returncode
+        self.cmd = cmd
+        self.output = output
+
+    def __str__(self):
+        return ("Command '%s' failed with exit status %d\nMessage: %s\nOutput: %s"
+                % (self.cmd, self.returncode, self.msg, self.output))
+
+class FuturizeError(VerboseCalledProcessError):
+    pass
+
+class PasteurizeError(VerboseCalledProcessError):
+    pass
+
+
+class CodeHandler(unittest.TestCase):
+    """
+    Handy mixin for test classes for writing / reading / futurizing /
+    running .py files in the test suite.
+    """
+    def setUp(self):
+        """
+        The outputs from the various futurize stages should have the
+        following headers:
+        """
+        # After stage1:
+        # TODO: use this form after implementing a fixer to consolidate
+        #       __future__ imports into a single line:
+        # self.headers1 = """
+        # from __future__ import absolute_import, division, print_function
+        # """
+        self.headers1 = reformat_code("""
+        from __future__ import absolute_import
+        from __future__ import division
+        from __future__ import print_function
+        """)
+
+        # After stage2 --all-imports:
+        # TODO: use this form after implementing a fixer to consolidate
+        #       __future__ imports into a single line:
+        # self.headers2 = """
+        # from __future__ import (absolute_import, division,
+        #                         print_function, unicode_literals)
+        # from future import standard_library
+        # from future.builtins import *
+        # """
+        self.headers2 = reformat_code("""
+        from __future__ import absolute_import
+        from __future__ import division
+        from __future__ import print_function
+        from __future__ import unicode_literals
+        from future import standard_library
+        standard_library.install_aliases()
+        from builtins import *
+        """)
+        self.interpreters = [sys.executable]
+        self.tempdir = tempfile.mkdtemp() + os.path.sep
+        pypath = os.getenv('PYTHONPATH')
+        if pypath:
+            self.env = {'PYTHONPATH': os.getcwd() + os.pathsep + pypath}
+        else:
+            self.env = {'PYTHONPATH': os.getcwd()}
+
+    def convert(self, code, stages=(1, 2), all_imports=False, from3=False,
+                reformat=True, run=True, conservative=False):
+        """
+        Converts the code block using ``futurize`` and returns the
+        resulting code.
+
+        Passing stages=[1] or stages=[2] passes the flag ``--stage1`` or
+        ``stage2`` to ``futurize``. Passing both stages runs ``futurize``
+        with both stages by default.
+
+        If from3 is False, runs ``futurize``, converting from Python 2 to
+        both 2 and 3. If from3 is True, runs ``pasteurize`` to convert
+        from Python 3 to both 2 and 3.
+
+        Optionally reformats the code block first using the reformat() function.
+
+        If run is True, runs the resulting code under all Python
+        interpreters in self.interpreters.
+        """
+        if reformat:
+            code = reformat_code(code)
+        self._write_test_script(code)
+        self._futurize_test_script(stages=stages, all_imports=all_imports,
+                                   from3=from3, conservative=conservative)
+        output = self._read_test_script()
+        if run:
+            for interpreter in self.interpreters:
+                _ = self._run_test_script(interpreter=interpreter)
+        return output
+
+    def compare(self, output, expected, ignore_imports=True):
+        """
+        Compares whether the code blocks are equal. If not, raises an
+        exception so the test fails. Ignores any trailing whitespace like
+        blank lines.
+
+        If ignore_imports is True, passes the code blocks into the
+        strip_future_imports method.
+
+        If one code block is a unicode string and the other a
+        byte-string, it assumes the byte-string is encoded as utf-8.
+        """
+        if ignore_imports:
+            output = self.strip_future_imports(output)
+            expected = self.strip_future_imports(expected)
+        if isinstance(output, bytes) and not isinstance(expected, bytes):
+            output = output.decode('utf-8')
+        if isinstance(expected, bytes) and not isinstance(output, bytes):
+            expected = expected.decode('utf-8')
+        self.assertEqual(order_future_lines(output.rstrip()),
+                         expected.rstrip())
+
+    def strip_future_imports(self, code):
+        """
+        Strips any of these import lines:
+
+            from __future__ import <anything>
+            from future <anything>
+            from future.<anything>
+            from builtins <anything>
+
+        or any line containing:
+            install_hooks()
+        or:
+            install_aliases()
+
+        Limitation: doesn't handle imports split across multiple lines like
+        this:
+
+            from __future__ import (absolute_import, division, print_function,
+                                    unicode_literals)
+        """
+        output = []
+        # We need .splitlines(keepends=True), which doesn't exist on Py2,
+        # so we use this instead:
+        for line in code.split('\n'):
+            if not (line.startswith('from __future__ import ')
+                    or line.startswith('from future ')
+                    or line.startswith('from builtins ')
+                    or 'install_hooks()' in line
+                    or 'install_aliases()' in line
+                    # but don't match "from future_builtins" :)
+                    or line.startswith('from future.')):
+                output.append(line)
+        return '\n'.join(output)
+
+    def convert_check(self, before, expected, stages=(1, 2), all_imports=False,
+                      ignore_imports=True, from3=False, run=True,
+                      conservative=False):
+        """
+        Convenience method that calls convert() and compare().
+
+        Reformats the code blocks automatically using the reformat_code()
+        function.
+
+        If all_imports is passed, we add the appropriate import headers
+        for the stage(s) selected to the ``expected`` code-block, so they
+        needn't appear repeatedly in the test code.
+
+        If ignore_imports is True, ignores the presence of any lines
+        beginning:
+
+            from __future__ import ...
+            from future import ...
+
+        for the purpose of the comparison.
+        """
+        output = self.convert(before, stages=stages, all_imports=all_imports,
+                              from3=from3, run=run, conservative=conservative)
+        if all_imports:
+            headers = self.headers2 if 2 in stages else self.headers1
+        else:
+            headers = ''
+
+        reformatted = reformat_code(expected)
+        if headers in reformatted:
+            headers = ''
+
+        self.compare(output, headers + reformatted,
+                     ignore_imports=ignore_imports)
+
+    def unchanged(self, code, **kwargs):
+        """
+        Convenience method to ensure the code is unchanged by the
+        futurize process.
+        """
+        self.convert_check(code, code, **kwargs)
+
+    def _write_test_script(self, code, filename='mytestscript.py'):
+        """
+        Dedents the given code (a multiline string) and writes it out to
+        a file in a temporary folder like /tmp/tmpUDCn7x/mytestscript.py.
+        """
+        if isinstance(code, bytes):
+            code = code.decode('utf-8')
+        # Be explicit about encoding the temp file as UTF-8 (issue #63):
+        with io.open(self.tempdir + filename, 'wt', encoding='utf-8') as f:
+            f.write(dedent(code))
+
+    def _read_test_script(self, filename='mytestscript.py'):
+        with io.open(self.tempdir + filename, 'rt', encoding='utf-8') as f:
+            newsource = f.read()
+        return newsource
+
+    def _futurize_test_script(self, filename='mytestscript.py', stages=(1, 2),
+                              all_imports=False, from3=False,
+                              conservative=False):
+        params = []
+        stages = list(stages)
+        if all_imports:
+            params.append('--all-imports')
+        if from3:
+            script = 'pasteurize.py'
+        else:
+            script = 'futurize.py'
+            if stages == [1]:
+                params.append('--stage1')
+            elif stages == [2]:
+                params.append('--stage2')
+            else:
+                assert stages == [1, 2]
+            if conservative:
+                params.append('--conservative')
+            # No extra params needed
+
+        # Absolute file path:
+        fn = self.tempdir + filename
+        call_args = [sys.executable, script] + params + ['-w', fn]
+        try:
+            output = check_output(call_args, stderr=STDOUT, env=self.env)
+        except CalledProcessError as e:
+            with open(fn) as f:
+                msg = (
+                    'Error running the command %s\n'
+                    '%s\n'
+                    'Contents of file %s:\n'
+                    '\n'
+                    '%s') % (
+                        ' '.join(call_args),
+                        'env=%s' % self.env,
+                        fn,
+                        '----\n%s\n----' % f.read(),
+                    )
+            ErrorClass = (FuturizeError if 'futurize' in script else PasteurizeError)
+
+            if not hasattr(e, 'output'):
+                # The attribute CalledProcessError.output doesn't exist on Py2.6
+                e.output = None
+            raise ErrorClass(msg, e.returncode, e.cmd, output=e.output)
+        return output
+
+    def _run_test_script(self, filename='mytestscript.py',
+                         interpreter=sys.executable):
+        # Absolute file path:
+        fn = self.tempdir + filename
+        try:
+            output = check_output([interpreter, fn],
+                                  env=self.env, stderr=STDOUT)
+        except CalledProcessError as e:
+            with open(fn) as f:
+                msg = (
+                    'Error running the command %s\n'
+                    '%s\n'
+                    'Contents of file %s:\n'
+                    '\n'
+                    '%s') % (
+                        ' '.join([interpreter, fn]),
+                        'env=%s' % self.env,
+                        fn,
+                        '----\n%s\n----' % f.read(),
+                    )
+            if not hasattr(e, 'output'):
+                # The attribute CalledProcessError.output doesn't exist on Py2.6
+                e.output = None
+            raise VerboseCalledProcessError(msg, e.returncode, e.cmd, output=e.output)
+        return output
+
+
+# Decorator to skip some tests on Python 2.6 ...
+skip26 = unittest.skipIf(PY26, "this test is known to fail on Py2.6")
+
+
+def expectedFailurePY3(func):
+    if not PY3:
+        return func
+    return unittest.expectedFailure(func)
+
+def expectedFailurePY26(func):
+    if not PY26:
+        return func
+    return unittest.expectedFailure(func)
+
+
+def expectedFailurePY27(func):
+    if not PY27:
+        return func
+    return unittest.expectedFailure(func)
+
+
+def expectedFailurePY2(func):
+    if not PY2:
+        return func
+    return unittest.expectedFailure(func)
+
+
+# Renamed in Py3.3:
+if not hasattr(unittest.TestCase, 'assertRaisesRegex'):
+    unittest.TestCase.assertRaisesRegex = unittest.TestCase.assertRaisesRegexp
+
+# From Py3.3:
+def assertRegex(self, text, expected_regex, msg=None):
+    """Fail the test unless the text matches the regular expression."""
+    if isinstance(expected_regex, (str, unicode)):
+        assert expected_regex, "expected_regex must not be empty."
+        expected_regex = re.compile(expected_regex)
+    if not expected_regex.search(text):
+        msg = msg or "Regex didn't match"
+        msg = '%s: %r not found in %r' % (msg, expected_regex.pattern, text)
+        raise self.failureException(msg)
+
+if not hasattr(unittest.TestCase, 'assertRegex'):
+    bind_method(unittest.TestCase, 'assertRegex', assertRegex)
+
+class _AssertRaisesBaseContext(object):
+
+    def __init__(self, expected, test_case, callable_obj=None,
+                 expected_regex=None):
+        self.expected = expected
+        self.test_case = test_case
+        if callable_obj is not None:
+            try:
+                self.obj_name = callable_obj.__name__
+            except AttributeError:
+                self.obj_name = str(callable_obj)
+        else:
+            self.obj_name = None
+        if isinstance(expected_regex, (bytes, str)):
+            expected_regex = re.compile(expected_regex)
+        self.expected_regex = expected_regex
+        self.msg = None
+
+    def _raiseFailure(self, standardMsg):
+        msg = self.test_case._formatMessage(self.msg, standardMsg)
+        raise self.test_case.failureException(msg)
+
+    def handle(self, name, callable_obj, args, kwargs):
+        """
+        If callable_obj is None, assertRaises/Warns is being used as a
+        context manager, so check for a 'msg' kwarg and return self.
+        If callable_obj is not None, call it passing args and kwargs.
+        """
+        if callable_obj is None:
+            self.msg = kwargs.pop('msg', None)
+            return self
+        with self:
+            callable_obj(*args, **kwargs)
+
+class _AssertWarnsContext(_AssertRaisesBaseContext):
+    """A context manager used to implement TestCase.assertWarns* methods."""
+
+    def __enter__(self):
+        # The __warningregistry__'s need to be in a pristine state for tests
+        # to work properly.
+        for v in sys.modules.values():
+            if getattr(v, '__warningregistry__', None):
+                v.__warningregistry__ = {}
+        self.warnings_manager = warnings.catch_warnings(record=True)
+        self.warnings = self.warnings_manager.__enter__()
+        warnings.simplefilter("always", self.expected)
+        return self
+
+    def __exit__(self, exc_type, exc_value, tb):
+        self.warnings_manager.__exit__(exc_type, exc_value, tb)
+        if exc_type is not None:
+            # let unexpected exceptions pass through
+            return
+        try:
+            exc_name = self.expected.__name__
+        except AttributeError:
+            exc_name = str(self.expected)
+        first_matching = None
+        for m in self.warnings:
+            w = m.message
+            if not isinstance(w, self.expected):
+                continue
+            if first_matching is None:
+                first_matching = w
+            if (self.expected_regex is not None and
+                not self.expected_regex.search(str(w))):
+                continue
+            # store warning for later retrieval
+            self.warning = w
+            self.filename = m.filename
+            self.lineno = m.lineno
+            return
+        # Now we simply try to choose a helpful failure message
+        if first_matching is not None:
+            self._raiseFailure('"{}" does not match "{}"'.format(
+                     self.expected_regex.pattern, str(first_matching)))
+        if self.obj_name:
+            self._raiseFailure("{} not triggered by {}".format(exc_name,
+                                                               self.obj_name))
+        else:
+            self._raiseFailure("{} not triggered".format(exc_name))
+
+
+def assertWarns(self, expected_warning, callable_obj=None, *args, **kwargs):
+    """Fail unless a warning of class warnClass is triggered
+       by callable_obj when invoked with arguments args and keyword
+       arguments kwargs.  If a different type of warning is
+       triggered, it will not be handled: depending on the other
+       warning filtering rules in effect, it might be silenced, printed
+       out, or raised as an exception.
+
+       If called with callable_obj omitted or None, will return a
+       context object used like this::
+
+            with self.assertWarns(SomeWarning):
+                do_something()
+
+       An optional keyword argument 'msg' can be provided when assertWarns
+       is used as a context object.
+
+       The context manager keeps a reference to the first matching
+       warning as the 'warning' attribute; similarly, the 'filename'
+       and 'lineno' attributes give you information about the line
+       of Python code from which the warning was triggered.
+       This allows you to inspect the warning after the assertion::
+
+           with self.assertWarns(SomeWarning) as cm:
+               do_something()
+           the_warning = cm.warning
+           self.assertEqual(the_warning.some_attribute, 147)
+    """
+    context = _AssertWarnsContext(expected_warning, self, callable_obj)
+    return context.handle('assertWarns', callable_obj, args, kwargs)
+
+if not hasattr(unittest.TestCase, 'assertWarns'):
+    bind_method(unittest.TestCase, 'assertWarns', assertWarns)