From b3416e44dad82be43d7a2c91b1823514f0076b61 Mon Sep 17 00:00:00 2001
From: Robert Collins <robertc@robertcollins.net>
Date: Fri, 18 Jan 2013 22:17:19 +1300
Subject: [PATCH] * Testtools now depends on extras, a small library split out
 from it to contain   generally useful non-testing facilities. Since extras
 has been around for a   couple of testtools releases now, we're making this
 into a hard dependency of   testtools. (Robert Collins)

* Testtools now uses setuptools rather than distutils so that we can document
  the extras dependency. (Robert Collins)
---
 .bzrignore                              |   1 +
 NEWS                                    |  11 ++
 README                                  |   3 +
 doc/for-test-authors.rst                |   8 +-
 setup.py                                |   8 +-
 testtools/__init__.py                   |   4 +-
 testtools/compat.py                     |   2 +-
 testtools/content.py                    |   3 +-
 testtools/helpers.py                    |  83 +----------
 testtools/testcase.py                   |   3 +-
 testtools/testresult/real.py            |   3 +-
 testtools/tests/helpers.py              |   5 +-
 testtools/tests/test_deferredruntest.py |   3 +-
 testtools/tests/test_distutilscmd.py    |   3 +-
 testtools/tests/test_fixturesupport.py  |   3 +-
 testtools/tests/test_helpers.py         | 183 ------------------------
 testtools/tests/test_run.py             |   3 +-
 testtools/tests/test_spinner.py         |   3 +-
 testtools/tests/test_testresult.py      |   3 +-
 testtools/tests/test_testsuite.py       |   3 +-
 testtools/testsuite.py                  |   8 +-
 21 files changed, 61 insertions(+), 285 deletions(-)

diff --git a/.bzrignore b/.bzrignore
index d6aac0d..c01568f 100644
--- a/.bzrignore
+++ b/.bzrignore
@@ -8,3 +8,4 @@ apidocs
 _trial_temp
 doc/_build
 ./.testrepository
+./testtools.egg-info
diff --git a/NEWS b/NEWS
index 6f3cb8c..42a7f63 100644
--- a/NEWS
+++ b/NEWS
@@ -6,6 +6,17 @@ Changes and improvements to testtools_, grouped by release.
 NEXT
 ~~~~
 
+Changes
+-------
+
+* Testtools now depends on extras, a small library split out from it to contain
+  generally useful non-testing facilities. Since extras has been around for a
+  couple of testtools releases now, we're making this into a hard dependency of
+  testtools. (Robert Collins)
+
+* Testtools now uses setuptools rather than distutils so that we can document
+  the extras dependency. (Robert Collins)
+
 0.9.24
 ~~~~~~
 
diff --git a/README b/README
index dbc685b..cb08d81 100644
--- a/README
+++ b/README
@@ -36,6 +36,9 @@ Required Dependencies
 If you would like to use testtools for earlier Python's, please use testtools
 0.9.15.
 
+ * extras (helpers that we intend to push into Python itself in the near
+   future).
+
 
 Optional Dependencies
 ---------------------
diff --git a/doc/for-test-authors.rst b/doc/for-test-authors.rst
index c9e6c6a..57fd9e2 100644
--- a/doc/for-test-authors.rst
+++ b/doc/for-test-authors.rst
@@ -1288,7 +1288,7 @@ Conditional imports
 -------------------
 
 Lots of the time we would like to conditionally import modules.  testtools
-needs to do this itself, and graciously extends the ability to its users.
+uses the small library extras to do this. This used to be part of testtools.
 
 Instead of::
 
@@ -1317,9 +1317,9 @@ You can do::
 Safe attribute testing
 ----------------------
 
-``hasattr`` is broken_ on many versions of Python.  testtools provides
-``safe_hasattr``, which can be used to safely test whether an object has a
-particular attribute.
+``hasattr`` is broken_ on many versions of Python. The helper ``safe_hasattr``
+can be used to safely test whether an object has a particular attribute. Like
+``try_import`` this used to be in testtools but is now in extras.
 
 
 Nullary callables
diff --git a/setup.py b/setup.py
index 7ecd6d2..fea86b5 100755
--- a/setup.py
+++ b/setup.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 """Distutils installer for testtools."""
 
-from distutils.core import setup
+from setuptools import setup
 import email
 import os
 
@@ -82,4 +82,8 @@ setup(name='testtools',
         'testtools.tests.matchers',
         ],
       cmdclass={'test': testtools.TestCommand},
-      zip_safe=False)
+      zip_safe=False,
+      install_requires=[
+        'extras',
+        ],
+      )
diff --git a/testtools/__init__.py b/testtools/__init__.py
index d722ce5..7b36344 100644
--- a/testtools/__init__.py
+++ b/testtools/__init__.py
@@ -30,10 +30,12 @@ __all__ = [
     'try_imports',
     ]
 
-from testtools.helpers import (
+# Compat - removal announced in 0.9.25.
+from extras import (
     try_import,
     try_imports,
     )
+
 from testtools.matchers._impl import (
     Matcher,
     )
diff --git a/testtools/compat.py b/testtools/compat.py
index 375eca2..bb767ac 100644
--- a/testtools/compat.py
+++ b/testtools/compat.py
@@ -27,7 +27,7 @@ import sys
 import traceback
 import unicodedata
 
-from testtools.helpers import try_imports
+from extras import try_imports
 
 BytesIO = try_imports(['StringIO.StringIO', 'io.BytesIO'])
 StringIO = try_imports(['StringIO.StringIO', 'io.StringIO'])
diff --git a/testtools/content.py b/testtools/content.py
index 8bd4a22..79ff027 100644
--- a/testtools/content.py
+++ b/testtools/content.py
@@ -17,7 +17,8 @@ import os
 import sys
 import traceback
 
-from testtools import try_import
+from extras import try_import
+
 from testtools.compat import _b, _format_exc_info, str_is_unicode, _u
 from testtools.content_type import ContentType, JSON, UTF8_TEXT
 
diff --git a/testtools/helpers.py b/testtools/helpers.py
index 2595c1d..401d2cc 100644
--- a/testtools/helpers.py
+++ b/testtools/helpers.py
@@ -8,83 +8,12 @@ __all__ = [
 
 import sys
 
-
-def try_import(name, alternative=None, error_callback=None):
-    """Attempt to import ``name``.  If it fails, return ``alternative``.
-
-    When supporting multiple versions of Python or optional dependencies, it
-    is useful to be able to try to import a module.
-
-    :param name: The name of the object to import, e.g. ``os.path`` or
-        ``os.path.join``.
-    :param alternative: The value to return if no module can be imported.
-        Defaults to None.
-    :param error_callback: If non-None, a callable that is passed the ImportError
-        when the module cannot be loaded.
-    """
-    module_segments = name.split('.')
-    last_error = None
-    while module_segments:
-        module_name = '.'.join(module_segments)
-        try:
-            module = __import__(module_name)
-        except ImportError:
-            last_error = sys.exc_info()[1]
-            module_segments.pop()
-            continue
-        else:
-            break
-    else:
-        if last_error is not None and error_callback is not None:
-            error_callback(last_error)
-        return alternative
-    nonexistent = object()
-    for segment in name.split('.')[1:]:
-        module = getattr(module, segment, nonexistent)
-        if module is nonexistent:
-            if last_error is not None and error_callback is not None:
-                error_callback(last_error)
-            return alternative
-    return module
-
-
-_RAISE_EXCEPTION = object()
-def try_imports(module_names, alternative=_RAISE_EXCEPTION, error_callback=None):
-    """Attempt to import modules.
-
-    Tries to import the first module in ``module_names``.  If it can be
-    imported, we return it.  If not, we go on to the second module and try
-    that.  The process continues until we run out of modules to try.  If none
-    of the modules can be imported, either raise an exception or return the
-    provided ``alternative`` value.
-
-    :param module_names: A sequence of module names to try to import.
-    :param alternative: The value to return if no module can be imported.
-        If unspecified, we raise an ImportError.
-    :param error_callback: If None, called with the ImportError for *each*
-        module that fails to load.
-    :raises ImportError: If none of the modules can be imported and no
-        alternative value was specified.
-    """
-    module_names = list(module_names)
-    for module_name in module_names:
-        module = try_import(module_name, error_callback=error_callback)
-        if module:
-            return module
-    if alternative is _RAISE_EXCEPTION:
-        raise ImportError(
-            "Could not import any of: %s" % ', '.join(module_names))
-    return alternative
-
-
-def safe_hasattr(obj, attr, _marker=object()):
-    """Does 'obj' have an attribute 'attr'?
-
-    Use this rather than built-in hasattr, as the built-in swallows exceptions
-    in some versions of Python and behaves unpredictably with respect to
-    properties.
-    """
-    return getattr(obj, attr, _marker) is not _marker
+# Compat - removal announced in 0.9.25.
+from extras import (
+    safe_hasattr,
+    try_import,
+    try_imports,
+    )
 
 
 def map_values(function, dictionary):
diff --git a/testtools/testcase.py b/testtools/testcase.py
index fc5f863..cda472e 100644
--- a/testtools/testcase.py
+++ b/testtools/testcase.py
@@ -20,9 +20,10 @@ import sys
 import types
 import unittest
 
+from extras import try_import
+
 from testtools import (
     content,
-    try_import,
     )
 from testtools.compat import (
     advance_iterator,
diff --git a/testtools/testresult/real.py b/testtools/testresult/real.py
index 0a69872..7112ab6 100644
--- a/testtools/testresult/real.py
+++ b/testtools/testresult/real.py
@@ -16,12 +16,13 @@ import datetime
 import sys
 import unittest
 
+from extras import safe_hasattr
+
 from testtools.compat import all, str_is_unicode, _u
 from testtools.content import (
     text_content,
     TracebackContent,
     )
-from testtools.helpers import safe_hasattr
 from testtools.tags import TagContext
 
 # From http://docs.python.org/library/datetime.html
diff --git a/testtools/tests/helpers.py b/testtools/tests/helpers.py
index ade2d96..4024bac 100644
--- a/testtools/tests/helpers.py
+++ b/testtools/tests/helpers.py
@@ -8,10 +8,9 @@ __all__ = [
 
 import sys
 
+from extras import safe_hasattr
+
 from testtools import TestResult
-from testtools.helpers import (
-    safe_hasattr,
-    )
 from testtools.content import TracebackContent
 from testtools import runtest
 
diff --git a/testtools/tests/test_deferredruntest.py b/testtools/tests/test_deferredruntest.py
index 3373c06..aa2d9a6 100644
--- a/testtools/tests/test_deferredruntest.py
+++ b/testtools/tests/test_deferredruntest.py
@@ -5,6 +5,8 @@
 import os
 import signal
 
+from extras import try_import
+
 from testtools import (
     skipIf,
     TestCase,
@@ -13,7 +15,6 @@ from testtools import (
 from testtools.content import (
     text_content,
     )
-from testtools.helpers import try_import
 from testtools.matchers import (
     Equals,
     KeysEqual,
diff --git a/testtools/tests/test_distutilscmd.py b/testtools/tests/test_distutilscmd.py
index 59762df..7bfc1fa 100644
--- a/testtools/tests/test_distutilscmd.py
+++ b/testtools/tests/test_distutilscmd.py
@@ -4,12 +4,13 @@
 
 from distutils.dist import Distribution
 
+from extras import try_import
+
 from testtools.compat import (
     _b,
     _u,
     BytesIO,
     )
-from testtools.helpers import try_import
 fixtures = try_import('fixtures')
 
 import testtools
diff --git a/testtools/tests/test_fixturesupport.py b/testtools/tests/test_fixturesupport.py
index cff9eb4..2ccd1e8 100644
--- a/testtools/tests/test_fixturesupport.py
+++ b/testtools/tests/test_fixturesupport.py
@@ -2,13 +2,14 @@
 
 import unittest
 
+from extras import try_import
+
 from testtools import (
     TestCase,
     content,
     content_type,
     )
 from testtools.compat import _b, _u
-from testtools.helpers import try_import
 from testtools.testresult.doubles import (
     ExtendedTestResult,
     )
diff --git a/testtools/tests/test_helpers.py b/testtools/tests/test_helpers.py
index 98da534..848c2f0 100644
--- a/testtools/tests/test_helpers.py
+++ b/testtools/tests/test_helpers.py
@@ -1,196 +1,13 @@
 # Copyright (c) 2010-2012 testtools developers. See LICENSE for details.
 
 from testtools import TestCase
-from testtools.helpers import (
-    try_import,
-    try_imports,
-    )
-from testtools.matchers import (
-    Equals,
-    Is,
-    Not,
-    )
 from testtools.tests.helpers import (
     FullStackRunTest,
     hide_testtools_stack,
     is_stack_hidden,
-    safe_hasattr,
     )
 
 
-def check_error_callback(test, function, arg, expected_error_count,
-    expect_result):
-    """General test template for error_callback argument.
-
-    :param test: Test case instance.
-    :param function: Either try_import or try_imports.
-    :param arg: Name or names to import.
-    :param expected_error_count: Expected number of calls to the callback.
-    :param expect_result: Boolean for whether a module should
-        ultimately be returned or not.
-    """
-    cb_calls = []
-    def cb(e):
-        test.assertIsInstance(e, ImportError)
-        cb_calls.append(e)
-    try:
-        result = function(arg, error_callback=cb)
-    except ImportError:
-        test.assertFalse(expect_result)
-    else:
-        if expect_result:
-            test.assertThat(result, Not(Is(None)))
-        else:
-            test.assertThat(result, Is(None))
-    test.assertEquals(len(cb_calls), expected_error_count)
-
-
-class TestSafeHasattr(TestCase):
-
-    def test_attribute_not_there(self):
-        class Foo(object):
-            pass
-        self.assertEqual(False, safe_hasattr(Foo(), 'anything'))
-
-    def test_attribute_there(self):
-        class Foo(object):
-            pass
-        foo = Foo()
-        foo.attribute = None
-        self.assertEqual(True, safe_hasattr(foo, 'attribute'))
-
-    def test_property_there(self):
-        class Foo(object):
-            @property
-            def attribute(self):
-                return None
-        foo = Foo()
-        self.assertEqual(True, safe_hasattr(foo, 'attribute'))
-
-    def test_property_raises(self):
-        class Foo(object):
-            @property
-            def attribute(self):
-                1/0
-        foo = Foo()
-        self.assertRaises(ZeroDivisionError, safe_hasattr, foo, 'attribute')
-
-
-class TestTryImport(TestCase):
-
-    def test_doesnt_exist(self):
-        # try_import('thing', foo) returns foo if 'thing' doesn't exist.
-        marker = object()
-        result = try_import('doesntexist', marker)
-        self.assertThat(result, Is(marker))
-
-    def test_None_is_default_alternative(self):
-        # try_import('thing') returns None if 'thing' doesn't exist.
-        result = try_import('doesntexist')
-        self.assertThat(result, Is(None))
-
-    def test_existing_module(self):
-        # try_import('thing', foo) imports 'thing' and returns it if it's a
-        # module that exists.
-        result = try_import('os', object())
-        import os
-        self.assertThat(result, Is(os))
-
-    def test_existing_submodule(self):
-        # try_import('thing.another', foo) imports 'thing' and returns it if
-        # it's a module that exists.
-        result = try_import('os.path', object())
-        import os
-        self.assertThat(result, Is(os.path))
-
-    def test_nonexistent_submodule(self):
-        # try_import('thing.another', foo) imports 'thing' and returns foo if
-        # 'another' doesn't exist.
-        marker = object()
-        result = try_import('os.doesntexist', marker)
-        self.assertThat(result, Is(marker))
-
-    def test_object_from_module(self):
-        # try_import('thing.object') imports 'thing' and returns
-        # 'thing.object' if 'thing' is a module and 'object' is not.
-        result = try_import('os.path.join')
-        import os
-        self.assertThat(result, Is(os.path.join))
-
-    def test_error_callback(self):
-        # the error callback is called on failures.
-        check_error_callback(self, try_import, 'doesntexist', 1, False)
-
-    def test_error_callback_missing_module_member(self):
-        # the error callback is called on failures to find an object
-        # inside an existing module.
-        check_error_callback(self, try_import, 'os.nonexistent', 1, False)
-
-    def test_error_callback_not_on_success(self):
-        # the error callback is not called on success.
-        check_error_callback(self, try_import, 'os.path', 0, True)
-
-
-class TestTryImports(TestCase):
-
-    def test_doesnt_exist(self):
-        # try_imports('thing', foo) returns foo if 'thing' doesn't exist.
-        marker = object()
-        result = try_imports(['doesntexist'], marker)
-        self.assertThat(result, Is(marker))
-
-    def test_fallback(self):
-        result = try_imports(['doesntexist', 'os'])
-        import os
-        self.assertThat(result, Is(os))
-
-    def test_None_is_default_alternative(self):
-        # try_imports('thing') returns None if 'thing' doesn't exist.
-        e = self.assertRaises(
-            ImportError, try_imports, ['doesntexist', 'noreally'])
-        self.assertThat(
-            str(e),
-            Equals("Could not import any of: doesntexist, noreally"))
-
-    def test_existing_module(self):
-        # try_imports('thing', foo) imports 'thing' and returns it if it's a
-        # module that exists.
-        result = try_imports(['os'], object())
-        import os
-        self.assertThat(result, Is(os))
-
-    def test_existing_submodule(self):
-        # try_imports('thing.another', foo) imports 'thing' and returns it if
-        # it's a module that exists.
-        result = try_imports(['os.path'], object())
-        import os
-        self.assertThat(result, Is(os.path))
-
-    def test_nonexistent_submodule(self):
-        # try_imports('thing.another', foo) imports 'thing' and returns foo if
-        # 'another' doesn't exist.
-        marker = object()
-        result = try_imports(['os.doesntexist'], marker)
-        self.assertThat(result, Is(marker))
-
-    def test_fallback_submodule(self):
-        result = try_imports(['os.doesntexist', 'os.path'])
-        import os
-        self.assertThat(result, Is(os.path))
-
-    def test_error_callback(self):
-        # One error for every class that doesn't exist.
-        check_error_callback(self, try_imports,
-            ['os.doesntexist', 'os.notthiseither'],
-            2, False)
-        check_error_callback(self, try_imports,
-            ['os.doesntexist', 'os.notthiseither', 'os'],
-            2, True)
-        check_error_callback(self, try_imports,
-            ['os.path'],
-            0, True)
-
-
 class TestStackHiding(TestCase):
 
     run_tests_with = FullStackRunTest
diff --git a/testtools/tests/test_run.py b/testtools/tests/test_run.py
index 5971a4b..f53d59f 100644
--- a/testtools/tests/test_run.py
+++ b/testtools/tests/test_run.py
@@ -4,11 +4,12 @@
 
 from unittest import TestSuite
 
+from extras import try_import
+
 from testtools.compat import (
     _b,
     StringIO,
     )
-from testtools.helpers import try_import
 fixtures = try_import('fixtures')
 
 import testtools
diff --git a/testtools/tests/test_spinner.py b/testtools/tests/test_spinner.py
index 3d677bd..3ba3ce8 100644
--- a/testtools/tests/test_spinner.py
+++ b/testtools/tests/test_spinner.py
@@ -5,11 +5,12 @@
 import os
 import signal
 
+from extras import try_import
+
 from testtools import (
     skipIf,
     TestCase,
     )
-from testtools.helpers import try_import
 from testtools.matchers import (
     Equals,
     Is,
diff --git a/testtools/tests/test_testresult.py b/testtools/tests/test_testresult.py
index c935b14..64bb743 100644
--- a/testtools/tests/test_testresult.py
+++ b/testtools/tests/test_testresult.py
@@ -15,6 +15,8 @@ import threading
 from unittest import TestSuite
 import warnings
 
+from extras import safe_hasattr
+
 from testtools import (
     ExtendedToOriginalDecorator,
     MultiTestResult,
@@ -44,7 +46,6 @@ from testtools.content import (
     TracebackContent,
     )
 from testtools.content_type import ContentType, UTF8_TEXT
-from testtools.helpers import safe_hasattr
 from testtools.matchers import (
     Contains,
     DocTestMatches,
diff --git a/testtools/tests/test_testsuite.py b/testtools/tests/test_testsuite.py
index 3fc837c..d220709 100644
--- a/testtools/tests/test_testsuite.py
+++ b/testtools/tests/test_testsuite.py
@@ -6,13 +6,14 @@ __metaclass__ = type
 
 import unittest
 
+from extras import try_import
+
 from testtools import (
     ConcurrentTestSuite,
     iterate_tests,
     PlaceHolder,
     TestCase,
     )
-from testtools.helpers import try_import
 from testtools.testsuite import FixtureSuite, iterate_tests, sorted_tests
 from testtools.tests.helpers import LoggingResult
 
diff --git a/testtools/testsuite.py b/testtools/testsuite.py
index 67ace56..668831c 100644
--- a/testtools/testsuite.py
+++ b/testtools/testsuite.py
@@ -9,13 +9,13 @@ __all__ = [
   'sorted_tests',
   ]
 
-from testtools.helpers import safe_hasattr, try_imports
-
-Queue = try_imports(['Queue.Queue', 'queue.Queue'])
-
 import threading
 import unittest
 
+from extras import safe_hasattr, try_imports
+
+Queue = try_imports(['Queue.Queue', 'queue.Queue'])
+
 import testtools