~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2006-2011 Canonical Ltd

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""Test the lazy_import functionality."""

import os

import sys

from bzrlib import (

    errors,

    lazy_import,

    osutils,

    )

from bzrlib.tests import (

    TestCase,

    TestCaseInTempDir,

    )

class InstrumentedReplacer(lazy_import.ScopeReplacer):

    """Track what actions are done"""

    @staticmethod

    def use_actions(actions):

        InstrumentedReplacer.actions = actions

    def _replace(self):

        InstrumentedReplacer.actions.append('_replace')

        return lazy_import.ScopeReplacer._replace(self)

    def __getattribute__(self, attr):

        InstrumentedReplacer.actions.append(('__getattribute__', attr))

        return lazy_import.ScopeReplacer.__getattribute__(self, attr)

    def __call__(self, *args, **kwargs):

        InstrumentedReplacer.actions.append(('__call__', args, kwargs))

        return lazy_import.ScopeReplacer.__call__(self, *args, **kwargs)

class InstrumentedImportReplacer(lazy_import.ImportReplacer):

    @staticmethod

    def use_actions(actions):

        InstrumentedImportReplacer.actions = actions

    def _import(self, scope, name):

        InstrumentedImportReplacer.actions.append(('_import', name))

        return lazy_import.ImportReplacer._import(self, scope, name)

    def _replace(self):

        InstrumentedImportReplacer.actions.append('_replace')

        return lazy_import.ScopeReplacer._replace(self)

    def __getattribute__(self, attr):

        InstrumentedImportReplacer.actions.append(('__getattribute__', attr))

        return lazy_import.ScopeReplacer.__getattribute__(self, attr)

    def __call__(self, *args, **kwargs):

        InstrumentedImportReplacer.actions.append(('__call__', args, kwargs))

        return lazy_import.ScopeReplacer.__call__(self, *args, **kwargs)

class TestClass(object):

    """Just a simple test class instrumented for the test cases"""

    class_member = 'class_member'

    @staticmethod

    def use_actions(actions):

        TestClass.actions = actions

    def __init__(self):

        TestClass.actions.append('init')

    def foo(self, x):

        TestClass.actions.append(('foo', x))

        return 'foo'

class TestScopeReplacer(TestCase):

    """Test the ability of the replacer to put itself into the correct scope.

    In these tests we use the global scope, because we cannot replace

    variables in the local scope. This means that we need to be careful

    and not have the replacing objects use the same name, or we would

    get collisions.

    """

    def setUp(self):

        TestCase.setUp(self)

        # These tests assume we will not be proxying, so make sure proxying is

        # disabled.

        orig_proxy = lazy_import.ScopeReplacer._should_proxy

        def restore():

            lazy_import.ScopeReplacer._should_proxy = orig_proxy

        lazy_import.ScopeReplacer._should_proxy = False

    def test_object(self):

        """ScopeReplacer can create an instance in local scope.

        An object should appear in globals() by constructing a ScopeReplacer,

        and it will be replaced with the real object upon the first request.

        """

        actions = []

        InstrumentedReplacer.use_actions(actions)

        TestClass.use_actions(actions)

        def factory(replacer, scope, name):

            actions.append('factory')

            return TestClass()

        try:

            test_obj1

        except NameError:

            # test_obj1 shouldn't exist yet

            pass

        else:

            self.fail('test_obj1 was not supposed to exist yet')

        InstrumentedReplacer(scope=globals(), name='test_obj1',

                             factory=factory)

        # We can't use isinstance() because that uses test_obj1.__class__

        # and that goes through __getattribute__ which would activate

        # the replacement

        self.assertEqual(InstrumentedReplacer,

                         object.__getattribute__(test_obj1, '__class__'))

        self.assertEqual('foo', test_obj1.foo(1))

        self.assertIsInstance(test_obj1, TestClass)

        self.assertEqual('foo', test_obj1.foo(2))

        self.assertEqual([('__getattribute__', 'foo'),

                          '_replace',

                          'factory',

                          'init',

                          ('foo', 1),

                          ('foo', 2),

                         ], actions)

    def test_setattr_replaces(self):

        """ScopeReplacer can create an instance in local scope.

        An object should appear in globals() by constructing a ScopeReplacer,

        and it will be replaced with the real object upon the first request.

        """

        actions = []

        TestClass.use_actions(actions)

        def factory(replacer, scope, name):

            return TestClass()

        try:

            test_obj6

        except NameError:

            # test_obj6 shouldn't exist yet

            pass

        else:

            self.fail('test_obj6 was not supposed to exist yet')

        lazy_import.ScopeReplacer(scope=globals(), name='test_obj6',

                                  factory=factory)

        # We can't use isinstance() because that uses test_obj6.__class__

        # and that goes through __getattribute__ which would activate

        # the replacement

        self.assertEqual(lazy_import.ScopeReplacer,

                         object.__getattribute__(test_obj6, '__class__'))

        test_obj6.bar = 'test'

        self.assertNotEqual(lazy_import.ScopeReplacer,

                            object.__getattribute__(test_obj6, '__class__'))

        self.assertEqual('test', test_obj6.bar)

    def test_replace_side_effects(self):

        """Creating a new object should only create one entry in globals.

        And only that entry even after replacement.

        """

        try:

            test_scope1

        except NameError:

            # test_scope1 shouldn't exist yet

            pass

        else:

            self.fail('test_scope1 was not supposed to exist yet')

        # ignore the logged actions

        TestClass.use_actions([])

        def factory(replacer, scope, name):

            return TestClass()

        orig_globals = set(globals().keys())

        lazy_import.ScopeReplacer(scope=globals(), name='test_scope1',

                                  factory=factory)

        new_globals = set(globals().keys())

        self.assertEqual(lazy_import.ScopeReplacer,

                         object.__getattribute__(test_scope1, '__class__'))

        self.assertEqual('foo', test_scope1.foo(1))

        self.assertIsInstance(test_scope1, TestClass)

        final_globals = set(globals().keys())

        self.assertEqual(set(['test_scope1']), new_globals - orig_globals)

        self.assertEqual(set(), orig_globals - new_globals)

        self.assertEqual(set(), final_globals - new_globals)

        self.assertEqual(set(), new_globals - final_globals)

    def test_class(self):

        actions = []

        InstrumentedReplacer.use_actions(actions)

        TestClass.use_actions(actions)

        def factory(replacer, scope, name):

            actions.append('factory')

            return TestClass

        try:

            test_class1

        except NameError:

            # test_class2 shouldn't exist yet

            pass

        else:

            self.fail('test_class1 was not supposed to exist yet')

        InstrumentedReplacer(scope=globals(), name='test_class1',

                             factory=factory)

        self.assertEqual('class_member', test_class1.class_member)

        self.assertEqual(test_class1, TestClass)

        self.assertEqual([('__getattribute__', 'class_member'),

                          '_replace',

                          'factory',

                         ], actions)

    def test_call_class(self):

        actions = []

        InstrumentedReplacer.use_actions(actions)

        TestClass.use_actions(actions)

        def factory(replacer, scope, name):

            actions.append('factory')

            return TestClass

        try:

            test_class2

        except NameError:

            # test_class2 shouldn't exist yet

            pass

        else:

            self.fail('test_class2 was not supposed to exist yet')

        InstrumentedReplacer(scope=globals(), name='test_class2',

                             factory=factory)

        self.assertFalse(test_class2 is TestClass)

        obj = test_class2()

        self.assertIs(test_class2, TestClass)

        self.assertIsInstance(obj, TestClass)

        self.assertEqual('class_member', obj.class_member)

        self.assertEqual([('__call__', (), {}),

                          '_replace',

                          'factory',

                          'init',

                         ], actions)

    def test_call_func(self):

        actions = []

        InstrumentedReplacer.use_actions(actions)

        def func(a, b, c=None):

            actions.append('func')

            return (a, b, c)

        def factory(replacer, scope, name):

            actions.append('factory')

            return func

        try:

            test_func1

        except NameError:

            # test_func1 shouldn't exist yet

            pass

        else:

            self.fail('test_func1 was not supposed to exist yet')

        InstrumentedReplacer(scope=globals(), name='test_func1',

                             factory=factory)

        self.assertFalse(test_func1 is func)

        val = test_func1(1, 2, c='3')

        self.assertIs(test_func1, func)

        self.assertEqual((1,2,'3'), val)

        self.assertEqual([('__call__', (1,2), {'c':'3'}),

                          '_replace',

                          'factory',

                          'func',

                         ], actions)

    def test_other_variable(self):

        """Test when a ScopeReplacer is assigned to another variable.

        This test could be updated if we find a way to trap '=' rather

        than just giving a belated exception.

        ScopeReplacer only knows about the variable it was created as,

        so until the object is replaced, it is illegal to pass it to

        another variable. (Though discovering this may take a while)

        """

        actions = []

        InstrumentedReplacer.use_actions(actions)

        TestClass.use_actions(actions)

        def factory(replacer, scope, name):

            actions.append('factory')

            return TestClass()

        try:

            test_obj2

        except NameError:

            # test_obj2 shouldn't exist yet

            pass

        else:

            self.fail('test_obj2 was not supposed to exist yet')

        InstrumentedReplacer(scope=globals(), name='test_obj2',

                             factory=factory)

        self.assertEqual(InstrumentedReplacer,

                         object.__getattribute__(test_obj2, '__class__'))

        # This is technically not allowed, but we don't have a way to

        # test it until later.

        test_obj3 = test_obj2

        self.assertEqual(InstrumentedReplacer,

                         object.__getattribute__(test_obj2, '__class__'))

        self.assertEqual(InstrumentedReplacer,

                         object.__getattribute__(test_obj3, '__class__'))

        # The first use of the alternate variable causes test_obj2 to

        # be replaced.

        self.assertEqual('foo', test_obj3.foo(1))

        # test_obj2 has been replaced, but the ScopeReplacer has no

        # idea of test_obj3

        self.assertEqual(TestClass,

                         object.__getattribute__(test_obj2, '__class__'))

        self.assertEqual(InstrumentedReplacer,

                         object.__getattribute__(test_obj3, '__class__'))

        # We should be able to access test_obj2 attributes normally

        self.assertEqual('foo', test_obj2.foo(2))

        self.assertEqual('foo', test_obj2.foo(3))

        # However, the next access on test_obj3 should raise an error

        # because only now are we able to detect the problem.

        self.assertRaises(errors.IllegalUseOfScopeReplacer,

                          getattr, test_obj3, 'foo')

        self.assertEqual([('__getattribute__', 'foo'),

                          '_replace',

                          'factory',

                          'init',

                          ('foo', 1),

                          ('foo', 2),

                          ('foo', 3),

                          ('__getattribute__', 'foo'),

                          '_replace',

                         ], actions)

    def test_enable_proxying(self):

        """Test that we can allow ScopeReplacer to proxy."""

        actions = []

        InstrumentedReplacer.use_actions(actions)

        TestClass.use_actions(actions)

        def factory(replacer, scope, name):

            actions.append('factory')

            return TestClass()

        try:

            test_obj4

        except NameError:

            # test_obj4 shouldn't exist yet

            pass

        else:

            self.fail('test_obj4 was not supposed to exist yet')

        lazy_import.ScopeReplacer._should_proxy = True

        InstrumentedReplacer(scope=globals(), name='test_obj4',

                             factory=factory)

        self.assertEqual(InstrumentedReplacer,

                         object.__getattribute__(test_obj4, '__class__'))

        test_obj5 = test_obj4

        self.assertEqual(InstrumentedReplacer,

                         object.__getattribute__(test_obj4, '__class__'))

        self.assertEqual(InstrumentedReplacer,

                         object.__getattribute__(test_obj5, '__class__'))

        # The first use of the alternate variable causes test_obj2 to

        # be replaced.

        self.assertEqual('foo', test_obj4.foo(1))

        self.assertEqual(TestClass,

                         object.__getattribute__(test_obj4, '__class__'))

        self.assertEqual(InstrumentedReplacer,

                         object.__getattribute__(test_obj5, '__class__'))

        # We should be able to access test_obj4 attributes normally

        self.assertEqual('foo', test_obj4.foo(2))

        # because we enabled proxying, test_obj5 can access its members as well

        self.assertEqual('foo', test_obj5.foo(3))

        self.assertEqual('foo', test_obj5.foo(4))

        # However, it cannot be replaced by the ScopeReplacer

        self.assertEqual(InstrumentedReplacer,

                         object.__getattribute__(test_obj5, '__class__'))

        self.assertEqual([('__getattribute__', 'foo'),

                          '_replace',

                          'factory',

                          'init',

                          ('foo', 1),

                          ('foo', 2),

                          ('__getattribute__', 'foo'),

                          ('foo', 3),

                          ('__getattribute__', 'foo'),

                          ('foo', 4),

                         ], actions)

    def test_replacing_from_own_scope_fails(self):

        """If a ScopeReplacer tries to replace itself a nice error is given"""

        actions = []

        InstrumentedReplacer.use_actions(actions)

        TestClass.use_actions(actions)

        def factory(replacer, scope, name):

            actions.append('factory')

            # return the name in given scope, which is currently the replacer

            return scope[name]

        try:

            test_obj7

        except NameError:

            # test_obj7 shouldn't exist yet

            pass

        else:

            self.fail('test_obj7 was not supposed to exist yet')

        InstrumentedReplacer(scope=globals(), name='test_obj7',

                             factory=factory)

        self.assertEqual(InstrumentedReplacer,

                         object.__getattribute__(test_obj7, '__class__'))

        e = self.assertRaises(errors.IllegalUseOfScopeReplacer, test_obj7)

        self.assertIn("replace itself", e.msg)

        self.assertEqual([('__call__', (), {}),

                          '_replace',

                          'factory'], actions)

class ImportReplacerHelper(TestCaseInTempDir):

    """Test the ability to have a lazily imported module or object"""

    def setUp(self):

        TestCaseInTempDir.setUp(self)

        self.create_modules()

        base_path = self.test_dir + '/base'

        self.actions = []

        InstrumentedImportReplacer.use_actions(self.actions)

        sys.path.append(base_path)

        self.addCleanup(sys.path.remove, base_path)

        original_import = __import__

        def instrumented_import(mod, scope1, scope2, fromlist):

            self.actions.append(('import', mod, fromlist))

            return original_import(mod, scope1, scope2, fromlist)

        def cleanup():

            __builtins__['__import__'] = original_import

        self.addCleanup(cleanup)

        __builtins__['__import__'] = instrumented_import

    def create_modules(self):

        """Create some random modules to be imported.

        Each entry has a random suffix, and the full names are saved

        These are setup as follows:

         base/ <= used to ensure not in default search path

            root-XXX/

                __init__.py <= This will contain var1, func1

                mod-XXX.py <= This will contain var2, func2

                sub-XXX/

                    __init__.py <= Contains var3, func3

                    submoda-XXX.py <= contains var4, func4

                    submodb-XXX.py <= containse var5, func5

        """

        rand_suffix = osutils.rand_chars(4)

        root_name = 'root_' + rand_suffix

        mod_name = 'mod_' + rand_suffix

        sub_name = 'sub_' + rand_suffix

        submoda_name = 'submoda_' + rand_suffix

        submodb_name = 'submodb_' + rand_suffix

        os.mkdir('base')

        root_path = osutils.pathjoin('base', root_name)

        os.mkdir(root_path)

        root_init = osutils.pathjoin(root_path, '__init__.py')

        f = open(osutils.pathjoin(root_path, '__init__.py'), 'wb')

        try:

            f.write('var1 = 1\ndef func1(a):\n  return a\n')

        finally:

            f.close()

        mod_path = osutils.pathjoin(root_path, mod_name + '.py')

        f = open(mod_path, 'wb')

        try:

            f.write('var2 = 2\ndef func2(a):\n  return a\n')

        finally:

            f.close()

        sub_path = osutils.pathjoin(root_path, sub_name)

        os.mkdir(sub_path)

        f = open(osutils.pathjoin(sub_path, '__init__.py'), 'wb')

        try:

            f.write('var3 = 3\ndef func3(a):\n  return a\n')

        finally:

            f.close()

        submoda_path = osutils.pathjoin(sub_path, submoda_name + '.py')

        f = open(submoda_path, 'wb')

        try:

            f.write('var4 = 4\ndef func4(a):\n  return a\n')

        finally:

            f.close()

        submodb_path = osutils.pathjoin(sub_path, submodb_name + '.py')

        f = open(submodb_path, 'wb')

        try:

            f.write('var5 = 5\ndef func5(a):\n  return a\n')

        finally:

            f.close()

        self.root_name = root_name

        self.mod_name = mod_name

        self.sub_name = sub_name

        self.submoda_name = submoda_name

        self.submodb_name = submodb_name

class TestImportReplacerHelper(ImportReplacerHelper):

    def test_basic_import(self):

        """Test that a real import of these modules works"""

        sub_mod_path = '.'.join([self.root_name, self.sub_name,

                                  self.submoda_name])

        root = __import__(sub_mod_path, globals(), locals(), [])

        self.assertEqual(1, root.var1)

        self.assertEqual(3, getattr(root, self.sub_name).var3)

        self.assertEqual(4, getattr(getattr(root, self.sub_name),

                                    self.submoda_name).var4)

        mod_path = '.'.join([self.root_name, self.mod_name])

        root = __import__(mod_path, globals(), locals(), [])

        self.assertEqual(2, getattr(root, self.mod_name).var2)

        self.assertEqual([('import', sub_mod_path, []),

                          ('import', mod_path, []),

                         ], self.actions)

class TestImportReplacer(ImportReplacerHelper):

    def test_import_root(self):

        """Test 'import root-XXX as root1'"""

        try:

            root1

        except NameError:

            # root1 shouldn't exist yet

            pass

        else:

            self.fail('root1 was not supposed to exist yet')

        # This should replicate 'import root-xxyyzz as root1'

        InstrumentedImportReplacer(scope=globals(), name='root1',

                                   module_path=[self.root_name],

                                   member=None, children={})

        self.assertEqual(InstrumentedImportReplacer,

                         object.__getattribute__(root1, '__class__'))

        self.assertEqual(1, root1.var1)

        self.assertEqual('x', root1.func1('x'))

        self.assertEqual([('__getattribute__', 'var1'),

                          '_replace',

                          ('_import', 'root1'),

                          ('import', self.root_name, []),

                         ], self.actions)

    def test_import_mod(self):

        """Test 'import root-XXX.mod-XXX as mod2'"""

        try:

            mod1

        except NameError:

            # mod1 shouldn't exist yet

            pass

        else:

            self.fail('mod1 was not supposed to exist yet')

        mod_path = self.root_name + '.' + self.mod_name

        InstrumentedImportReplacer(scope=globals(), name='mod1',

                                   module_path=[self.root_name, self.mod_name],

                                   member=None, children={})

        self.assertEqual(InstrumentedImportReplacer,

                         object.__getattribute__(mod1, '__class__'))

        self.assertEqual(2, mod1.var2)

        self.assertEqual('y', mod1.func2('y'))

        self.assertEqual([('__getattribute__', 'var2'),

                          '_replace',

                          ('_import', 'mod1'),

                          ('import', mod_path, []),

                         ], self.actions)

    def test_import_mod_from_root(self):

        """Test 'from root-XXX import mod-XXX as mod2'"""

        try:

            mod2

        except NameError:

            # mod2 shouldn't exist yet

            pass

        else:

            self.fail('mod2 was not supposed to exist yet')

        InstrumentedImportReplacer(scope=globals(), name='mod2',

                                   module_path=[self.root_name],

                                   member=self.mod_name, children={})

        self.assertEqual(InstrumentedImportReplacer,

                         object.__getattribute__(mod2, '__class__'))

        self.assertEqual(2, mod2.var2)

        self.assertEqual('y', mod2.func2('y'))

        self.assertEqual([('__getattribute__', 'var2'),

                          '_replace',

                          ('_import', 'mod2'),

                          ('import', self.root_name, [self.mod_name]),

                         ], self.actions)

    def test_import_root_and_mod(self):

        """Test 'import root-XXX.mod-XXX' remapping both to root3.mod3"""

        try:

            root3

        except NameError:

            # root3 shouldn't exist yet

            pass

        else:

            self.fail('root3 was not supposed to exist yet')

        InstrumentedImportReplacer(scope=globals(),

            name='root3', module_path=[self.root_name], member=None,

            children={'mod3':([self.root_name, self.mod_name], None, {})})

        # So 'root3' should be a lazy import

        # and once it is imported, mod3 should also be lazy until

        # actually accessed.

        self.assertEqual(InstrumentedImportReplacer,

                         object.__getattribute__(root3, '__class__'))

        self.assertEqual(1, root3.var1)

        # There is a mod3 member, but it is also lazy

        self.assertEqual(InstrumentedImportReplacer,

                         object.__getattribute__(root3.mod3, '__class__'))

        self.assertEqual(2, root3.mod3.var2)

        mod_path = self.root_name + '.' + self.mod_name

        self.assertEqual([('__getattribute__', 'var1'),

                          '_replace',

                          ('_import', 'root3'),

                          ('import', self.root_name, []),

                          ('__getattribute__', 'var2'),

                          '_replace',

                          ('_import', 'mod3'),

                          ('import', mod_path, []),

                         ], self.actions)

    def test_import_root_and_root_mod(self):

        """Test that 'import root, root.mod' can be done.

        The second import should re-use the first one, and just add

        children to be imported.

        """

        try:

            root4

        except NameError:

            # root4 shouldn't exist yet

            pass

        else:

            self.fail('root4 was not supposed to exist yet')

        InstrumentedImportReplacer(scope=globals(),

            name='root4', module_path=[self.root_name], member=None,

            children={})

        # So 'root4' should be a lazy import

        self.assertEqual(InstrumentedImportReplacer,

                         object.__getattribute__(root4, '__class__'))

        # Lets add a new child to be imported on demand

        # This syntax of using object.__getattribute__ is the correct method

        # for accessing the _import_replacer_children member

        children = object.__getattribute__(root4, '_import_replacer_children')

        children['mod4'] = ([self.root_name, self.mod_name], None, {})

        # Accessing root4.mod4 should import root, but mod should stay lazy

        self.assertEqual(InstrumentedImportReplacer,

                         object.__getattribute__(root4.mod4, '__class__'))

        self.assertEqual(2, root4.mod4.var2)

        mod_path = self.root_name + '.' + self.mod_name

        self.assertEqual([('__getattribute__', 'mod4'),

                          '_replace',

                          ('_import', 'root4'),

                          ('import', self.root_name, []),

                          ('__getattribute__', 'var2'),

                          '_replace',

                          ('_import', 'mod4'),

                          ('import', mod_path, []),

                         ], self.actions)

    def test_import_root_sub_submod(self):