# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.
#

"""
Classes and functions used by L{twisted.trial.test.test_util}
and L{twisted.trial.test.test_loader}.
"""

from __future__ import division, absolute_import

import sys
import os

from twisted.python.compat import _PY3
from twisted.trial import unittest

if _PY3:
    # Python 3 has some funny import caching, which we don't want.
    # invalidate_caches clears it out for us.
    from importlib import invalidate_caches as invalidateImportCaches
else:
    def invalidateImportCaches():
        """
        On python 2, import caches don't need to be invalidated.
        """

testModule = """
from twisted.trial import unittest

class FooTest(unittest.SynchronousTestCase):
    def testFoo(self):
        pass
"""

dosModule = testModule.replace('\n', '\r\n')


testSample = """
'''This module is used by test_loader to test the Trial test loading
functionality. Do NOT change the number of tests in this module.
Do NOT change the names the tests in this module.
'''

import unittest as pyunit
from twisted.trial import unittest

class FooTest(unittest.SynchronousTestCase):
    def test_foo(self):
        pass

    def test_bar(self):
        pass


class PyunitTest(pyunit.TestCase):
    def test_foo(self):
        pass

    def test_bar(self):
        pass


class NotATest(object):
    def test_foo(self):
        pass


class AlphabetTest(unittest.SynchronousTestCase):
    def test_a(self):
        pass

    def test_b(self):
        pass

    def test_c(self):
        pass
"""

testInheritanceSample = """
'''This module is used by test_loader to test the Trial test loading
functionality. Do NOT change the number of tests in this module.
Do NOT change the names the tests in this module.
'''

from twisted.trial import unittest

class X(object):

    def test_foo(self):
        pass

class A(unittest.SynchronousTestCase, X):
    pass

class B(unittest.SynchronousTestCase, X):
    pass

"""

class PackageTest(unittest.SynchronousTestCase):
    files = [
        ('badpackage/__init__.py', 'frotz\n'),
        ('badpackage/test_module.py', ''),
        ('unimportablepackage/__init__.py', ''),
        ('unimportablepackage/test_module.py', 'import notarealmoduleok\n'),
        ('package2/__init__.py', ''),
        ('package2/test_module.py', 'import frotz\n'),
        ('package/__init__.py', ''),
        ('package/frotz.py', 'frotz\n'),
        ('package/test_bad_module.py',
         'raise ZeroDivisionError("fake error")'),
        ('package/test_dos_module.py', dosModule),
        ('package/test_import_module.py', 'import frotz'),
        ('package/test_module.py', testModule),
        ('goodpackage/__init__.py', ''),
        ('goodpackage/test_sample.py', testSample),
        ('goodpackage/sub/__init__.py', ''),
        ('goodpackage/sub/test_sample.py', testSample),
        ('inheritancepackage/__init__.py', ''),
        ('inheritancepackage/test_x.py', testInheritanceSample),
        ]


    def _toModuleName(self, filename):
        name = os.path.splitext(filename)[0]
        segs = name.split('/')
        if segs[-1] == '__init__':
            segs = segs[:-1]
        return '.'.join(segs)


    def getModules(self):
        """
        Return matching module names for files listed in C{self.files}.
        """
        return [self._toModuleName(filename) for (filename, code) in self.files]


    def cleanUpModules(self):
        modules = self.getModules()
        modules.sort()
        modules.reverse()
        for module in modules:
            try:
                del sys.modules[module]
            except KeyError:
                pass


    def createFiles(self, files, parentDir='.'):
        for filename, contents in self.files:
            filename = os.path.join(parentDir, filename)
            self._createDirectory(filename)
            with open(filename, 'w') as fd:
                fd.write(contents)


    def _createDirectory(self, filename):
        directory = os.path.dirname(filename)
        if not os.path.exists(directory):
            os.makedirs(directory)


    def setUp(self, parentDir=None):
        invalidateImportCaches()
        if parentDir is None:
            parentDir = self.mktemp()
        self.parent = parentDir
        self.createFiles(self.files, parentDir)


    def tearDown(self):
        self.cleanUpModules()



class SysPathManglingTest(PackageTest):
    def setUp(self, parent=None):
        invalidateImportCaches()
        self.oldPath = sys.path[:]
        self.newPath = sys.path[:]
        if parent is None:
            parent = self.mktemp()
        PackageTest.setUp(self, parent)
        self.newPath.append(self.parent)
        self.mangleSysPath(self.newPath)


    def tearDown(self):
        PackageTest.tearDown(self)
        self.mangleSysPath(self.oldPath)


    def mangleSysPath(self, pathVar):
        sys.path[:] = pathVar