def __init__(self,
                 topsrcdir='/path/to/topsrcdir',
                 extra_substs={},
                 error_is_fatal=True,
             ):
        self.topsrcdir = mozpath.abspath(topsrcdir)
        self.topobjdir = mozpath.abspath('/path/to/topobjdir')

        self.substs = ReadOnlyDict({
            'MOZ_FOO': 'foo',
            'MOZ_BAR': 'bar',
            'MOZ_TRUE': '1',
            'MOZ_FALSE': '',
            'DLL_PREFIX': 'lib',
            'DLL_SUFFIX': '.so'
        }, **extra_substs)

        self.substs_unicode = ReadOnlyDict({k.decode('utf-8'): v.decode('utf-8',
            'replace') for k, v in self.substs.items()})

        self.defines = self.substs

        self.external_source_dir = None
        self.lib_prefix = 'lib'
        self.lib_suffix = '.a'
        self.import_prefix = 'lib'
        self.import_suffix = '.so'
        self.dll_prefix = 'lib'
        self.dll_suffix = '.so'
        self.error_is_fatal = error_is_fatal

    def __init__(self, paths, config, environ, *args, **kwargs):
        self._search_path = environ.get('PATH', '').split(os.pathsep)

        self._subprocess_paths = {
            mozpath.abspath(k): v for k, v in paths.iteritems() if v
        }

        paths = paths.keys()

        environ = dict(environ)
        if 'CONFIG_SHELL' not in environ:
            environ['CONFIG_SHELL'] = mozpath.abspath('/bin/sh')
            self._subprocess_paths[environ['CONFIG_SHELL']] = self.shell
            paths.append(environ['CONFIG_SHELL'])
        self._environ = copy.copy(environ)

        vfs = ConfigureTestVFS(paths)

        self.OS = ReadOnlyNamespace(path=ReadOnlyNamespace(**{
            k: v if k not in ('exists', 'isfile')
            else getattr(vfs, k)
            for k, v in ConfigureSandbox.OS.path.__dict__.iteritems()
        }))

        super(ConfigureTestSandbox, self).__init__(config, environ, *args,
                                                   **kwargs)

    def __init__(self, paths, config, environ, *args, **kwargs):
        self._search_path = environ.get('PATH', '').split(os.pathsep)

        self._subprocess_paths = {
            mozpath.abspath(k): v for k, v in paths.iteritems() if v
        }

        paths = paths.keys()

        environ = dict(environ)
        if 'CONFIG_SHELL' not in environ:
            environ['CONFIG_SHELL'] = mozpath.abspath('/bin/sh')
            self._subprocess_paths[environ['CONFIG_SHELL']] = self.shell
            paths.append(environ['CONFIG_SHELL'])
        self._environ = copy.copy(environ)

        vfs = ConfigureTestVFS(paths)

        os_path = {
            k: getattr(vfs, k) for k in dir(vfs) if not k.startswith('_')
        }

        os_path.update(self.OS.path.__dict__)

        self.imported_os = ReadOnlyNamespace(path=ReadOnlyNamespace(**os_path))

        super(ConfigureTestSandbox, self).__init__(config, environ, *args,
                                                   **kwargs)

    def test_mismatched_compiler(self):
        self.do_toolchain_test(self.PATHS, {
            'c_compiler': self.GCC_4_9_RESULT,
            'cxx_compiler': (
                'The target C compiler is gcc, while the target C++ compiler '
                'is clang. Need to use the same compiler suite.'),
        }, environ={
            'CXX': 'clang++',
        })

        self.do_toolchain_test(self.PATHS, {
            'c_compiler': self.GCC_4_9_RESULT,
            'cxx_compiler': self.GXX_4_9_RESULT,
            'host_c_compiler': self.GCC_4_9_RESULT,
            'host_cxx_compiler': (
                'The host C compiler is gcc, while the host C++ compiler '
                'is clang. Need to use the same compiler suite.'),
        }, environ={
            'HOST_CXX': 'clang++',
        })

        self.do_toolchain_test(self.PATHS, {
            'c_compiler': '`%s` is not a C compiler.'
            % mozpath.abspath('/usr/bin/g++'),
        }, environ={
            'CC': 'g++',
        })

        self.do_toolchain_test(self.PATHS, {
            'c_compiler': self.GCC_4_9_RESULT,
            'cxx_compiler': '`%s` is not a C++ compiler.'
            % mozpath.abspath('/usr/bin/gcc'),
        }, environ={
            'CXX': 'gcc',
        })

    def setUpClass(cls):
        class Config(object):
            pass

        cls.config = config = Config()
        config.topsrcdir = mozpath.abspath(os.curdir)
        config.topobjdir = mozpath.abspath("obj")
        config.external_source_dir = None

    def test_exec_source_success(self):
        sandbox = self.sandbox()
        context = sandbox._context

        sandbox.exec_source("foo = True", mozpath.abspath("foo.py"))

        self.assertNotIn("foo", context)
        self.assertEqual(context.main_path, mozpath.abspath("foo.py"))
        self.assertEqual(context.all_paths, set([mozpath.abspath("foo.py")]))

    def test_exec_compile_error(self):
        sandbox = self.sandbox()

        with self.assertRaises(SandboxExecutionError) as se:
            sandbox.exec_source("2f23;k;asfj", mozpath.abspath("foo.py"))

        self.assertEqual(se.exception.file_stack, [mozpath.abspath("foo.py")])
        self.assertIsInstance(se.exception.exc_value, SyntaxError)
        self.assertEqual(sandbox._context.main_path, mozpath.abspath("foo.py"))

    def test_default_state(self):
        sandbox = self.sandbox()
        config = sandbox.config

        self.assertEqual(sandbox['TOPSRCDIR'], config.topsrcdir)
        self.assertEqual(sandbox['TOPOBJDIR'],
            mozpath.abspath(config.topobjdir))
        self.assertEqual(sandbox['RELATIVEDIR'], '')
        self.assertEqual(sandbox['SRCDIR'], config.topsrcdir)
        self.assertEqual(sandbox['OBJDIR'],
            mozpath.abspath(config.topobjdir).replace(os.sep, '/'))

    def test_compiler_result(self):
        result = CompilerResult()
        self.assertEquals(result.__dict__, {
            'wrapper': [],
            'compiler': mozpath.abspath(''),
            'version': '',
            'type': '',
            'language': '',
            'flags': [],
        })

        result = CompilerResult(
            compiler='/usr/bin/gcc',
            version='4.2.1',
            type='gcc',
            language='C',
            flags=['-std=gnu99'],
        )
        self.assertEquals(result.__dict__, {
            'wrapper': [],
            'compiler': mozpath.abspath('/usr/bin/gcc'),
            'version': '4.2.1',
            'type': 'gcc',
            'language': 'C',
            'flags': ['-std=gnu99'],
        })

        result2 = result + {'flags': ['-m32']}
        self.assertEquals(result2.__dict__, {
            'wrapper': [],
            'compiler': mozpath.abspath('/usr/bin/gcc'),
            'version': '4.2.1',
            'type': 'gcc',
            'language': 'C',
            'flags': ['-std=gnu99', '-m32'],
        })
        # Original flags are untouched.
        self.assertEquals(result.flags, ['-std=gnu99'])

        result3 = result + {
            'compiler': '/usr/bin/gcc-4.7',
            'version': '4.7.3',
            'flags': ['-m32'],
        }
        self.assertEquals(result3.__dict__, {
            'wrapper': [],
            'compiler': mozpath.abspath('/usr/bin/gcc-4.7'),
            'version': '4.7.3',
            'type': 'gcc',
            'language': 'C',
            'flags': ['-std=gnu99', '-m32'],
        })

    def _get_files_info(self, paths):
        from mozpack.files import FileFinder

        # Normalize to relative from topsrcdir.
        relpaths = []
        for p in paths:
            a = mozpath.abspath(p)
            if not mozpath.basedir(a, [self.topsrcdir]):
                raise InvalidPathException('path is outside topsrcdir: %s' % p)

            relpaths.append(mozpath.relpath(a, self.topsrcdir))

        finder = FileFinder(self.topsrcdir, find_executables=False)

        # Expand wildcards.
        allpaths = []
        for p in relpaths:
            if '*' not in p:
                if p not in allpaths:
                    allpaths.append(p)
                continue

            for path, f in finder.find(p):
                if path not in allpaths:
                    allpaths.append(path)

        reader = self._get_reader()
        return reader.files_info(allpaths)

    def include_file(self, path):
        '''Include one file in the sandbox. Users of this class probably want

        Note: this will execute all template invocations, as well as @depends
        functions that depend on '--help', but nothing else.
        '''

        if self._paths:
            path = mozpath.join(mozpath.dirname(self._paths[-1]), path)
            path = mozpath.normpath(path)
            if not mozpath.basedir(path, (mozpath.dirname(self._paths[0]),)):
                raise ConfigureError(
                    'Cannot include `%s` because it is not in a subdirectory '
                    'of `%s`' % (path, mozpath.dirname(self._paths[0])))
        else:
            path = mozpath.realpath(mozpath.abspath(path))
        if path in self._all_paths:
            raise ConfigureError(
                'Cannot include `%s` because it was included already.' % path)
        self._paths.append(path)
        self._all_paths.add(path)

        source = open(path, 'rb').read()

        code = compile(source, path, 'exec')

        exec_(code, self)

        self._paths.pop(-1)

    def test_imply_option_immediate_value(self):
        def get_config(*args):
            return self.get_config(
                *args, configure='imply_option/imm.configure')

        help, config = get_config(['--help'])
        self.assertEquals(config, {})

        config = get_config([])
        self.assertEquals(config, {})

        config_path = mozpath.abspath(
            mozpath.join(test_data_path, 'imply_option', 'imm.configure'))

        with self.assertRaisesRegexp(InvalidOptionError,
            "--enable-foo' implied by 'imply_option at %s:7' conflicts with "
            "'--disable-foo' from the command-line" % config_path):
            get_config(['--disable-foo'])

        with self.assertRaisesRegexp(InvalidOptionError,
            "--enable-bar=foo,bar' implied by 'imply_option at %s:16' conflicts"
            " with '--enable-bar=a,b,c' from the command-line" % config_path):
            get_config(['--enable-bar=a,b,c'])

        with self.assertRaisesRegexp(InvalidOptionError,
            "--enable-baz=BAZ' implied by 'imply_option at %s:25' conflicts"
            " with '--enable-baz=QUUX' from the command-line" % config_path):
            get_config(['--enable-baz=QUUX'])

 def which(self, command, path=None):
     for parent in (path or self._search_path):
         c = mozpath.abspath(mozpath.join(parent, command))
         for candidate in (c, ensure_exe_extension(c)):
             if self.imported_os.path.exists(candidate):
                 return candidate
     raise WhichError()

 def isfile(self, path):
     path = mozpath.abspath(path)
     if path in self._paths:
         return True
     if mozpath.basedir(path, [topsrcdir, topobjdir]):
         return os.path.isfile(path)
     return False

    def do_toolchain_test(self, paths, results, args=[], environ={}):
        '''Helper to test the toolchain checks from toolchain.configure.

        - `paths` is a dict associating compiler paths to FakeCompiler
          definitions from above.
        - `results` is a dict associating result variable names from
          toolchain.configure (c_compiler, cxx_compiler, host_c_compiler,
          host_cxx_compiler) with a result.
          The result can either be an error string, or a dict with the
          following items: flags, version, type, compiler, wrapper. (wrapper
          can be omitted when it's empty). Those items correspond to the
          attributes of the object returned by toolchain.configure checks
          and will be compared to them.
          When the results for host_c_compiler are identical to c_compiler,
          they can be omitted. Likewise for host_cxx_compiler vs.
          cxx_compiler.
        '''
        environ = dict(environ)
        if 'PATH' not in environ:
            environ['PATH'] = os.pathsep.join(
                mozpath.abspath(p) for p in ('/bin', '/usr/bin'))

        sandbox = self.get_sandbox(paths, {}, args, environ,
                                   logger=self.logger)

        for var in ('c_compiler', 'cxx_compiler', 'host_c_compiler',
                    'host_cxx_compiler'):
            if var in results:
                result = results[var]
            elif var.startswith('host_'):
                result = results.get(var[5:], {})
            else:
                result = {}
            if isinstance(result, dict):
                result = dict(result)
                result.setdefault('wrapper', [])
                result['compiler'] = mozpath.abspath(result['compiler'])
            try:
                self.out.truncate(0)
                compiler = sandbox._value_for(sandbox[var])
                # Add var on both ends to make it clear which of the
                # variables is failing the test when that happens.
                self.assertEquals((var, compiler.__dict__), (var, result))
            except SystemExit:
                self.assertEquals((var, result),
                                  (var, self.out.getvalue().strip()))
                return

    def __init__(self, topsrcdir='/path/to/topsrcdir', extra_substs={}):
        self.topsrcdir = mozpath.abspath(topsrcdir)
        self.topobjdir = mozpath.abspath('/path/to/topobjdir')

        self.substs = ReadOnlyDict({
            'MOZ_FOO': 'foo',
            'MOZ_BAR': 'bar',
            'MOZ_TRUE': '1',
            'MOZ_FALSE': '',
        }, **extra_substs)

        self.substs_unicode = ReadOnlyDict({k.decode('utf-8'): v.decode('utf-8',
            'replace') for k, v in self.substs.items()})

        self.defines = self.substs

        self.external_source_dir = None

        def get_value_for(args=[], environ={}, mozconfig=""):
            sandbox = self.get_sandbox({}, {}, args, environ, mozconfig)

            # Add a fake old-configure option
            sandbox.option_impl("--with-foo", nargs="*", help="Help missing for old configure options")

            result = sandbox._value_for(sandbox["all_configure_options"])
            shell = mozpath.abspath("/bin/sh")
            return result.replace("CONFIG_SHELL=%s " % shell, "")

    def test_path_calculation(self):
        sandbox = self.sandbox('foo/bar/moz.build')
        config = sandbox.config

        self.assertEqual(sandbox['RELATIVEDIR'], 'foo/bar')
        self.assertEqual(sandbox['SRCDIR'], '/'.join([config.topsrcdir,
            'foo/bar']))
        self.assertEqual(sandbox['OBJDIR'],
            mozpath.abspath('/'.join([config.topobjdir, 'foo/bar'])).replace(os.sep, '/'))

        def get_value_for(args=[], environ={}, mozconfig=''):
            sandbox = self.get_sandbox({}, {}, args, environ, mozconfig)

            # Add a fake old-configure option
            sandbox.option_impl('--with-foo', nargs='*',
                                help='Help missing for old configure options')

            result = sandbox._value_for(sandbox['all_configure_options'])
            shell = mozpath.abspath('/bin/sh')
            return result.replace('CONFIG_SHELL=%s ' % shell, '')

    def test_dirs(self):
        class Config(object): pass
        config = Config()
        config.topsrcdir = mozpath.abspath(os.curdir)
        config.topobjdir = mozpath.abspath('obj')
        test = Context(config=config)
        foo = mozpath.abspath('foo')
        test.push_source(foo)

        self.assertEqual(test.srcdir, config.topsrcdir)
        self.assertEqual(test.relsrcdir, '')
        self.assertEqual(test.objdir, config.topobjdir)
        self.assertEqual(test.relobjdir, '')

        foobar = os.path.abspath('foo/bar')
        test.push_source(foobar)
        self.assertEqual(test.srcdir, mozpath.join(config.topsrcdir, 'foo'))
        self.assertEqual(test.relsrcdir, 'foo')
        self.assertEqual(test.objdir, config.topobjdir)
        self.assertEqual(test.relobjdir, '')