diff --git a/conftest.py b/conftest.py
index 81d0fe54..91e772b3 100644
--- a/conftest.py
+++ b/conftest.py
@@ -9,6 +9,7 @@ import pytest
 import jedi
 from jedi.api.environment import get_system_environment, InterpreterEnvironment
 from jedi._compatibility import py_version
+from test.helpers import test_dir
 
 collect_ignore = [
     'setup.py',
@@ -109,6 +110,12 @@ def Script(environment):
     return partial(jedi.Script, environment=environment)
 
 
+@pytest.fixture(scope='session')
+def ScriptWithProject(Script):
+    project = jedi.Project(test_dir)
+    return partial(jedi.Script, project=project)
+
+
 @pytest.fixture(scope='session')
 def get_names(Script):
     return lambda code, **kwargs: Script(code).get_names(**kwargs)
diff --git a/jedi/__init__.py b/jedi/__init__.py
index f540b64e..b35f3ec3 100644
--- a/jedi/__init__.py
+++ b/jedi/__init__.py
@@ -41,6 +41,7 @@ from jedi import settings
 from jedi.api.environment import find_virtualenvs, find_system_environments, \
     get_default_environment, InvalidPythonEnvironment, create_environment, \
     get_system_environment, InterpreterEnvironment
+from jedi.api.project import Project, get_default_project
 from jedi.api.exceptions import InternalError
 # Finally load the internal plugins. This is only internal.
 from jedi.plugins import registry
diff --git a/jedi/api/__init__.py b/jedi/api/__init__.py
index 5f75410b..606b1254 100644
--- a/jedi/api/__init__.py
+++ b/jedi/api/__init__.py
@@ -30,6 +30,7 @@ from jedi.api.completion import Completion
 from jedi.api.keywords import KeywordName
 from jedi.api.environment import InterpreterEnvironment
 from jedi.api.project import get_default_project, Project
+from jedi.api.errors import parso_to_jedi_errors
 from jedi.inference import InferenceState
 from jedi.inference import imports
 from jedi.inference.references import find_references
@@ -87,7 +88,7 @@ class Script(object):
     """
     def __init__(self, source=None, line=None, column=None, path=None,
                  encoding='utf-8', sys_path=None, environment=None,
-                 _project=None):
+                 project=None):
         self._orig_path = path
         # An empty path (also empty string) should always result in no path.
         self.path = os.path.abspath(path) if path else None
@@ -103,15 +104,20 @@ class Script(object):
         if sys_path is not None and not is_py3:
             sys_path = list(map(force_unicode, sys_path))
 
-        project = _project
         if project is None:
             # Load the Python grammar of the current interpreter.
             project = get_default_project(
-                os.path.dirname(self.path)if path else os.getcwd()
+                os.path.dirname(self.path) if path else None
             )
         # TODO deprecate and remove sys_path from the Script API.
         if sys_path is not None:
             project._sys_path = sys_path
+            warnings.warn(
+                "Deprecated since version 0.17.0. Use the project API instead, "
+                "which means Script(project=Project(dir, sys_path=sys_path)) instead.",
+                DeprecationWarning,
+                stacklevel=2
+            )
         self._inference_state = InferenceState(
             project, environment=environment, script_path=self.path
         )
@@ -500,6 +506,9 @@ class Script(object):
         """
         return self._names(**kwargs)  # Python 2...
 
+    def get_syntax_errors(self):
+        return parso_to_jedi_errors(self._grammar, self._module_node)
+
     def _names(self, all_scopes=False, definitions=True, references=False):
         def def_ref_filter(_def):
             is_def = _def._name.tree_name.is_definition()
@@ -560,7 +569,7 @@ class Interpreter(Script):
                 raise TypeError("The environment needs to be an InterpreterEnvironment subclass.")
 
         super(Interpreter, self).__init__(source, environment=environment,
-                                          _project=Project(os.getcwd()), **kwds)
+                                          project=Project(os.getcwd()), **kwds)
         self.namespaces = namespaces
         self._inference_state.allow_descriptor_getattr = self._allow_descriptor_getattr_default
 
diff --git a/jedi/api/classes.py b/jedi/api/classes.py
index 643be840..a4978d1b 100644
--- a/jedi/api/classes.py
+++ b/jedi/api/classes.py
@@ -707,6 +707,16 @@ class Definition(BaseDefinition):
         else:
             return self._name.tree_name.is_definition()
 
+    def is_side_effect(self):
+        """
+        Checks if a name is defined as ``self.foo = 3``. In case of self, this
+        function would return False, for foo it would return True.
+        """
+        tree_name = self._name.tree_name
+        if tree_name is None:
+            return False
+        return tree_name.is_definition() and tree_name.parent.type == 'trailer'
+
     def __eq__(self, other):
         return self._name.start_pos == other._name.start_pos \
             and self.module_path == other.module_path \
diff --git a/jedi/api/errors.py b/jedi/api/errors.py
new file mode 100644
index 00000000..e86f9212
--- /dev/null
+++ b/jedi/api/errors.py
@@ -0,0 +1,36 @@
+"""
+This file is about errors in Python files and not about exception handling in
+Jedi.
+"""
+
+
+def parso_to_jedi_errors(grammar, module_node):
+    return [SyntaxError(e) for e in grammar.iter_errors(module_node)]
+
+
+class SyntaxError(object):
+    def __init__(self, parso_error):
+        self._parso_error = parso_error
+
+    @property
+    def line(self):
+        return self._parso_error.start_pos[0]
+
+    @property
+    def column(self):
+        return self._parso_error.start_pos[1]
+
+    @property
+    def until_line(self):
+        return self._parso_error.end_pos[0]
+
+    @property
+    def until_column(self):
+        return self._parso_error.end_pos[1]
+
+    def __repr__(self):
+        return '<%s from=%s to=%s>' % (
+            self.__class__.__name__,
+            self._parso_error.start_pos,
+            self._parso_error.end_pos,
+        )
diff --git a/jedi/api/project.py b/jedi/api/project.py
index 6b76c8dc..45e4c09a 100644
--- a/jedi/api/project.py
+++ b/jedi/api/project.py
@@ -1,9 +1,9 @@
 import os
+import errno
 import json
 
 from jedi._compatibility import FileNotFoundError, PermissionError, IsADirectoryError
-from jedi.api.environment import SameEnvironment, \
-    get_cached_default_environment
+from jedi.api.environment import get_cached_default_environment, create_environment
 from jedi.api.exceptions import WrongVersion
 from jedi._compatibility import force_unicode
 from jedi.inference.sys_path import discover_buildout_paths
@@ -30,13 +30,15 @@ def _force_unicode_list(lst):
 
 
 class Project(object):
-    # TODO serialize environment
-    _serializer_ignore_attributes = ('_environment',)
     _environment = None
 
+    @staticmethod
+    def _get_config_folder_path(base_path):
+        return os.path.join(base_path, _CONFIG_FOLDER)
+
     @staticmethod
     def _get_json_path(base_path):
-        return os.path.join(base_path, _CONFIG_FOLDER, 'project.json')
+        return os.path.join(Project._get_config_folder_path(base_path), 'project.json')
 
     @classmethod
     def load(cls, path):
@@ -47,9 +49,7 @@ class Project(object):
             version, data = json.load(f)
 
         if version == 1:
-            self = cls.__new__()
-            self.__dict__.update(data)
-            return self
+            return cls(**data)
         else:
             raise WrongVersion(
                 "The Jedi version of this project seems newer than what we can handle."
@@ -58,35 +58,40 @@ class Project(object):
     def __init__(self, path, **kwargs):
         """
         :param path: The base path for this project.
+        :param python_path: The Python executable path, typically the path of a
+            virtual environment.
+        :param load_unsafe_extensions: Loads extensions that are not in the
+            sys path and in the local directories. With this option enabled,
+            this is potentially unsafe if you clone a git repository and
+            analyze it's code, because those compiled extensions will be
+            important and therefore have execution privileges.
         :param sys_path: list of str. You can override the sys path if you
             want. By default the ``sys.path.`` is generated from the
             environment (virtualenvs, etc).
+        :param added_sys_path: list of str. Adds these paths at the end of the
+            sys path.
         :param smart_sys_path: If this is enabled (default), adds paths from
             local directories. Otherwise you will have to rely on your packages
             being properly configured on the ``sys.path``.
         """
-        def py2_comp(path, environment=None, sys_path=None,
-                     smart_sys_path=True, _django=False):
+        def py2_comp(path, python_path=None, load_unsafe_extensions=False,
+                     sys_path=None, added_sys_path=(), smart_sys_path=True):
             self._path = os.path.abspath(path)
-            if isinstance(environment, SameEnvironment):
-                self._environment = environment
 
+            self._python_path = python_path
             self._sys_path = sys_path
             self._smart_sys_path = smart_sys_path
-            self._django = _django
+            self._load_unsafe_extensions = load_unsafe_extensions
+            self._django = False
+            self.added_sys_path = list(added_sys_path)
+            """The sys path that is going to be added at the end of the """
 
         py2_comp(path, **kwargs)
 
     @inference_state_as_method_param_cache()
-    def _get_base_sys_path(self, inference_state, environment=None):
-        if self._sys_path is not None:
-            return self._sys_path
-
+    def _get_base_sys_path(self, inference_state):
         # The sys path has not been set explicitly.
-        if environment is None:
-            environment = self.get_environment()
-
-        sys_path = list(environment.get_sys_path())
+        sys_path = list(inference_state.environment.get_sys_path())
         try:
             sys_path.remove('')
         except ValueError:
@@ -94,16 +99,19 @@ class Project(object):
         return sys_path
 
     @inference_state_as_method_param_cache()
-    def _get_sys_path(self, inference_state, environment=None,
-                      add_parent_paths=True, add_init_paths=False):
+    def _get_sys_path(self, inference_state, add_parent_paths=True, add_init_paths=False):
         """
         Keep this method private for all users of jedi. However internally this
         one is used like a public method.
         """
-        suffixed = []
+        suffixed = list(self.added_sys_path)
         prefixed = []
 
-        sys_path = list(self._get_base_sys_path(inference_state, environment))
+        if self._sys_path is None:
+            sys_path = list(self._get_base_sys_path(inference_state))
+        else:
+            sys_path = list(self._sys_path)
+
         if self._smart_sys_path:
             prefixed.append(self._path)
 
@@ -136,16 +144,25 @@ class Project(object):
 
     def save(self):
         data = dict(self.__dict__)
-        for attribute in self._serializer_ignore_attributes:
-            data.pop(attribute, None)
+        data.pop('_environment', None)
+        data.pop('_django', None)  # TODO make django setting public?
+        data = {k.lstrip('_'): v for k, v in data.items()}
 
-        with open(self._get_json_path(self._path), 'wb') as f:
+        # TODO when dropping Python 2 use pathlib.Path.mkdir(parents=True, exist_ok=True)
+        try:
+            os.makedirs(self._get_config_folder_path(self._path))
+        except OSError as e:
+            if e.errno != errno.EEXIST:
+                raise
+        with open(self._get_json_path(self._path), 'w') as f:
             return json.dump((_SERIALIZER_VERSION, data), f)
 
     def get_environment(self):
         if self._environment is None:
-            return get_cached_default_environment()
-
+            if self._python_path is not None:
+                self._environment = create_environment(self._python_path, safe=False)
+            else:
+                self._environment = get_cached_default_environment()
         return self._environment
 
     def __repr__(self):
@@ -192,7 +209,9 @@ def get_default_project(path=None):
                 first_no_init_file = dir
 
         if _is_django_path(dir):
-            return Project(dir, _django=True)
+            project = Project(dir)
+            project._django = True
+            return project
 
         if probable_path is None and _is_potential_project(dir):
             probable_path = dir
diff --git a/jedi/inference/__init__.py b/jedi/inference/__init__.py
index 7606be42..91f05841 100644
--- a/jedi/inference/__init__.py
+++ b/jedi/inference/__init__.py
@@ -142,7 +142,7 @@ class InferenceState(object):
 
     def get_sys_path(self, **kwargs):
         """Convenience function"""
-        return self.project._get_sys_path(self, environment=self.environment, **kwargs)
+        return self.project._get_sys_path(self, **kwargs)
 
     def infer(self, context, name):
         def_ = name.get_definition(import_name_always=True)
diff --git a/jedi/inference/imports.py b/jedi/inference/imports.py
index bbf944ed..a43e19aa 100644
--- a/jedi/inference/imports.py
+++ b/jedi/inference/imports.py
@@ -191,18 +191,19 @@ class Importer(object):
                 import_path = base + tuple(import_path)
             else:
                 path = module_context.py__file__()
+                project_path = self._inference_state.project._path
                 import_path = list(import_path)
                 if path is None:
                     # If no path is defined, our best guess is that the current
                     # file is edited by a user on the current working
                     # directory. We need to add an initial path, because it
                     # will get removed as the name of the current file.
-                    directory = os.getcwd()
+                    directory = project_path
                 else:
                     directory = os.path.dirname(path)
 
                 base_import_path, base_directory = _level_to_base_import_path(
-                    self._inference_state.project._path, directory, level,
+                    project_path, directory, level,
                 )
                 if base_directory is None:
                     # Everything is lost, the relative import does point
@@ -454,8 +455,12 @@ def _load_python_module(inference_state, file_io,
 
 
 def _load_builtin_module(inference_state, import_names=None, sys_path=None):
+    project = inference_state.project
     if sys_path is None:
         sys_path = inference_state.get_sys_path()
+    if not project._load_unsafe_extensions:
+        safe_paths = project._get_base_sys_path(inference_state)
+        sys_path = [p for p in sys_path if p in safe_paths]
 
     dotted_name = '.'.join(import_names)
     assert dotted_name is not None
diff --git a/test/helpers.py b/test/helpers.py
index 7e991915..f2782829 100644
--- a/test/helpers.py
+++ b/test/helpers.py
@@ -16,8 +16,10 @@ import os
 import pytest
 from os.path import abspath, dirname, join
 from functools import partial, wraps
+from jedi import Project
 
 test_dir = dirname(abspath(__file__))
+test_dir_project = Project(test_dir)
 root_dir = dirname(test_dir)
 example_dir = join(test_dir, 'examples')
 
diff --git a/test/test_api/test_api_classes_follow_definition.py b/test/test_api/test_api_classes_follow_definition.py
index 83ed1c95..4bf3f254 100644
--- a/test/test_api/test_api_classes_follow_definition.py
+++ b/test/test_api/test_api_classes_follow_definition.py
@@ -1,7 +1,9 @@
+from os.path import join
 from itertools import chain
+from functools import partial
 
 import jedi
-from ..helpers import cwd_at
+from ..helpers import test_dir
 
 
 def test_import_empty(Script):
@@ -47,8 +49,8 @@ def test_follow_import_incomplete(Script, environment):
     assert alias == ['module']
 
 
-@cwd_at('test/completion/import_tree')
 def test_follow_definition_nested_import(Script):
+    Script = partial(Script, project=jedi.Project(join(test_dir, 'completion', 'import_tree')))
     types = check_follow_definition_types(Script, "import pkg.mod1; pkg")
     assert types == ['module']
 
diff --git a/test/test_api/test_classes.py b/test/test_api/test_classes.py
index 1d8b9ff4..9be2b07d 100644
--- a/test/test_api/test_classes.py
+++ b/test/test_api/test_classes.py
@@ -129,10 +129,11 @@ def test_completion_docstring(Script, jedi_path):
     Jedi should follow imports in certain conditions
     """
     def docstr(src, result):
-        c = Script(src, sys_path=[jedi_path]).complete()[0]
+        c = Script(src, project=project).complete()[0]
         assert c.docstring(raw=True, fast=False) == cleandoc(result)
 
-    c = Script('import jedi\njed', sys_path=[jedi_path]).complete()[0]
+    project = jedi.Project('.', sys_path=[jedi_path])
+    c = Script('import jedi\njed', project=project).complete()[0]
     assert c.docstring(fast=False) == cleandoc(jedi_doc)
 
     docstr('import jedi\njedi.Scr', cleandoc(jedi.Script.__doc__))
diff --git a/test/test_api/test_full_name.py b/test/test_api/test_full_name.py
index 6858b6ca..5944ad72 100644
--- a/test/test_api/test_full_name.py
+++ b/test/test_api/test_full_name.py
@@ -97,9 +97,10 @@ def test_sub_module(Script, jedi_path):
     path.
     """
     sys_path = [jedi_path]
-    defs = Script('from jedi.api import classes; classes', sys_path=sys_path).infer()
+    project = jedi.Project('.', sys_path=sys_path)
+    defs = Script('from jedi.api import classes; classes', project=project).infer()
     assert [d.full_name for d in defs] == ['jedi.api.classes']
-    defs = Script('import jedi.api; jedi.api', sys_path=sys_path).infer()
+    defs = Script('import jedi.api; jedi.api', project=project).infer()
     assert [d.full_name for d in defs] == ['jedi.api']
 
 
diff --git a/test/test_api/test_defined_names.py b/test/test_api/test_names.py
similarity index 86%
rename from test/test_api/test_defined_names.py
rename to test/test_api/test_names.py
index 8b1c731e..d43a29bb 100644
--- a/test/test_api/test_defined_names.py
+++ b/test/test_api/test_names.py
@@ -4,6 +4,8 @@ Tests for `api.names`.
 
 from textwrap import dedent
 
+import pytest
+
 
 def _assert_definition_names(definitions, names):
     assert [d.name for d in definitions] == names
@@ -167,3 +169,23 @@ def test_no_error(get_names):
     assert b.name == 'b'
     assert a20.name == 'a'
     assert a20.goto() == [a20]
+
+
+@pytest.mark.parametrize(
+    'code, index, is_side_effect', [
+        ('x', 0, False),
+        ('x.x', 0, False),
+        ('x.x', 1, False),
+        ('x.x = 3', 0, False),
+        ('x.x = 3', 1, True),
+        ('def x(x): x.x = 3', 1, False),
+        ('def x(x): x.x = 3', 3, True),
+        ('import sys; sys.path', 0, False),
+        ('import sys; sys.path', 1, False),
+        ('import sys; sys.path', 2, False),
+        ('import sys; sys.path = []', 2, True),
+    ]
+)
+def test_is_side_effect(get_names, code, index, is_side_effect):
+    names = get_names(code, references=True, all_scopes=True)
+    assert names[index].is_side_effect() == is_side_effect
diff --git a/test/test_api/test_project.py b/test/test_api/test_project.py
index f8bc8c60..c3d016f3 100644
--- a/test/test_api/test_project.py
+++ b/test/test_api/test_project.py
@@ -2,6 +2,7 @@ import os
 
 from ..helpers import get_example_dir, set_cwd, root_dir
 from jedi import Interpreter
+from jedi.api import Project, get_default_project
 
 
 def test_django_default_project(Script):
@@ -22,3 +23,18 @@ def test_interpreter_project_path():
     with set_cwd(dir):
         project = Interpreter('', [locals()])._inference_state.project
         assert project._path == dir
+
+
+def test_added_sys_path(inference_state):
+    project = get_default_project()
+    p = '/some_random_path'
+    project.added_sys_path = [p]
+    assert p in project._get_sys_path(inference_state)
+
+
+def test_load_save_project(tmpdir):
+    project = Project(tmpdir.strpath, added_sys_path=['/foo'])
+    project.save()
+
+    loaded = Project.load(tmpdir.strpath)
+    assert loaded.added_sys_path == ['/foo']
diff --git a/test/test_api/test_settings.py b/test/test_api/test_settings.py
index 7a9d0c2c..3a21fc76 100644
--- a/test/test_api/test_settings.py
+++ b/test/test_api/test_settings.py
@@ -4,11 +4,9 @@ import pytest
 
 from jedi import api
 from jedi.inference import imports
-from ..helpers import cwd_at
 
 
 @pytest.mark.skipif('True', reason='Skip for now, test case is not really supported.')
-@cwd_at('jedi')
 def test_add_dynamic_mods(Script):
     fname = '__main__.py'
     api.settings.additional_dynamic_modules = [fname]
diff --git a/test/test_api/test_syntax_errors.py b/test/test_api/test_syntax_errors.py
new file mode 100644
index 00000000..01e99688
--- /dev/null
+++ b/test/test_api/test_syntax_errors.py
@@ -0,0 +1,54 @@
+"""
+These tests test Jedi's Parso usage. Basically there's not a lot of tests here,
+because we're just checking if the API works. Bugfixes should be done in parso,
+mostly.
+"""
+
+from textwrap import dedent
+
+import pytest
+
+
+@pytest.mark.parametrize(
+    'code, line, column, until_line, until_column', [
+        ('?\n', 1, 0, 1, 1),
+        ('x %% y', 1, 3, 1, 4),
+        ('"""\n\n', 1, 0, 3, 0),
+        ('(1, 2\n', 2, 0, 2, 0),
+        ('foo(1, 2\ndef x(): pass', 2, 0, 2, 3),
+    ]
+)
+def test_simple_syntax_errors(Script, code, line, column, until_line, until_column):
+    e, = Script(code).get_syntax_errors()
+    assert e.line == line
+    assert e.column == column
+    assert e.until_line == until_line
+    assert e.until_column == until_column
+
+
+@pytest.mark.parametrize(
+    'code', [
+        'x % y',
+        'def x(x): pass',
+        'def x(x):\n pass',
+    ]
+)
+def test_no_syntax_errors(Script, code):
+    assert not Script(code).get_syntax_errors()
+
+
+def test_multi_syntax_error(Script):
+    code = dedent('''\
+        def x():
+        1
+        def y()
+        1 + 1
+        1 *** 3
+        ''')
+    x, y, power = Script(code).get_syntax_errors()
+    assert x.line == 2
+    assert x.column == 0
+    assert y.line == 3
+    assert y.column == 7
+    assert power.line == 5
+    assert power.column == 4
diff --git a/test/test_api/test_unicode.py b/test/test_api/test_unicode.py
index 015048cd..f7f7ec45 100644
--- a/test/test_api/test_unicode.py
+++ b/test/test_api/test_unicode.py
@@ -3,6 +3,7 @@
 All character set and unicode related tests.
 """
 from jedi._compatibility import u, unicode
+from jedi import Project
 
 
 def test_unicode_script(Script):
@@ -70,7 +71,8 @@ def test_wrong_encoding(Script, tmpdir):
     # Use both latin-1 and utf-8 (a really broken file).
     x.write_binary(u'foobar = 1\nä'.encode('latin-1') + u'ä'.encode('utf-8'))
 
-    c, = Script('import x; x.foo', sys_path=[tmpdir.strpath]).complete()
+    project = Project('.', sys_path=[tmpdir.strpath])
+    c, = Script('import x; x.foo', project=project).complete()
     assert c.name == 'foobar'
 
 
diff --git a/test/test_api/test_usages.py b/test/test_api/test_usages.py
index 4d0effdc..188f893d 100644
--- a/test/test_api/test_usages.py
+++ b/test/test_api/test_usages.py
@@ -6,7 +6,7 @@ def test_import_references(Script):
 def test_exclude_builtin_modules(Script):
     def get(include):
         from jedi.api.project import Project
-        script = Script(source, _project=Project('', sys_path=[], smart_sys_path=False))
+        script = Script(source, project=Project('', sys_path=[], smart_sys_path=False))
         references = script.get_references(column=8, include_builtins=include)
         return [(d.line, d.column) for d in references]
     source = '''import sys\nprint(sys.path)'''
diff --git a/test/test_inference/test_absolute_import.py b/test/test_inference/test_absolute_import.py
index 3bf9dd2e..72017dc9 100644
--- a/test/test_inference/test_absolute_import.py
+++ b/test/test_inference/test_absolute_import.py
@@ -2,10 +2,11 @@
 Tests ``from __future__ import absolute_import`` (only important for
 Python 2.X)
 """
+from jedi import Project
 from .. import helpers
 
 
-@helpers.cwd_at("test/examples/absolute_import")
 def test_can_complete_when_shadowing(Script):
-    script = Script(path="unittest.py")
+    path = helpers.get_example_dir('absolute_import', 'unittest.py')
+    script = Script(path=path, project=Project(helpers.get_example_dir('absolute_import')))
     assert script.complete()
diff --git a/test/test_inference/test_buildout_detection.py b/test/test_inference/test_buildout_detection.py
index 6815aa9b..aa70eca0 100644
--- a/test/test_inference/test_buildout_detection.py
+++ b/test/test_inference/test_buildout_detection.py
@@ -5,7 +5,7 @@ from jedi._compatibility import force_unicode
 from jedi.inference.sys_path import _get_parent_dir_with_file, \
     _get_buildout_script_paths, check_sys_path_modifications
 
-from ..helpers import cwd_at
+from ..helpers import get_example_dir
 
 
 def check_module_test(Script, code):
@@ -13,20 +13,18 @@ def check_module_test(Script, code):
     return check_sys_path_modifications(module_context)
 
 
-@cwd_at('test/examples/buildout_project/src/proj_name')
 def test_parent_dir_with_file(Script):
-    parent = _get_parent_dir_with_file(
-        os.path.abspath(os.curdir), 'buildout.cfg')
+    path = get_example_dir('buildout_project', 'src', 'proj_name')
+    parent = _get_parent_dir_with_file(path, 'buildout.cfg')
     assert parent is not None
     assert parent.endswith(os.path.join('test', 'examples', 'buildout_project'))
 
 
-@cwd_at('test/examples/buildout_project/src/proj_name')
 def test_buildout_detection(Script):
-    scripts = list(_get_buildout_script_paths(os.path.abspath('./module_name.py')))
+    path = get_example_dir('buildout_project', 'src', 'proj_name')
+    scripts = list(_get_buildout_script_paths(os.path.join(path, 'module_name.py')))
     assert len(scripts) == 1
-    curdir = os.path.abspath(os.curdir)
-    appdir_path = os.path.normpath(os.path.join(curdir, '../../bin/app'))
+    appdir_path = os.path.normpath(os.path.join(path, '../../bin/app'))
     assert scripts[0] == appdir_path
 
 
@@ -53,13 +51,12 @@ def test_path_from_invalid_sys_path_assignment(Script):
     assert 'invalid' not in paths
 
 
-@cwd_at('test/examples/buildout_project/src/proj_name/')
 def test_sys_path_with_modifications(Script):
+    path = get_example_dir('buildout_project', 'src', 'proj_name', 'module_name.py')
     code = dedent("""
         import os
     """)
 
-    path = os.path.abspath(os.path.join(os.curdir, 'module_name.py'))
     paths = Script(code, path=path)._inference_state.get_sys_path()
     assert '/tmp/.buildout/eggs/important_package.egg' in paths
 
diff --git a/test/test_inference/test_extension.py b/test/test_inference/test_extension.py
index 6e6f5899..a63af388 100644
--- a/test/test_inference/test_extension.py
+++ b/test/test_inference/test_extension.py
@@ -4,7 +4,7 @@ Test compiled module
 import os
 
 import jedi
-from ..helpers import cwd_at
+from ..helpers import get_example_dir
 import pytest
 
 
@@ -34,9 +34,9 @@ def test_get_signatures_stdlib(Script):
 
 
 # Check only on linux 64 bit platform and Python3.4.
+@pytest.mark.parametrize('load_unsafe_extensions', [False, True])
 @pytest.mark.skipif('sys.platform != "linux" or sys.maxsize <= 2**32 or sys.version_info[:2] != (3, 4)')
-@cwd_at('test/examples')
-def test_init_extension_module(Script):
+def test_init_extension_module(Script, load_unsafe_extensions):
     """
     ``__init__`` extension modules are also packages and Jedi should understand
     that.
@@ -50,8 +50,26 @@ def test_init_extension_module(Script):
 
     This is also why this test only runs on certain systems (and Python 3.4).
     """
-    s = jedi.Script('import init_extension_module as i\ni.', path='not_existing.py')
-    assert 'foo' in [c.name for c in s.complete()]
 
-    s = jedi.Script('from init_extension_module import foo\nfoo', path='not_existing.py')
-    assert ['foo'] == [c.name for c in s.complete()]
+    project = jedi.Project(get_example_dir(), load_unsafe_extensions=load_unsafe_extensions)
+    s = jedi.Script(
+        'import init_extension_module as i\ni.',
+        path='not_existing.py',
+        project=project,
+    )
+    if load_unsafe_extensions:
+        assert 'foo' in [c.name for c in s.complete()]
+    else:
+        assert 'foo' not in [c.name for c in s.complete()]
+
+    s = jedi.Script(
+        'from init_extension_module import foo\nfoo',
+        path='not_existing.py',
+        project=project,
+    )
+    c, = s.complete()
+    assert c.name == 'foo'
+    if load_unsafe_extensions:
+        assert c.infer()
+    else:
+        assert not c.infer()
diff --git a/test/test_inference/test_gradual/test_conversion.py b/test/test_inference/test_gradual/test_conversion.py
index b63129ae..fd05d265 100644
--- a/test/test_inference/test_gradual/test_conversion.py
+++ b/test/test_inference/test_gradual/test_conversion.py
@@ -28,10 +28,10 @@ def test_sqlite3_conversion(Script):
 def test_conversion_of_stub_only(Script):
     project = Project(os.path.join(root_dir, 'test', 'completion', 'stub_folder'))
     code = 'import stub_only; stub_only.in_stub_only'
-    d1, = Script(code, _project=project).goto()
+    d1, = Script(code, project=project).goto()
     assert d1.is_stub()
 
-    script = Script(path=d1.module_path, _project=project)
+    script = Script(path=d1.module_path, project=project)
     d2, = script.goto(line=d1.line, column=d1.column)
     assert d2.is_stub()
     assert d2.module_path == d1.module_path
@@ -42,7 +42,7 @@ def test_conversion_of_stub_only(Script):
 
 def test_goto_on_file(Script):
     project = Project(os.path.join(root_dir, 'test', 'completion', 'stub_folder'))
-    script = Script('import stub_only; stub_only.Foo', _project=project)
+    script = Script('import stub_only; stub_only.Foo', project=project)
     d1, = script.goto()
     v, = d1._name.infer()
     foo, bar, obj = v.py__mro__()
@@ -51,7 +51,7 @@ def test_goto_on_file(Script):
     assert obj.py__name__() == 'object'
 
     # Make sure we go to Bar, because Foo is a bit before: `class Foo(Bar):`
-    script = Script(path=d1.module_path, _project=project)
+    script = Script(path=d1.module_path, project=project)
     d2, = script.goto(line=d1.line, column=d1.column + 4)
     assert d2.name == 'Bar'
 
diff --git a/test/test_inference/test_gradual/test_stub_loading.py b/test/test_inference/test_gradual/test_stub_loading.py
index 7d62a24c..ab64f00c 100644
--- a/test/test_inference/test_gradual/test_stub_loading.py
+++ b/test/test_inference/test_gradual/test_stub_loading.py
@@ -9,7 +9,7 @@ import pytest
 def ScriptInStubFolder(Script):
     path = get_example_dir('stub_packages')
     project = Project(path, sys_path=[path], smart_sys_path=False)
-    return partial(Script, _project=project)
+    return partial(Script, project=project)
 
 
 @pytest.mark.parametrize(
diff --git a/test/test_inference/test_gradual/test_stubs.py b/test/test_inference/test_gradual/test_stubs.py
index 8d7bdb02..1d82dd0b 100644
--- a/test/test_inference/test_gradual/test_stubs.py
+++ b/test/test_inference/test_gradual/test_stubs.py
@@ -54,7 +54,7 @@ def test_infer_and_goto(Script, code, full_name, has_stub, has_python, way,
         has_python = False
 
     project = Project(os.path.join(root_dir, 'test', 'completion', 'stub_folder'))
-    s = Script(code, _project=project)
+    s = Script(code, project=project)
     prefer_stubs = kwargs['prefer_stubs']
     only_stubs = kwargs['only_stubs']
 
diff --git a/test/test_inference/test_implicit_namespace_package.py b/test/test_inference/test_implicit_namespace_package.py
index 2df9de0c..0b3bee71 100644
--- a/test/test_inference/test_implicit_namespace_package.py
+++ b/test/test_inference/test_implicit_namespace_package.py
@@ -3,6 +3,7 @@ from os.path import dirname
 import pytest
 
 from test.helpers import get_example_dir, example_dir
+from jedi import Project
 
 
 @pytest.fixture(autouse=True)
@@ -14,9 +15,10 @@ def skip_not_supported_versions(environment):
 def test_implicit_namespace_package(Script):
     sys_path = [get_example_dir('implicit_namespace_package', 'ns1'),
                 get_example_dir('implicit_namespace_package', 'ns2')]
+    project = Project('.', sys_path=sys_path)
 
     def script_with_path(*args, **kwargs):
-        return Script(sys_path=sys_path, *args, **kwargs)
+        return Script(project=project, *args, **kwargs)
 
     # goto definition
     assert script_with_path('from pkg import ns1_file').infer()
@@ -55,15 +57,14 @@ def test_implicit_namespace_package(Script):
 def test_implicit_nested_namespace_package(Script):
     code = 'from implicit_nested_namespaces.namespace.pkg.module import CONST'
 
-    sys_path = [example_dir]
-
-    script = Script(sys_path=sys_path, source=code, line=1, column=61)
+    project = Project('.', sys_path=[example_dir])
+    script = Script(project=project, source=code, line=1, column=61)
 
     result = script.infer()
 
     assert len(result) == 1
 
-    implicit_pkg, = Script(code, sys_path=sys_path).infer(column=10)
+    implicit_pkg, = Script(code, project=project).infer(column=10)
     assert implicit_pkg.type == 'module'
     assert implicit_pkg.module_path is None
 
@@ -71,9 +72,8 @@ def test_implicit_nested_namespace_package(Script):
 def test_implicit_namespace_package_import_autocomplete(Script):
     CODE = 'from implicit_name'
 
-    sys_path = [example_dir]
-
-    script = Script(sys_path=sys_path, source=CODE)
+    project = Project('.', sys_path=[example_dir])
+    script = Script(project=project, source=CODE)
     compl = script.complete()
     assert [c.name for c in compl] == ['implicit_namespace_package']
 
@@ -83,7 +83,8 @@ def test_namespace_package_in_multiple_directories_autocompletion(Script):
     sys_path = [get_example_dir('implicit_namespace_package', 'ns1'),
                 get_example_dir('implicit_namespace_package', 'ns2')]
 
-    script = Script(sys_path=sys_path, source=CODE)
+    project = Project('.', sys_path=sys_path)
+    script = Script(project=project, source=CODE)
     compl = script.complete()
     assert set(c.name for c in compl) == set(['ns1_file', 'ns2_file'])
 
@@ -92,7 +93,8 @@ def test_namespace_package_in_multiple_directories_goto_definition(Script):
     CODE = 'from pkg import ns1_file'
     sys_path = [get_example_dir('implicit_namespace_package', 'ns1'),
                 get_example_dir('implicit_namespace_package', 'ns2')]
-    script = Script(sys_path=sys_path, source=CODE)
+    project = Project('.', sys_path=sys_path)
+    script = Script(project=project, source=CODE)
     result = script.infer()
     assert len(result) == 1
 
@@ -102,6 +104,7 @@ def test_namespace_name_autocompletion_full_name(Script):
     sys_path = [get_example_dir('implicit_namespace_package', 'ns1'),
                 get_example_dir('implicit_namespace_package', 'ns2')]
 
-    script = Script(sys_path=sys_path, source=CODE)
+    project = Project('.', sys_path=sys_path)
+    script = Script(project=project, source=CODE)
     compl = script.complete()
     assert set(c.full_name for c in compl) == set(['pkg'])
diff --git a/test/test_inference/test_imports.py b/test/test_inference/test_imports.py
index 9ec393ed..77b07be1 100644
--- a/test/test_inference/test_imports.py
+++ b/test/test_inference/test_imports.py
@@ -6,15 +6,15 @@ Tests".
 import os
 
 import pytest
-from jedi.file_io import FileIO, KnownContentFileIO
 
+from jedi.file_io import FileIO, KnownContentFileIO
 from jedi._compatibility import find_module_py33, find_module
 from jedi.inference import compiled
 from jedi.inference import imports
 from jedi.api.project import Project
 from jedi.inference.gradual.conversion import _stub_to_python_value_set
 from jedi.inference.references import get_module_contexts_containing_name
-from ..helpers import cwd_at, get_example_dir, test_dir, root_dir
+from ..helpers import get_example_dir, test_dir, test_dir_project, root_dir
 
 THIS_DIR = os.path.dirname(__file__)
 
@@ -44,7 +44,9 @@ pkg_zip_path = get_example_dir('zipped_imports', 'pkg.zip')
 
 def test_find_module_package_zipped(Script, inference_state, environment):
     sys_path = environment.get_sys_path() + [pkg_zip_path]
-    script = Script('import pkg; pkg.mod', sys_path=sys_path)
+
+    project = Project('.', sys_path=sys_path)
+    script = Script('import pkg; pkg.mod', project=project)
     assert len(script.complete()) == 1
 
     file_io, is_package = inference_state.compiled_subprocess.get_module_info(
@@ -86,7 +88,7 @@ def test_find_module_package_zipped(Script, inference_state, environment):
 def test_correct_zip_package_behavior(Script, inference_state, environment, code,
                                       file, package, path, skip_python2):
     sys_path = environment.get_sys_path() + [pkg_zip_path]
-    pkg, = Script(code, sys_path=sys_path).infer()
+    pkg, = Script(code, project=Project('.', sys_path=sys_path)).infer()
     value, = pkg._name.infer()
     assert value.py__file__() == os.path.join(pkg_zip_path, 'pkg', file)
     assert '.'.join(value.py__package__()) == package
@@ -98,7 +100,7 @@ def test_correct_zip_package_behavior(Script, inference_state, environment, code
 def test_find_module_not_package_zipped(Script, inference_state, environment):
     path = get_example_dir('zipped_imports', 'not_pkg.zip')
     sys_path = environment.get_sys_path() + [path]
-    script = Script('import not_pkg; not_pkg.val', sys_path=sys_path)
+    script = Script('import not_pkg; not_pkg.val', project=Project('.', sys_path=sys_path))
     assert len(script.complete()) == 1
 
     file_io, is_package = inference_state.compiled_subprocess.get_module_info(
@@ -110,19 +112,24 @@ def test_find_module_not_package_zipped(Script, inference_state, environment):
     assert is_package is False
 
 
-@cwd_at('test/examples/not_in_sys_path/pkg')
-def test_import_not_in_sys_path(Script):
+def test_import_not_in_sys_path(Script, environment):
     """
     non-direct imports (not in sys.path)
 
     This is in the end just a fallback.
     """
-    a = Script(path='module.py').infer(line=5)
+    path = get_example_dir()
+    module_path = os.path.join(path, 'not_in_sys_path', 'pkg', 'module.py')
+    # This project tests the smart path option of Project. The sys_path is
+    # explicitly given to make sure that the path is just dumb and only
+    # includes non-folder dependencies.
+    project = Project(path, sys_path=environment.get_sys_path())
+    a = Script(path=module_path, project=project).infer(line=5)
     assert a[0].name == 'int'
 
-    a = Script(path='module.py').infer(line=6)
+    a = Script(path=module_path, project=project).infer(line=6)
     assert a[0].name == 'str'
-    a = Script(path='module.py').infer(line=7)
+    a = Script(path=module_path, project=project).infer(line=7)
     assert a[0].name == 'str'
 
 
@@ -144,14 +151,13 @@ def test_flask_ext(Script, code, name):
     """flask.ext.foo is really imported from flaskext.foo or flask_foo.
     """
     path = get_example_dir('flask-site-packages')
-    completions = Script(code, sys_path=[path]).complete()
+    completions = Script(code, project=Project('.', sys_path=[path])).complete()
     assert name in [c.name for c in completions]
 
 
-@cwd_at('test/test_inference/')
 def test_not_importable_file(Script):
     src = 'import not_importable_file as x; x.'
-    assert not Script(src, path='example.py').complete()
+    assert not Script(src, path='example.py', project=test_dir_project).complete()
 
 
 def test_import_unique(Script):
@@ -166,10 +172,14 @@ def test_cache_works_with_sys_path_param(Script, tmpdir):
     bar_path = tmpdir.join('bar')
     foo_path.join('module.py').write('foo = 123', ensure=True)
     bar_path.join('module.py').write('bar = 123', ensure=True)
-    foo_completions = Script('import module; module.',
-                             sys_path=[foo_path.strpath]).complete()
-    bar_completions = Script('import module; module.',
-                             sys_path=[bar_path.strpath]).complete()
+    foo_completions = Script(
+        'import module; module.',
+        project=Project('.', sys_path=[foo_path.strpath]),
+    ).complete()
+    bar_completions = Script(
+        'import module; module.',
+        project=Project('.', sys_path=[bar_path.strpath]),
+    ).complete()
     assert 'foo' in [c.name for c in foo_completions]
     assert 'bar' not in [c.name for c in foo_completions]
 
@@ -194,29 +204,29 @@ def test_goto_definition_on_import(Script):
     assert len(Script("import sys").infer(1, 8)) == 1
 
 
-@cwd_at('jedi')
-def test_complete_on_empty_import(Script):
-    assert Script("from datetime import").complete()[0].name == 'import'
+def test_complete_on_empty_import(ScriptWithProject):
+    path = os.path.join(test_dir, 'whatever.py')
+    assert ScriptWithProject("from datetime import").complete()[0].name == 'import'
     # should just list the files in the directory
-    assert 10 < len(Script("from .", path='whatever.py').complete()) < 30
+    assert 10 < len(ScriptWithProject("from .", path=path).complete()) < 30
 
     # Global import
-    assert len(Script("from . import", 'whatever.py').complete(1, 5)) > 30
+    assert len(ScriptWithProject("from . import", path=path).complete(1, 5)) > 30
     # relative import
-    assert 10 < len(Script("from . import", 'whatever.py').complete(1, 6)) < 30
+    assert 10 < len(ScriptWithProject("from . import", path=path).complete(1, 6)) < 30
 
     # Global import
-    assert len(Script("from . import classes", 'whatever.py').complete(1, 5)) > 30
+    assert len(ScriptWithProject("from . import classes", path=path).complete(1, 5)) > 30
     # relative import
-    assert 10 < len(Script("from . import classes", 'whatever.py').complete(1, 6)) < 30
+    assert 10 < len(ScriptWithProject("from . import classes", path=path).complete(1, 6)) < 30
 
     wanted = {'ImportError', 'import', 'ImportWarning'}
-    assert {c.name for c in Script("import").complete()} == wanted
-    assert len(Script("import import", path='').complete()) > 0
+    assert {c.name for c in ScriptWithProject("import").complete()} == wanted
+    assert len(ScriptWithProject("import import", path=path).complete()) > 0
 
     # 111
-    assert Script("from datetime import").complete()[0].name == 'import'
-    assert Script("from datetime import ").complete()
+    assert ScriptWithProject("from datetime import").complete()[0].name == 'import'
+    assert ScriptWithProject("from datetime import ").complete()
 
 
 def test_imports_on_global_namespace_without_path(Script):
@@ -363,7 +373,7 @@ def test_relative_imports_with_multiple_similar_directories(Script, path, empty_
     script = Script(
         "from . ",
         path=os.path.join(dir, path),
-        _project=project,
+        project=project,
     )
     name, import_ = script.complete()
     assert import_.name == 'import'
@@ -376,28 +386,28 @@ def test_relative_imports_with_outside_paths(Script):
     script = Script(
         "from ...",
         path=os.path.join(dir, 'api/whatever/test_this.py'),
-        _project=project,
+        project=project,
     )
     assert [c.name for c in script.complete()] == ['api', 'whatever']
 
     script = Script(
         "from " + '.' * 100,
         path=os.path.join(dir, 'api/whatever/test_this.py'),
-        _project=project,
+        project=project,
     )
     assert not script.complete()
 
 
-@cwd_at('test/examples/issue1209/api/whatever/')
 def test_relative_imports_without_path(Script):
-    project = Project('.', sys_path=[], smart_sys_path=False)
-    script = Script("from . ", _project=project)
+    path = get_example_dir('issue1209', 'api', 'whatever')
+    project = Project(path, sys_path=[], smart_sys_path=False)
+    script = Script("from . ", project=project)
     assert [c.name for c in script.complete()] == ['api_test1', 'import']
 
-    script = Script("from .. ", _project=project)
+    script = Script("from .. ", project=project)
     assert [c.name for c in script.complete()] == ['import', 'whatever']
 
-    script = Script("from ... ", _project=project)
+    script = Script("from ... ", project=project)
     assert [c.name for c in script.complete()] == ['api', 'import', 'whatever']
 
 
@@ -460,7 +470,7 @@ def test_import_needed_modules_by_jedi(Script, environment, tmpdir, name):
     script = Script(
         'import ' + name,
         path=tmpdir.join('something.py').strpath,
-        sys_path=[tmpdir.strpath] + environment.get_sys_path(),
+        project=Project('.', sys_path=[tmpdir.strpath] + environment.get_sys_path()),
     )
     module, = script.infer()
     assert module._inference_state.builtins_module.py__file__() != module_path
diff --git a/test/test_inference/test_namespace_package.py b/test/test_inference/test_namespace_package.py
index f6b34151..0867af85 100644
--- a/test/test_inference/test_namespace_package.py
+++ b/test/test_inference/test_namespace_package.py
@@ -4,6 +4,7 @@ import pytest
 import py
 
 from ..helpers import get_example_dir, example_dir
+from jedi import Project
 
 
 SYS_PATH = [get_example_dir('namespace_package', 'ns1'),
@@ -11,7 +12,7 @@ SYS_PATH = [get_example_dir('namespace_package', 'ns1'),
 
 
 def script_with_path(Script, *args, **kwargs):
-    return Script(sys_path=SYS_PATH, *args, **kwargs)
+    return Script(project=Project('.', sys_path=SYS_PATH), *args, **kwargs)
 
 
 def test_goto_definition(Script):
@@ -69,8 +70,8 @@ def test_nested_namespace_package(Script):
     code = 'from nested_namespaces.namespace.pkg import CONST'
 
     sys_path = [example_dir]
-
-    script = Script(sys_path=sys_path, source=code)
+    project = Project('.', sys_path=sys_path)
+    script = Script(project=project, source=code)
 
     result = script.infer(line=1, column=45)
 
diff --git a/test/test_inference/test_pyc.py b/test/test_inference/test_pyc.py
index 615fd1cd..35d51327 100644
--- a/test/test_inference/test_pyc.py
+++ b/test/test_inference/test_pyc.py
@@ -55,7 +55,8 @@ def pyc_project_path(tmpdir):
         shutil.rmtree(path)
 
 
-def test_pyc(pyc_project_path, environment):
+@pytest.mark.parametrize('load_unsafe_extensions', [False, True])
+def test_pyc(pyc_project_path, environment, load_unsafe_extensions):
     """
     The list of completion must be greater than 2.
     """
@@ -66,8 +67,14 @@ def test_pyc(pyc_project_path, environment):
         # we also have the same version and it's easier to debug.
         environment = SameEnvironment()
     environment = environment
+    project = jedi.Project(pyc_project_path, load_unsafe_extensions=load_unsafe_extensions)
     s = jedi.Script(
         "from dummy_package import dummy; dummy.",
         path=path,
-        environment=environment)
-    assert len(s.complete()) >= 2
+        environment=environment,
+        project=project,
+    )
+    if load_unsafe_extensions:
+        assert len(s.complete()) >= 2
+    else:
+        assert not s.complete()
diff --git a/test/test_speed.py b/test/test_speed.py
index f08f0644..ea37a154 100644
--- a/test/test_speed.py
+++ b/test/test_speed.py
@@ -6,7 +6,7 @@ should.
 import time
 import functools
 
-from .helpers import cwd_at, get_example_dir
+from .helpers import get_example_dir
 import jedi
 
 
@@ -44,7 +44,6 @@ def test_scipy_speed(Script):
 
 
 @_check_speed(0.8)
-@cwd_at('test')
 def test_precedence_slowdown(Script):
     """
     Precedence calculation can slow down things significantly in edge
diff --git a/test/test_utils.py b/test/test_utils.py
index a4c510e0..e91eb62d 100644
--- a/test/test_utils.py
+++ b/test/test_utils.py
@@ -5,7 +5,7 @@ except ImportError:
 
 from jedi import utils
 
-from .helpers import unittest, cwd_at
+from .helpers import unittest
 
 
 @unittest.skipIf(not readline, "readline not found")
@@ -86,9 +86,8 @@ class TestSetupReadline(unittest.TestCase):
         # (posix and nt) librariesare included.
         assert len(difference) < 20
 
-    @cwd_at('test')
     def test_local_import(self):
-        s = 'import test_utils'
+        s = 'import test.test_utils'
         assert self.complete(s) == [s]
 
     def test_preexisting_values(self):