diff --git a/jedi/evaluate.py b/jedi/evaluate.py
index 551852d7..c76bbb27 100644
--- a/jedi/evaluate.py
+++ b/jedi/evaluate.py
@@ -68,11 +68,11 @@ backtracking algorithm.
 
 .. todo:: nonlocal statement, needed or can be ignored? (py3k)
 """
-from _compatibility import next, hasattr, is_py3k, unicode, reraise
 
 import sys
 import itertools
 
+from jedi._compatibility import next, hasattr, is_py3k, unicode, reraise
 from jedi import common
 from jedi import cache
 from jedi import parsing_representation as pr
diff --git a/jedi/evaluate_representation.py b/jedi/evaluate_representation.py
index 99fded99..f5c6e991 100644
--- a/jedi/evaluate_representation.py
+++ b/jedi/evaluate_representation.py
@@ -12,7 +12,7 @@ they change classes in Python 3.
 import copy
 import itertools
 
-from _compatibility import property, use_metaclass, next, hasattr
+from jedi._compatibility import property, use_metaclass, next, hasattr
 from jedi import parsing_representation as pr
 from jedi import cache
 from jedi import helpers
diff --git a/jedi/keywords.py b/jedi/keywords.py
index 07461bb7..5495ae32 100644
--- a/jedi/keywords.py
+++ b/jedi/keywords.py
@@ -2,7 +2,7 @@ import pydoc
 import keyword
 
 from jedi._compatibility import is_py3k
-from jedi import builtin
+import builtin
 
 try:
     from pydoc_data import topics as pydoc_topics
diff --git a/jedi/modules.py b/jedi/modules.py
index b6c8f1e8..9277e742 100644
--- a/jedi/modules.py
+++ b/jedi/modules.py
@@ -15,13 +15,12 @@ Apart from those classes there's a ``sys.path`` fetching function, as well as
 """
 from __future__ import with_statement
 
-from _compatibility import exec_function, unicode, is_py25, literal_eval
-
 import re
 import tokenize
 import sys
 import os
 
+from jedi._compatibility import exec_function, unicode, is_py25, literal_eval
 from jedi import cache
 from jedi import parsing
 from jedi import parsing_representation as pr
diff --git a/jedi/parsing.py b/jedi/parsing.py
index 17ca7d49..69607fec 100644
--- a/jedi/parsing.py
+++ b/jedi/parsing.py
@@ -15,11 +15,11 @@ within the statement. This lowers memory usage and cpu time and reduces the
 complexity of the ``Parser`` (there's another parser sitting inside
 ``Statement``, which produces ``Array`` and ``Call``).
 """
-from _compatibility import next, StringIO
 
 import tokenize
 import keyword
 
+from jedi._compatibility import next, StringIO
 from jedi import debug
 from jedi import common
 from jedi import parsing_representation as pr
diff --git a/test/test_regression.py b/test/test_regression.py
index 6ed6a9f9..3952e6b7 100755
--- a/test/test_regression.py
+++ b/test/test_regression.py
@@ -16,7 +16,7 @@ from .base import TestBase, unittest, cwd_at
 import jedi
 from jedi._compatibility import is_py25, utf8, unicode
 from jedi import api
-from jedi import api_classes
+api_classes = api.api_classes
 
 #jedi.set_debug_function(jedi.debug.print_to_stdout)
 
@@ -534,5 +534,45 @@ def test_settings_module():
     assert cache.settings is settings
 
 
+def test_no_duplicate_modules():
+    """
+    Make sure that import hack works as expected.
+
+    Jedi does an import hack (see: jedi/__init__.py) to have submodules
+    with circular dependencies.  The modules in this circular dependency
+    "loop" must be imported by ``import <module>`` rather than normal
+    ``from jedi import <module>`` (or ``from . jedi ...``).  This test
+    make sure that this is satisfied.
+
+    See also:
+
+    - `#160 <https://github.com/davidhalter/jedi/issues/160>`_
+    - `#161 <https://github.com/davidhalter/jedi/issues/161>`_
+    """
+    import sys
+    jedipath = os.path.dirname(os.path.abspath(jedi.__file__))
+
+    def is_submodule(m):
+        try:
+            filepath = m.__file__
+        except AttributeError:
+            return False
+        return os.path.abspath(filepath).startswith(jedipath)
+
+    modules = list(filter(is_submodule, sys.modules.values()))
+    top_modules = [m for m in modules if not m.__name__.startswith('jedi.')]
+    for m in modules:
+        if m is jedi:
+            # py.test automatically improts `jedi.*` when --doctest-modules
+            # is given.  So this test cannot succeeds.
+            continue
+        for tm in top_modules:
+            try:
+                imported = getattr(m, tm.__name__)
+            except AttributeError:
+                continue
+            assert imported is tm
+
+
 if __name__ == '__main__':
     unittest.main()