diff --git a/gns3server/handlers/__init__.py b/gns3server/handlers/__init__.py
index c2247f30..464fa4a8 100644
--- a/gns3server/handlers/__init__.py
+++ b/gns3server/handlers/__init__.py
@@ -15,6 +15,8 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import sys
+import os
+
 from gns3server.handlers.api.version_handler import VersionHandler
 from gns3server.handlers.api.network_handler import NetworkHandler
 from gns3server.handlers.api.project_handler import ProjectHandler
@@ -25,5 +27,6 @@ from gns3server.handlers.api.virtualbox_handler import VirtualBoxHandler
 from gns3server.handlers.api.vpcs_handler import VPCSHandler
 from gns3server.handlers.upload_handler import UploadHandler
 
-if sys.platform.startswith("linux"):
+print(os.environ)
+if sys.platform.startswith("linux") or hasattr(sys, "_called_from_test"):
     from gns3server.handlers.api.iou_handler import IOUHandler
diff --git a/gns3server/modules/__init__.py b/gns3server/modules/__init__.py
index 6b679996..4dce8ccc 100644
--- a/gns3server/modules/__init__.py
+++ b/gns3server/modules/__init__.py
@@ -23,7 +23,7 @@ from .qemu import Qemu
 
 MODULES = [VPCS, VirtualBox, Dynamips, Qemu]
 
-if sys.platform.startswith("linux"):
+if sys.platform.startswith("linux") or hasattr(sys, "_called_from_test"):
     # IOU runs only on Linux
     from .iou import IOU
     MODULES.append(IOU)
diff --git a/tests/conftest.py b/tests/conftest.py
index e9448aaf..b4599ce2 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -15,14 +15,20 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+
 import pytest
 import socket
 import asyncio
 import tempfile
 import shutil
 import os
+import sys
 from aiohttp import web
 
+sys._called_from_test = True
+# Prevent execution of external binaries
+os.environ["PATH"] = tempfile.mkdtemp()
+
 from gns3server.config import Config
 from gns3server.web.route import Route
 # TODO: get rid of *
@@ -33,10 +39,6 @@ from gns3server.modules.project_manager import ProjectManager
 from tests.handlers.api.base import Query
 
 
-# Prevent execution of external binaries
-os.environ["PATH"] = tempfile.mkdtemp()
-
-
 @pytest.yield_fixture
 def restore_original_path():
     """