It's was hard but i have finally a beginning of test for start VPCS

tests/modules/vpcs/test_vpcs_device.py

@@ -16,7 +16,13 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import pytest
-from unittest.mock import patch
+import asyncio
+from tests.utils import asyncio_patch
+
+#Move loop to util
+from tests.api.base import loop
+from asyncio.subprocess import Process
+from unittest.mock import patch, Mock
 from gns3server.modules.vpcs.vpcs_device import VPCSDevice
 from gns3server.modules.vpcs.vpcs_error import VPCSError
 
@@ -39,3 +45,9 @@ def test_vm_invalid_vpcs_path(tmpdir):
         assert vm.name == "test"
         assert vm.id == 42
 
+def test_start(tmpdir, loop):
+    with asyncio_patch("asyncio.create_subprocess_exec", return_value=Mock()):
+        vm = VPCSDevice("test", 42, working_dir=str(tmpdir), path="/bin/test_fake")
+        loop.run_until_complete(asyncio.async(vm.start()))
+        assert vm.is_running() == True
+