WIP split _create_vm out of create_vms fixture

Will help implementing vm import as alternative to creation

conftest.py

@@ -503,35 +503,7 @@ def create_vms(request, host):
         vdis = []
         vbds = []
         for marker in markers.args:
-            vm_name = marker["name"]
-            vm_template = marker["template"]
-
-            logging.info(">> Install VM %r from template %r", vm_name, vm_template)
-
-            vm = host.vm_from_template(vm_name, vm_template)
-
-            # VM is now created, make sure we clean it up on any subsequent failure
-            vms.append(vm)
-
-            if "vdis" in marker:
-                for vdi_def in marker["vdis"]:
-                    sr = SR(host.main_sr_uuid(), host.pool)
-                    vdi = sr.create_vdi(vdi_def["name"], vdi_def["size"])
-                    vdis.append(vdi)
-                    # connect to VM
-                    vbd = vm.create_vbd(vdi_def["device"], vdi.uuid)
-                    vbds.append(vbd)
-                    vbd.param_set(param_name="userdevice", value=vdi_def["userdevice"])
-
-            if "vifs" in marker:
-                for vif_def in marker["vifs"]:
-                    vm.create_vif(vif_def["index"], vif_def["network_uuid"])
-
-            if "params" in marker:
-                for param_def in marker["params"]:
-                    logging.info("Setting param %s", param_def)
-                    vm.param_set(**param_def)
-
+            _create_vm(marker, host, vms, vdis, vbds)
         yield vms
 
     except Exception:
@@ -549,6 +521,36 @@ def create_vms(request, host):
             logging.info("<< Destroy VM %s", vm.uuid)
             vm.destroy(verify=True)
 
+def _create_vm(marker, host, vms, vdis, vbds):
+    vm_name = marker["name"]
+    vm_template = marker["template"]
+
+    logging.info(">> Install VM %r from template %r", vm_name, vm_template)
+
+    vm = host.vm_from_template(vm_name, vm_template)
+
+    # VM is now created, make sure we clean it up on any subsequent failure
+    vms.append(vm)
+
+    if "vdis" in marker:
+        for vdi_def in marker["vdis"]:
+            sr = SR(host.main_sr_uuid(), host.pool)
+            vdi = sr.create_vdi(vdi_def["name"], vdi_def["size"])
+            vdis.append(vdi)
+            # connect to VM
+            vbd = vm.create_vbd(vdi_def["device"], vdi.uuid)
+            vbds.append(vbd)
+            vbd.param_set(param_name="userdevice", value=vdi_def["userdevice"])
+
+    if "vifs" in marker:
+        for vif_def in marker["vifs"]:
+            vm.create_vif(vif_def["index"], vif_def["network_uuid"])
+
+    if "params" in marker:
+        for param_def in marker["params"]:
+            logging.info("Setting param %s", param_def)
+            vm.param_set(**param_def)
+
 @pytest.fixture(scope="module")
 def running_vm(imported_vm):
     vm = imported_vm