fix tests

Author: the-higgs

jupyter_server/services/kernels/kernelmanager.py

@@ -182,8 +182,11 @@ async def start_kernel(self, kernel_id=None, path=None, **kwargs):
         if kernel_id is None or kernel_id not in self:
             if path is not None:
                 kwargs['cwd'] = self.cwd_for_path(path)
-            kernel_id = await ensure_async(
-                self.pinned_superclass.start_kernel(self, kernel_id=kernel_id, **kwargs))
+            if kernel_id:
+                kernel_id = await ensure_async(self.pinned_superclass.start_kernel(self, kernel_id=kernel_id, **kwargs))
+            else:
+                kernel_id = await ensure_async(self.pinned_superclass.start_kernel(self, **kwargs))
+
             self._kernel_connections[kernel_id] = 0
             self._kernel_ports[kernel_id] = self._kernels[kernel_id].ports
             self.start_watching_activity(kernel_id)