Fix notebook document selector not being a list in capabilities (#454)

Author: smacke

pylsp/python_lsp.py

@@ -295,7 +295,7 @@ def capabilities(self):
                 "openClose": True,
             },
             "notebookDocumentSync": {
-                "notebookSelector": {"cells": [{"language": "python"}]}
+                "notebookSelector": [{"cells": [{"language": "python"}]}]
             },
             "workspace": {
                 "workspaceFolders": {"supported": True, "changeNotifications": True}

test/test_notebook_document.py

@@ -33,7 +33,8 @@ def test_initialize(client_server_pair):
         },
     ).result(timeout=CALL_TIMEOUT_IN_SECONDS)
     assert server.workspace is not None
-    assert "notebookDocumentSync" in response["capabilities"].keys()
+    selector = response["capabilities"]["notebookDocumentSync"]["notebookSelector"]
+    assert isinstance(selector, list)
 
 
 @pytest.mark.skipif(IS_WIN, reason="Flaky on Windows")