Notebooks: Adding Change Kernel API, 3 Integration Tests (#5287)

* Notebook change kernel

* Fix notifying of k change too many times add tests

* Fix broken unit test

* Deal with comment

src/sql/workbench/parts/notebook/models/clientSession.ts

@@ -264,8 +264,11 @@ export class ClientSession implements IClientSession {
 	private async updateCachedKernelSpec(): Promise<void> {
 		this._cachedKernelSpec = undefined;
 		let kernel = this.kernel;
-		if (kernel && kernel.isReady) {
-			this._cachedKernelSpec = await this.kernel.getSpec();
+		if (kernel) {
+			await kernel.ready;
+			if (kernel.isReady) {
+				this._cachedKernelSpec = await kernel.getSpec();
+			}
 		}
 	}
 

src/sql/workbench/parts/notebook/models/modelInterfaces.ts

@@ -332,6 +332,11 @@ export interface INotebookModel {
 	 */
 	readonly contentChanged: Event<NotebookContentChange>;
 
+	/**
+	 * Event fired on notebook provider change
+	 */
+	readonly onProviderIdChange: Event<string>;
+
 	/**
 	 * The trusted mode of the Notebook
 	 */

src/sql/workbench/parts/notebook/models/notebookModel.ts

@@ -457,10 +457,6 @@ export class NotebookModel extends Disposable implements INotebookModel {
 				}
 			}
 			this._onClientSessionReady.fire(clientSession);
-			this._kernelChangedEmitter.fire({
-				oldValue: undefined,
-				newValue: clientSession.kernel
-			});
 		}
 	}