More azdata tests (#12999)

* More azdata tests

* comment

* fix

extensions/azdata/src/test/testUtils.ts

@@ -0,0 +1,20 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+/**
+ * Asserts that the specified promise was rejected. This is similar to should(..).be.rejected but
+ * allows specifying a message in the thrown Error to add more information to the failure.
+ * @param promise The promise to verify was rejected
+ * @param message The message to include in the error if the promise isn't rejected
+ */
+export async function assertRejected(promise: Promise<any>, message: string): Promise<void> {
+	try {
+		await promise;
+	} catch {
+		return;
+	}
+	throw new Error(message);
+}
+