backport: fix change session by moving to async/await promise (PowerShell#1927)

Author: TylerLeonhardt

src/settings.ts

@@ -186,12 +186,12 @@ export function load(): ISettings {
     };
 }
 
-export function change(settingName: string, newValue: any, global: boolean = false): Thenable<void> {
+export async function change(settingName: string, newValue: any, global: boolean = false): Promise<void> {
     const configuration: vscode.WorkspaceConfiguration =
         vscode.workspace.getConfiguration(
             utils.PowerShellLanguageId);
 
-    return configuration.update(settingName, newValue, global);
+    await configuration.update(settingName, newValue, global);
 }
 
 function getWorkspaceSettingsWithDefaults<TSettings>(

test/settings.test.ts

@@ -0,0 +1,22 @@
+/*---------------------------------------------------------
+ * Copyright (C) Microsoft Corporation. All rights reserved.
+ *--------------------------------------------------------*/
+
+import * as assert from "assert";
+import Settings = require("../src/settings");
+
+suite("Settings module", () => {
+    test("Settings load without error", () => {
+        assert.doesNotThrow(Settings.load);
+    });
+
+    test("Settings update correctly", async () => {
+        // then syntax
+        Settings.change("powerShellExePath", "dummypath1", false).then(() =>
+            assert.strictEqual(Settings.load().powerShellExePath, "dummypath1"));
+
+        // async/await syntax
+        await Settings.change("powerShellExePath", "dummypath2", false);
+        assert.strictEqual(Settings.load().powerShellExePath, "dummypath2");
+    });
+});