Added mockable isInstanceOf util (#79-2)

src/controllers/ExtensionController.ts

@@ -19,6 +19,7 @@ import {
   assertDefined,
   getEditorForUri,
   getTempDir,
+  isInstanceOf,
   isSupportedLanguageId,
   Logger,
   OutputChannelWithHistory,
@@ -543,7 +544,7 @@ export class ExtensionController implements Disposable {
     const connectionState =
       await this._connectionController.getOrCreateConnection(uri);
 
-    if (connectionState instanceof DhService) {
+    if (isInstanceOf(connectionState, DhService)) {
       await connectionState?.runEditorCode(editor, selectionOnly === true);
     }
   };

src/providers/ServerConnectionTreeProvider.ts

@@ -6,7 +6,7 @@ import type {
   ConnectionState,
   ServerConnectionNode,
 } from '../types';
-import { sortByStringProp } from '../util';
+import { isInstanceOf, sortByStringProp } from '../util';
 import { DhService } from '../services';
 
 /**
@@ -30,7 +30,7 @@ export class ServerConnectionTreeProvider extends TreeDataProviderBase<ServerCon
     }
 
     const [consoleType] =
-      connectionOrUri instanceof DhService && connectionOrUri.isInitialized
+      isInstanceOf(connectionOrUri, DhService) && connectionOrUri.isInitialized
         ? await connectionOrUri.getConsoleTypes()
         : [];
 

src/services/ServerManager.ts

@@ -13,7 +13,12 @@ import type {
   ConnectionState,
   ServerState,
 } from '../types';
-import { getInitialServerStates, isDisposable, Logger } from '../util';
+import {
+  getInitialServerStates,
+  isDisposable,
+  isInstanceOf,
+  Logger,
+} from '../util';
 import { URLMap } from './URLMap';
 import { URIMap } from './URIMap';
 import DhService from './DhService';
@@ -276,7 +281,7 @@ export class ServerManager implements IServerManager {
     const uri = editor.document.uri;
 
     const isConsoleTypeSupported =
-      connectionState instanceof DhService &&
+      isInstanceOf(connectionState, DhService) &&
       (await connectionState.supportsConsoleType(
         editor.document.languageId as ConsoleType
       ));

src/util/index.ts

@@ -1,5 +1,6 @@
 export * from './assertUtil';
 export * from './dataUtils';
+export * from './isInstanceOf';
 export * from './isDisposable';
 export * from './Logger';
 export * from './OutputChannelWithHistory';

src/util/isInstanceOf.ts

@@ -0,0 +1,15 @@
+/**
+ * Type guard wrapper of `instanceof` operator. This is purely so we can mock
+ * instanceof checks in unit tests since `instanceof` is already a type guard.
+ * @param value The value to check
+ * @param type The type to check against
+ * @returns `true` if `value` is an instance of `type`
+ */
+export function isInstanceOf<T>(
+  value: unknown,
+  // Possible we'll need to include non-abstract constructor type, but this seems
+  // to work for both abstract and non-abstract constructors.
+  type: abstract new (...args: any[]) => T
+): value is T {
+  return value instanceof type;
+}

src/util/serverUtils.ts

@@ -10,6 +10,7 @@ import type {
 import { PIP_SERVER_STATUS_DIRECTORY, SERVER_LANGUAGE_SET } from '../common';
 import { getTempDir } from './tmpUtils';
 import { DhService } from '../services';
+import { isInstanceOf } from './isInstanceOf';
 
 /**
  * Get initial server states based on server configs.
@@ -113,7 +114,7 @@ export async function* iterateConnectionsForConsoleType(
 ): AsyncGenerator<ConnectionState, void, unknown> {
   for (const connection of connections) {
     const isConsoleTypeSupported =
-      connection instanceof DhService &&
+      isInstanceOf(connection, DhService) &&
       (await connection.supportsConsoleType(consoleType));
 
     if (isConsoleTypeSupported) {

src/util/treeViewUtils.spec.ts

@@ -19,9 +19,11 @@ import type {
   VariableDefintion,
   VariableType,
 } from '../types';
+import { isInstanceOf } from './isInstanceOf';
 
 // See __mocks__/vscode.ts for the mock implementation
 vi.mock('vscode');
+vi.mock('../util/isInstanceOf.ts');
 
 const variableTypes: readonly VariableType[] = [
   'deephaven.plot.express.DeephavenFigure',
@@ -54,6 +56,8 @@ describe('getPanelConnectionTreeItem', () => {
         getConsoleTypes,
       } as IDhService;
 
+      vi.mocked(isInstanceOf).mockReturnValue(true);
+
       const actual = await getPanelConnectionTreeItem(connection);
       expect(actual).toMatchSnapshot();
     }

src/util/treeViewUtils.ts

@@ -13,6 +13,7 @@ import {
   type ServerTreeItemContextValue,
 } from '../common';
 import { DhService } from '../services';
+import { isInstanceOf } from './isInstanceOf';
 
 /**
  * Get a tree item vscode.ThemeIcon for a variable type.
@@ -54,7 +55,7 @@ export async function getPanelConnectionTreeItem(
   connection: ConnectionState
 ): Promise<vscode.TreeItem> {
   const [consoleType] =
-    connection instanceof DhService && connection.isInitialized
+    isInstanceOf(connection, DhService) && connection.isInitialized
       ? await connection.getConsoleTypes()
       : [];