Refactor command execution in TerminalEnvVarInjector to use command API and update related tests

Author: eleanorjboyd

.github/instructions/testing-workflow.instructions.md

@@ -235,9 +235,25 @@ interface FunctionAnalysis {
 import * as sinon from 'sinon';
 import * as workspaceApis from '../../common/workspace.apis'; // Wrapper functions
 
-// Stub wrapper functions, not VS Code APIs directly
-// Always mock wrapper functions (e.g., workspaceApis.getConfiguration()) instead of
-// VS Code APIs directly to avoid stubbing issues
+// ❌ WRONG - stubbing raw VS Code modules causes errors
+import { commands } from 'vscode';
+const mockExecuteCommand = sinon.stub(commands, 'executeCommand').resolves();
+// Error: TypeError: Cannot stub non-existent property executeCommand
+
+// ✅ CORRECT - stub the wrapper function from common API layer
+import * as commandApi from '../../common/command.api';
+const mockExecuteCommand = sinon.stub(commandApi, 'executeCommand').resolves();
+
+// CRITICAL: Always check the implementation's imports first
+// If the code uses wrapper functions like these, stub the wrapper:
+// - commandApi.executeCommand() → stub commandApi.executeCommand
+// - workspaceApis.getConfiguration() → stub workspaceApis.getConfiguration
+// - windowApis.showInformationMessage() → stub windowApis.showInformationMessage
+// - workspaceApis.getWorkspaceFolder() → stub workspaceApis.getWorkspaceFolder
+//
+// Why? Raw VS Code modules aren't exported in the test environment, causing
+// "Cannot stub non-existent property" errors when trying to stub them directly.
+
 const mockGetConfiguration = sinon.stub(workspaceApis, 'getConfiguration');
 ```
 
@@ -574,6 +590,7 @@ envConfig.inspect
 -   Untestable Node.js APIs → Create proxy abstraction functions (use function overloads to preserve intelligent typing while making functions mockable)
 
 ## 🧠 Agent Learnings
+
 -   Avoid testing exact error messages or log output - assert only that errors are thrown or rejection occurs to prevent brittle tests (1)
 -   Create shared mock helpers (e.g., `createMockLogOutputChannel()`) instead of duplicating mock setup across multiple test files (1)
-
+-   When stubbing VS Code API functions in unit tests, always check the implementation imports first - if the code uses wrapper functions (like `commandApi.executeCommand()`, `workspaceApis.getConfiguration()`, `windowApis.showInformationMessage()`), stub the wrapper function instead of the raw VS Code module. Stubbing raw VS Code modules (e.g., `sinon.stub(commands, 'executeCommand')`) causes "Cannot stub non-existent property" errors because those modules aren't exported in the test environment (2)

src/features/terminal/terminalEnvVarInjector.ts

@@ -4,13 +4,13 @@
 import * as fse from 'fs-extra';
 import * as path from 'path';
 import {
-    commands,
     Disposable,
     EnvironmentVariableScope,
     GlobalEnvironmentVariableCollection,
     workspace,
     WorkspaceFolder,
 } from 'vscode';
+import { executeCommand } from '../../common/command.api';
 import { Common } from '../../common/localize';
 import { traceError, traceVerbose } from '../../common/logging';
 import { getGlobalPersistentState } from '../../common/persistentState';
@@ -210,7 +210,7 @@ export class TerminalEnvVarInjector implements Disposable {
         );
 
         if (result === Common.openSettings) {
-            await commands.executeCommand('workbench.action.openSettings', 'python.terminal.useEnvFile');
+            await executeCommand('workbench.action.openSettings', 'python.terminal.useEnvFile');
             traceVerbose('TerminalEnvVarInjector: User opened settings for useEnvFile');
         } else if (result === Common.dontShowAgain) {
             await state.set(TerminalEnvVarInjector.DONT_SHOW_ENV_FILE_NOTIFICATION_KEY, true);

src/test/features/terminalEnvVarInjectorNotification.unit.test.ts

@@ -4,7 +4,8 @@
 import * as assert from 'node:assert';
 import * as sinon from 'sinon';
 import * as typeMoq from 'typemoq';
-import { commands, GlobalEnvironmentVariableCollection, Uri, workspace } from 'vscode';
+import { GlobalEnvironmentVariableCollection, Uri, workspace } from 'vscode';
+import * as commandApi from '../../common/command.api';
 import { Common } from '../../common/localize';
 import * as persistentState from '../../common/persistentState';
 import * as windowApis from '../../common/window.apis';
@@ -74,7 +75,7 @@ suite('TerminalEnvVarInjector Notification Tests', () => {
         mockShowInformationMessage = sinon.stub(windowApis, 'showInformationMessage').resolves(undefined);
 
         // Setup executeCommand mock
-        mockExecuteCommand = sinon.stub(commands, 'executeCommand').resolves();
+        mockExecuteCommand = sinon.stub(commandApi, 'executeCommand').resolves();
 
         // Setup environment variable change event handler - will be overridden in tests
         envVarManager