extension/settings: add support for multiple test env files

New Setting: go.testEnvFiles
Added go.testEnvFiles setting that accepts an array of environment file paths
Allows loading multiple .env files in a specific order for test execution
Later files in the array override variables from earlier files

Backward Compatibility
Existing go.testEnvFile setting continues to work as before
Marked go.testEnvFile as deprecated with appropriate VS Code deprecation messaging
When both settings are used together, go.testEnvFile is processed after all files in go.testEnvFiles

Fixes #2473

Author: Copilot

extension/package-lock.json

@@ -1438,7 +1438,17 @@
         "go.testEnvFile": {
           "type": "string",
           "default": null,
-          "description": "Absolute path to a file containing environment variables definitions. File contents should be of the form key=value.",
+          "description": "Absolute path to a file containing environment variables definitions. File contents should be of the form key=value. (Deprecated: Use go.testEnvFiles instead)",
+          "scope": "resource",
+          "deprecationMessage": "Use go.testEnvFiles instead"
+        },
+        "go.testEnvFiles": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          },
+          "default": [],
+          "description": "Array of absolute paths to files containing environment variables definitions. File contents should be of the form key=value.",
           "scope": "resource"
         },
         "go.testFlags": {

extension/package.json

@@ -19,7 +19,7 @@ import { getCurrentPackage } from './goModules';
 import { GoDocumentSymbolProvider } from './goDocumentSymbols';
 import { getNonVendorPackages } from './goPackages';
 import { getBinPath, getCurrentGoPath, getTempFilePath, LineBuffer, resolvePath } from './util';
-import { parseEnvFile } from './utils/envUtils';
+import { parseEnvFile, parseEnvFiles } from './utils/envUtils';
 import {
 	getEnvPath,
 	expandFilePathInOutput,
@@ -111,12 +111,28 @@ export function getTestEnvVars(config: vscode.WorkspaceConfiguration): any {
 	const envVars = toolExecutionEnvironment();
 	const testEnvConfig = config['testEnvVars'] || {};
 
-	let fileEnv: { [key: string]: any } = {};
-	let testEnvFile = config['testEnvFile'];
+	// Collect environment files from both settings
+	const envFiles: string[] = [];
+
+	// Add files from the new testEnvFiles setting (array)
+	const testEnvFiles = config['testEnvFiles'] || [];
+	if (Array.isArray(testEnvFiles)) {
+		envFiles.push(...testEnvFiles);
+	}
+
+	// Add the deprecated testEnvFile setting (single file) for backward compatibility
+	const testEnvFile = config['testEnvFile'];
 	if (testEnvFile) {
-		testEnvFile = resolvePath(testEnvFile);
+		envFiles.push(testEnvFile);
+	}
+
+	// Parse all environment files
+	let fileEnv: { [key: string]: any } = {};
+	if (envFiles.length > 0) {
 		try {
-			fileEnv = parseEnvFile(testEnvFile, envVars);
+			// Resolve paths for all files
+			const resolvedFiles = envFiles.map((file) => resolvePath(file));
+			fileEnv = parseEnvFiles(resolvedFiles, envVars);
 		} catch (e) {
 			console.log(e);
 		}

extension/src/testUtils.ts

@@ -0,0 +1,61 @@
+/*---------------------------------------------------------
+ * Copyright (C) Microsoft Corporation. All rights reserved.
+ * Licensed under the MIT License. See LICENSE in the project root for license information.
+ *--------------------------------------------------------*/
+
+import assert from 'assert';
+import path from 'path';
+import fs from 'fs';
+import os from 'os';
+import { parseEnvFiles } from '../../src/utils/envUtils';
+
+suite('parseEnvFiles Tests', () => {
+	let tmpDir: string;
+
+	setup(() => {
+		tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'go-test-env-'));
+	});
+
+	teardown(() => {
+		if (tmpDir && fs.existsSync(tmpDir)) {
+			fs.rmdirSync(tmpDir, { recursive: true });
+		}
+	});
+
+	test('should handle empty array', () => {
+		const result = parseEnvFiles([]);
+		assert.deepStrictEqual(result, {});
+	});
+
+	test('should handle undefined input', () => {
+		const result = parseEnvFiles(undefined);
+		assert.deepStrictEqual(result, {});
+	});
+
+	test('should handle array of files', () => {
+		const envFile1 = path.join(tmpDir, 'first.env');
+		const envFile2 = path.join(tmpDir, 'second.env');
+
+		fs.writeFileSync(envFile1, 'VAR1=value1\nSHARED=from_first');
+		fs.writeFileSync(envFile2, 'VAR2=value2\nSHARED=from_second');
+
+		const result = parseEnvFiles([envFile1, envFile2]);
+
+		assert.strictEqual(result.VAR1, 'value1');
+		assert.strictEqual(result.VAR2, 'value2');
+		// Later files should override earlier ones
+		assert.strictEqual(result.SHARED, 'from_second');
+	});
+
+	test('should handle mixed valid and invalid files', () => {
+		const validFile = path.join(tmpDir, 'valid.env');
+		const invalidFile = path.join(tmpDir, 'nonexistent.env');
+
+		fs.writeFileSync(validFile, 'VALID_VAR=valid_value');
+
+		// This should throw when trying to parse invalid file
+		assert.throws(() => {
+			parseEnvFiles([validFile, invalidFile]);
+		});
+	});
+});