diff --git a/package-lock.json b/package-lock.json
index 2d52846aa..8b414f07d 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
 	"name": "intern",
-	"version": "4.2.1-pre",
+	"version": "4.2.2-pre",
 	"lockfileVersion": 1,
 	"requires": true,
 	"dependencies": {
@@ -2758,6 +2758,31 @@
 				"sha.js": "^2.4.8"
 			}
 		},
+		"cross-env": {
+			"version": "5.2.0",
+			"resolved": "https://registry.npmjs.org/cross-env/-/cross-env-5.2.0.tgz",
+			"integrity": "sha512-jtdNFfFW1hB7sMhr/H6rW1Z45LFqyI431m3qU6bFXcQ3Eh7LtBuG3h74o7ohHZ3crrRkkqHlo4jYHFPcjroANg==",
+			"dev": true,
+			"requires": {
+				"cross-spawn": "^6.0.5",
+				"is-windows": "^1.0.0"
+			},
+			"dependencies": {
+				"cross-spawn": {
+					"version": "6.0.5",
+					"resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-6.0.5.tgz",
+					"integrity": "sha512-eTVLrBSt7fjbDygz805pMnstIs2VTBNkRm0qxZd+M7A5XDdxVRWO5MxGBXZhjY4cqLYLdtrGqRf8mBPmzwSpWQ==",
+					"dev": true,
+					"requires": {
+						"nice-try": "^1.0.4",
+						"path-key": "^2.0.1",
+						"semver": "^5.5.0",
+						"shebang-command": "^1.2.0",
+						"which": "^1.2.9"
+					}
+				}
+			}
+		},
 		"cross-spawn": {
 			"version": "5.1.0",
 			"resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-5.1.0.tgz",
diff --git a/package.json b/package.json
index 9bebb3cd9..c4ae67b97 100644
--- a/package.json
+++ b/package.json
@@ -51,9 +51,9 @@
     "devpack": "intern-dev-build && cd _build/src && npm pack && cp *.tgz ../../",
     "clean": "intern-dev-clean",
     "lint": "intern-dev-lint",
-    "release": "INTERN_BUILD=release intern-dev-release",
-    "start": "NODE_PATH=_build node _tests/src/bin/intern.js serveOnly",
-    "test": "NODE_PATH=_build node _tests/src/bin/intern.js",
+    "release": "cross-env INTERN_BUILD=release intern-dev-release",
+    "start": "cross-env NODE_PATH=_build node _tests/src/bin/intern.js serveOnly",
+    "test": "cross-env NODE_PATH=_build node _tests/src/bin/intern.js",
     "preci": "intern-dev-build",
     "ci": "npm test config=@ci",
     "watch": "intern-dev-build watch",
@@ -124,6 +124,7 @@
     "@types/webpack": "~4.1.3",
     "ajv": "~6.4.0",
     "concurrently": "~3.5.0",
+    "cross-env": "~5.2.0",
     "css-loader": "~0.28.11",
     "jsdom": "~11.8.0",
     "lint-staged": "~7.0.5",
@@ -180,4 +181,4 @@
     ]
   },
   "pre-commit": "precommit"
-}
\ No newline at end of file
+}
diff --git a/tests/unit/lib/middleware/instrument.ts b/tests/unit/lib/middleware/instrument.ts
index 5e93d6170..6fa50ab56 100644
--- a/tests/unit/lib/middleware/instrument.ts
+++ b/tests/unit/lib/middleware/instrument.ts
@@ -10,8 +10,10 @@ import {
 	createMockServerContext
 } from '../../../support/unit/mocks';
 import { mockFs, mockPath, MockStats } from '../../../support/unit/nodeMocks';
+import { normalize } from 'path';
 
 const mockRequire = <mocking.MockRequire>intern.getPlugin('mockRequire');
+const testPath = normalize('/base/foo/thing.js');
 
 registerSuite('lib/middleware/instrument', function() {
 	let instrument: typeof _instrument;
@@ -47,7 +49,10 @@ registerSuite('lib/middleware/instrument', function() {
 
 		beforeEach() {
 			fs.__fileData = {
-				'/base/foo/thing.js': { type: 'file', data: 'what a fun time' }
+				[testPath]: {
+					type: 'file',
+					data: 'what a fun time'
+				}
 			};
 			server = createMockServer({
 				basePath: '/base',
@@ -107,7 +112,7 @@ registerSuite('lib/middleware/instrument', function() {
 					},
 
 					directory() {
-						fs.__fileData['/base/foo/thing.js']!.type = 'directory';
+						fs.__fileData[testPath]!.type = 'directory';
 
 						handler(request, response, next);
 
@@ -120,9 +125,8 @@ registerSuite('lib/middleware/instrument', function() {
 						sandbox
 							.stub(fs, 'stat')
 							.callsFake((path: string, callback: any) => {
-								const data =
-									fs.__fileData['/base/foo/thing.js'];
-								fs.__fileData['/base/foo/thing.js'] = undefined;
+								const data = fs.__fileData[testPath];
+								fs.__fileData[testPath] = undefined;
 								callback(
 									undefined,
 									new MockStats(path, data!.type)
diff --git a/webpack.config.ts b/webpack.config.ts
index da7e1e89f..01eb1048d 100644
--- a/webpack.config.ts
+++ b/webpack.config.ts
@@ -12,7 +12,7 @@ const common: Configuration = {
 	module: {
 		rules: [
 			{
-				test: /@dojo\//,
+				test: /@dojo[\\\/]/,
 				use: 'umd-compat-loader'
 			},
 			{
@@ -29,7 +29,7 @@ const common: Configuration = {
 				}
 			}
 		],
-		noParse: /benchmark\/benchmark.js/
+		noParse: /benchmark[\\\/]benchmark.js/
 	},
 	performance: {
 		// Hides a warning about large bundles.