diff --git a/package.json b/package.json
index e7ba719e3..10c769361 100644
--- a/package.json
+++ b/package.json
@@ -22,14 +22,16 @@
   "scripts": {
     "lint": "tslint \"src/**/*.ts\" --project tsconfig.json",
     "lint-fix": "tslint \"src/**/*.ts\" --project tsconfig.json --fix",
-    "clean": "rimraf dist && rimraf tsconfig.schema.json && rimraf tsconfig.schemastore-schema.json",
-    "build": "npm run clean && npm run build-tsc && npm run build-configSchema",
+    "clean": "rimraf dist && rimraf tsconfig.schema.json && rimraf tsconfig.schemastore-schema.json && rimraf tests/ts-node-packed.tgz",
+    "build": "npm run build-nopack && npm run build-pack",
+    "build-nopack": "npm run clean && npm run build-tsc && npm run build-configSchema",
     "build-tsc": "tsc",
     "build-configSchema": "typescript-json-schema --topRef --refs --validationKeywords allOf --out tsconfig.schema.json tsconfig.json TsConfigSchema && node --require ./register ./scripts/create-merged-schema",
+    "build-pack": "node ./scripts/build-pack.js",
     "test-spec": "mocha dist/**/*.spec.js -R spec --bail",
     "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- \"dist/**/*.spec.js\" -R spec --bail",
     "test": "npm run build && npm run lint && npm run test-cov",
-    "prepare": "npm run build"
+    "prepare": "npm run build-nopack"
   },
   "engines": {
     "node": ">=6.0.0"
diff --git a/scripts/build-pack.js b/scripts/build-pack.js
new file mode 100644
index 000000000..38811e99c
--- /dev/null
+++ b/scripts/build-pack.js
@@ -0,0 +1,20 @@
+// Written in JS to support Windows
+// Would otherwise be written as inline bash in package.json script
+
+const { exec } = require('child_process')
+const { mkdtempSync, writeFileSync, readFileSync, unlinkSync, rmdirSync, readdirSync } = require('fs')
+const { join } = require('path')
+
+const testDir = join(__dirname, '../tests')
+const tarballPath = join(testDir, 'ts-node-packed.tgz')
+const tempDir = mkdtempSync(join(testDir, 'tmp'))
+exec(`npm pack "${join(__dirname, '..')}"`, { cwd: tempDir }, (err, stdout) => {
+  if (err) {
+    console.error(err)
+    process.exit(1)
+  }
+  const tempTarballPath = join(tempDir, readdirSync(tempDir)[0])
+  writeFileSync(tarballPath, readFileSync(tempTarballPath))
+  unlinkSync(tempTarballPath)
+  rmdirSync(tempDir)
+})
diff --git a/src/index.spec.ts b/src/index.spec.ts
index 5a55ac1cb..fd4f12b59 100644
--- a/src/index.spec.ts
+++ b/src/index.spec.ts
@@ -10,9 +10,7 @@ import * as promisify from 'util.promisify'
 
 const execP = promisify(exec)
 
-const ROOT_DIR = join(__dirname, '..')
 const TEST_DIR = join(__dirname, '../tests')
-const TARBALL_PATH = join(TEST_DIR, 'ts-node-packed.tgz')
 const PROJECT = join(TEST_DIR, 'tsconfig.json')
 const BIN_PATH = join(TEST_DIR, 'node_modules/.bin/ts-node')
 const BIN_SCRIPT_PATH = join(TEST_DIR, 'node_modules/.bin/ts-node-script')
@@ -22,12 +20,6 @@ const SOURCE_MAP_REGEXP = /\/\/# sourceMappingURL=data:application\/json;charset
 // Pack and install ts-node locally, necessary to test package "exports"
 before(async function () {
   this.timeout(30000)
-  const tempDir = mkdtempSync(join(TEST_DIR, 'tmp'))
-  await execP(`npm pack --ignore-scripts "${ROOT_DIR}"`, { cwd: tempDir })
-  const tarballPath = join(tempDir, readdirSync(tempDir)[0])
-  writeFileSync(TARBALL_PATH, readFileSync(tarballPath))
-  unlinkSync(tarballPath)
-  rmdirSync(tempDir)
   await execP(`npm install`, { cwd: TEST_DIR })
   const packageLockPath = join(TEST_DIR, 'package-lock.json')
   existsSync(packageLockPath) && unlinkSync(packageLockPath)