diff --git a/index.js b/index.js
index a6cf4f5..e2549de 100644
--- a/index.js
+++ b/index.js
@@ -4,6 +4,9 @@ exports = module.exports = lifecycle
 exports.makeEnv = makeEnv
 exports._incorrectWorkingDirectory = _incorrectWorkingDirectory
 
+// for testing
+const platform = process.env.__TESTING_FAKE_PLATFORM__ || process.platform
+const isWindows = platform === 'win32'
 const spawn = require('./lib/spawn')
 const path = require('path')
 const Stream = require('stream').Stream
@@ -20,8 +23,8 @@ const hookStatCache = new Map()
 
 let PATH = 'PATH'
 
-// windows calls it's path 'Path' usually, but this is not guaranteed.
-if (process.platform === 'win32') {
+// windows calls its path 'Path' usually, but this is not guaranteed.
+if (isWindows) {
   PATH = 'Path'
   if (!process.env[PATH]) {
     Object.keys(process.env).forEach(function (e) {
@@ -32,6 +35,8 @@ if (process.platform === 'win32') {
   }
 }
 
+exports._pathEnvName = PATH
+
 function logid (pkg, stage) {
   return pkg._id + '~' + stage + ':'
 }
@@ -123,7 +128,7 @@ function lifecycle_ (pkg, stage, wd, opts, env, cb) {
   }
 
   if (env[PATH]) pathArr.push(env[PATH])
-  env[PATH] = pathArr.join(process.platform === 'win32' ? ';' : ':')
+  env[PATH] = pathArr.join(isWindows ? ';' : ':')
 
   var packageLifecycle = pkg.scripts && pkg.scripts.hasOwnProperty(stage)
 
@@ -166,7 +171,6 @@ function shouldPrependCurrentNodeDirToPATH (opts) {
 
   var isDifferentNodeInPath
 
-  var isWindows = process.platform === 'win32'
   var foundExecPath
   try {
     foundExecPath = which.sync(path.basename(process.execPath), { pathExt: isWindows ? ';' : ':' })
@@ -244,7 +248,7 @@ function runCmd (note, cmd, pkg, env, stage, wd, opts, cb) {
   }
   opts.log.verbose('lifecycle', logid(pkg, stage), 'unsafe-perm in lifecycle', unsafe)
 
-  if (process.platform === 'win32') {
+  if (isWindows) {
     unsafe = true
   }
 
@@ -282,7 +286,7 @@ function runCmd_ (cmd, pkg, env, wd, opts, stage, unsafe, uid, gid, cb_) {
 
   if (customShell) {
     sh = customShell
-  } else if (process.platform === 'win32') {
+  } else if (isWindows) {
     sh = process.env.comspec || 'cmd'
     shFlag = '/d /s /c'
     conf.windowsVerbatimArguments = true
diff --git a/test/win32-set-path.js b/test/win32-set-path.js
new file mode 100644
index 0000000..36842eb
--- /dev/null
+++ b/test/win32-set-path.js
@@ -0,0 +1,39 @@
+// test that windows gets the expected path environ name
+// use Path if present, then PATH, then any /^PATH$/i
+const main = () => {
+  const { spawn } = require('child_process')
+  // [env keys, expect]
+  const cases = [
+    [['Path', 'PATH', 'pAtH'], 'Path'],
+    [['path', 'PATH', 'pAtH'], 'pAtH'],
+    [['Path', 'PATH', 'htap'], 'Path'],
+    [['path', 'PATH', 'htap'], 'PATH']
+  ]
+
+  const t = require('tap')
+  t.plan(cases.length)
+  t.jobs = cases.length
+  cases.forEach(c => {
+    t.test(JSON.stringify(c), t => {
+      t.plan(1)
+      const proc = spawn(process.execPath, [__filename].concat(c[0]))
+      proc.stderr.pipe(process.stderr)
+      const out = []
+      proc.stdout.on('data', d => out.push(d))
+      proc.on('close', () => t.equal(Buffer.concat(out).toString().trim(), c[1]))
+    })
+  })
+}
+
+const child = () => {
+  process.env = {
+    __TESTING_FAKE_PLATFORM__: 'win32',
+    [process.argv[2]]: 1,
+    [process.argv[3] || 'ignore']: 2,
+    [process.argv[4] || 'blerp']: 3
+  }
+
+  console.log(require('../')._pathEnvName)
+}
+
+if (process.argv[2]) { child() } else { main() }