fix: windows ComSpec env variable name

This looks like a typo in the original implementation, based on
references to this same variable in the npm cli config.

PR-URL: #27
Credit: @ruyadorno
Close: #27
Reviewed-by: @wraithgar

README.md

@@ -103,7 +103,7 @@ terminal, then it is up to the user to end it, of course.
   - The `package.json` fields described in
     [RFC183](https://github.com/npm/rfcs/pull/183/files).
 - `scriptShell` Optional, defaults to `/bin/sh` on Unix, defaults to
-  `env.comspec` or `cmd` on Windows.  Custom script to use to execute the
+  `env.ComSpec` or `cmd` on Windows.  Custom script to use to execute the
   command.
 - `stdio` Optional, defaults to `'pipe'`.  The same as the `stdio` argument
   passed to `child_process` functions in Node.js.  Note that if a stdio

lib/make-spawn-args.js

@@ -8,7 +8,7 @@ const makeSpawnArgs = options => {
   const {
     event,
     path,
-    scriptShell = isWindows ? process.env.comspec || 'cmd' : 'sh',
+    scriptShell = isWindows ? process.env.ComSpec || 'cmd' : 'sh',
     env = {},
     stdio,
     cmd,

test/make-spawn-args.js

@@ -16,8 +16,8 @@ const makeSpawnArgs = requireInject('../lib/make-spawn-args.js', {
 
 if (isWindows) {
   t.test('windows', t => {
-    // with no comspec
-    delete process.env.comspec
+    // with no ComSpec
+    delete process.env.ComSpec
     t.match(makeSpawnArgs({
       event: 'event',
       path: 'path',
@@ -38,8 +38,8 @@ if (isWindows) {
       }
     ])
 
-    // with a funky comspec
-    process.env.comspec = 'blrorp'
+    // with a funky ComSpec
+    process.env.ComSpec = 'blrorp'
     t.match(makeSpawnArgs({
       event: 'event',
       path: 'path',