test: don't re-order package.json on install

Fixes: #10063
Credit: @substack
Reviewed-By: @othiym23
PR-URL: #10185

test/tap/install-package-json-order.js

@@ -0,0 +1,62 @@
+var test = require('tap').test
+var path = require('path')
+var rimraf = require('rimraf')
+var mkdirp = require('mkdirp')
+var spawn = require('child_process').spawn
+var npm = require.resolve('../../bin/npm-cli.js')
+var node = process.execPath
+var pkg = path.resolve(__dirname, 'install-package-json-order')
+var workdir = path.join(pkg, 'workdir')
+var tmp = path.join(pkg, 'tmp')
+var cache = path.join(pkg, 'cache')
+var fs = require('fs')
+var osenv = require('osenv')
+
+test('package.json sorting after install', function (t) {
+  var packageJson = path.resolve(pkg, 'package.json')
+  var installedPackage = path.resolve(workdir,
+    'node_modules/install-package-json-order/package.json')
+
+  cleanup()
+  mkdirp.sync(cache)
+  mkdirp.sync(tmp)
+  mkdirp.sync(workdir)
+  setup()
+
+  var before = JSON.parse(fs.readFileSync(packageJson).toString())
+  var child = spawn(node, [npm, 'install', pkg], { cwd: workdir })
+
+  child.on('close', function (code) {
+    t.equal(code, 0, 'npm install exited with code')
+    var result = fs.readFileSync(installedPackage, 'utf8')
+    var resultAsJson = JSON.parse(result)
+    t.same(resultAsJson.array, before.array)
+    t.end()
+  })
+})
+
+test('cleanup', function (t) {
+  cleanup()
+  t.pass('cleaned up')
+  t.end()
+})
+
+function setup () {
+  mkdirp.sync(pkg)
+
+  fs.writeFileSync(path.resolve(pkg, 'package.json'), JSON.stringify({
+    'name': 'install-package-json-order',
+    'version': '0.0.0',
+    'array': [ 'one', 'two', 'three' ]
+  }, null, 2), 'utf8')
+  fs.writeFileSync(path.resolve(workdir, 'package.json'), JSON.stringify({
+    'name': 'install-package-json-order-work',
+    'version': '0.0.0'
+  }, null, 2), 'utf8')
+}
+
+function cleanup () {
+  process.chdir(osenv.tmpdir())
+  rimraf.sync(cache)
+  rimraf.sync(pkg)
+}