Index: node_modules/node-gyp/test/test-configure-python.js
===================================================================
--- node_modules/node-gyp/test/test-configure-python.js	(revision 81bc7da776d8cda42939ef4ab350c88d13b4941f)
+++ node_modules/node-gyp/test/test-configure-python.js	(revision 81bc7da776d8cda42939ef4ab350c88d13b4941f)
@@ -0,0 +1,82 @@
+'use strict'
+
+const test = require('tap').test
+const path = require('path')
+const devDir = require('./common').devDir()
+const gyp = require('../lib/node-gyp')
+const requireInject = require('require-inject')
+const configure = requireInject('../lib/configure', {
+  'graceful-fs': {
+    openSync: function () { return 0 },
+    closeSync: function () { },
+    writeFile: function (file, data, cb) { cb() },
+    stat: function (file, cb) { cb(null, {}) },
+    mkdir: function (dir, options, cb) { cb() },
+    promises: {
+      writeFile: function (file, data) { return Promise.resolve(null) }
+    }
+  }
+})
+
+const EXPECTED_PYPATH = path.join(__dirname, '..', 'gyp', 'pylib')
+const SEPARATOR = process.platform === 'win32' ? ';' : ':'
+const SPAWN_RESULT = { on: function () { } }
+
+require('npmlog').level = 'warn'
+
+test('configure PYTHONPATH with no existing env', function (t) {
+  t.plan(1)
+
+  delete process.env.PYTHONPATH
+
+  var prog = gyp()
+  prog.parseArgv([])
+  prog.spawn = function () {
+    t.equal(process.env.PYTHONPATH, EXPECTED_PYPATH)
+    return SPAWN_RESULT
+  }
+  prog.devDir = devDir
+  configure(prog, [], t.fail)
+})
+
+test('configure PYTHONPATH with existing env of one dir', function (t) {
+  t.plan(2)
+
+  var existingPath = path.join('a', 'b')
+  process.env.PYTHONPATH = existingPath
+
+  var prog = gyp()
+  prog.parseArgv([])
+  prog.spawn = function () {
+    t.equal(process.env.PYTHONPATH, [EXPECTED_PYPATH, existingPath].join(SEPARATOR))
+
+    var dirs = process.env.PYTHONPATH.split(SEPARATOR)
+    t.deepEqual(dirs, [EXPECTED_PYPATH, existingPath])
+
+    return SPAWN_RESULT
+  }
+  prog.devDir = devDir
+  configure(prog, [], t.fail)
+})
+
+test('configure PYTHONPATH with existing env of multiple dirs', function (t) {
+  t.plan(2)
+
+  var pythonDir1 = path.join('a', 'b')
+  var pythonDir2 = path.join('b', 'c')
+  var existingPath = [pythonDir1, pythonDir2].join(SEPARATOR)
+  process.env.PYTHONPATH = existingPath
+
+  var prog = gyp()
+  prog.parseArgv([])
+  prog.spawn = function () {
+    t.equal(process.env.PYTHONPATH, [EXPECTED_PYPATH, existingPath].join(SEPARATOR))
+
+    var dirs = process.env.PYTHONPATH.split(SEPARATOR)
+    t.deepEqual(dirs, [EXPECTED_PYPATH, pythonDir1, pythonDir2])
+
+    return SPAWN_RESULT
+  }
+  prog.devDir = devDir
+  configure(prog, [], t.fail)
+})