tests: pass tests on Windows without Admin privs

1. Skip testing Cygwin bash shim when coverage is enabled, since this
   doesn't work, and probably never will.
2. Create symbolic links to directories rather than files, so that
   Administrative privileges are not required.

test/bin/windows-shims.js

@@ -85,6 +85,11 @@ for (const [name, bash] of bashes) {
     continue
   }
 
+  if (bash === cygwinBash && process.env.NYC_CONFIG) {
+    t.skip('Cygwin does not play nicely with NYC, run without coverage')
+    continue
+  }
+
   t.test(name, async t => {
     t.plan(2)
     t.test('npm', async t => {

test/coverage-map.js

@@ -7,6 +7,10 @@ const coverageMap = (filename) => {
     return glob.sync(`${dir}/**/*.js`)
       .map(f => relative(process.cwd(), f))
   }
+  if (/windows-shims\.js$/.test(filename)) {
+    // this one doesn't provide any coverage nyc can track
+    return []
+  }
   if (/^test\/(lib|bin)\//.test(filename))
     return filename.replace(/^test\//, '')
   return []

test/lib/doctor.js

@@ -487,7 +487,7 @@ test('node versions', t => {
         const dir = st.testdir({
           cache: {
             one: 'one',
-            link: st.fixture('symlink', './one'),
+            link: st.fixture('symlink', './baddir'),
             unreadable: 'unreadable',
             baddir: {},
           },

test/lib/npm.js

@@ -1,5 +1,4 @@
 const t = require('tap')
-const fs = require('fs')
 
 // delete this so that we don't have configs from the fact that it
 // is being run by 'npm test'
@@ -21,7 +20,7 @@ for (const env of Object.keys(process.env).filter(e => /^npm_/.test(e))) {
   delete process.env[env]
 }
 
-const { resolve } = require('path')
+const { resolve, dirname } = require('path')
 
 const actualPlatform = process.platform
 
@@ -249,13 +248,11 @@ t.test('npm.load', t => {
     const node = actualPlatform === 'win32' ? 'node.exe' : 'node'
     const dir = t.testdir({
       '.npmrc': 'foo = bar',
+      bin: t.fixture('symlink', dirname(process.execPath)),
     })
 
-    // create manually to set the 'file' option in windows
-    fs.symlinkSync(process.execPath, resolve(dir, node), 'file')
-
     const PATH = process.env.PATH || process.env.Path
-    process.env.PATH = dir
+    process.env.PATH = resolve(dir, 'bin')
     const { execPath, argv: processArgv } = process
     process.argv = [
       node,
@@ -294,7 +291,7 @@ t.test('npm.load', t => {
         [
           'verbose',
           'node symlink',
-          resolve(dir, node),
+          resolve(dir, 'bin', node),
         ],
         [
           'timing',
@@ -303,7 +300,7 @@ t.test('npm.load', t => {
         ],
       ])
       logs.length = 0
-      t.equal(process.execPath, resolve(dir, node))
+      t.equal(process.execPath, resolve(dir, 'bin', node))
     })
 
     await npm.commands.ll([], (er) => {