test: check that `process.execPath` is a realpath

This test is only here to ensure consistent cross-platform behaviour.

PR-URL: https://github.com/nodejs/node/pull/9229
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

test/parallel/test-process-execpath.js

@@ -0,0 +1,28 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const child_process = require('child_process');
+const path = require('path');
+const fs = require('fs');
+
+assert.strictEqual(process.execPath, fs.realpathSync(process.execPath));
+
+if (common.isWindows) {
+  common.skip('symlinks are weird on windows');
+  return;
+}
+
+if (process.argv[2] === 'child') {
+  // The console.log() output is part of the test here.
+  console.log(process.execPath);
+} else {
+  common.refreshTmpDir();
+
+  const symlinkedNode = path.join(common.tmpDir, 'symlinked-node');
+  fs.symlinkSync(process.execPath, symlinkedNode);
+
+  const proc = child_process.spawnSync(symlinkedNode, [__filename, 'child']);
+  assert.strictEqual(proc.stderr.toString(), '');
+  assert.strictEqual(proc.stdout.toString(), `${process.execPath}\n`);
+  assert.strictEqual(proc.status, 0);
+}