diff --git a/test/common/README.md b/test/common/README.md
index 54604568681612..e6371265d8b971 100644
--- a/test/common/README.md
+++ b/test/common/README.md
@@ -376,11 +376,6 @@ Synchronous version of `spawnPwd`.
 
 The realpath of the 'tmp' directory.
 
-### tmpDirName
-* return [<String>]
-
-Name of the temp directory used by tests.
-
 ## Countdown Module
 
 The `Countdown` module provides a simple countdown mechanism for tests that
diff --git a/test/common/index.js b/test/common/index.js
index 838c7b60da21aa..56631aee8759dc 100644
--- a/test/common/index.js
+++ b/test/common/index.js
@@ -40,7 +40,7 @@ exports.fixturesDir = fixturesDir;
 
 // Using a `.` prefixed name, which is the convention for "hidden" on POSIX,
 // gets tools to ignore it by default or by simple rules, especially eslint.
-exports.tmpDirName = '.tmp';
+let tmpDirName = '.tmp';
 // PORT should match the definition in test/testpy/__init__.py.
 exports.PORT = +process.env.NODE_COMMON_PORT || 12346;
 exports.isWindows = process.platform === 'win32';
@@ -165,9 +165,9 @@ exports.refreshTmpDir = function() {
 
 if (process.env.TEST_THREAD_ID) {
   exports.PORT += process.env.TEST_THREAD_ID * 100;
-  exports.tmpDirName += `.${process.env.TEST_THREAD_ID}`;
+  tmpDirName += `.${process.env.TEST_THREAD_ID}`;
 }
-exports.tmpDir = path.join(testRoot, exports.tmpDirName);
+exports.tmpDir = path.join(testRoot, tmpDirName);
 
 let opensslCli = null;
 let inFreeBSDJail = null;
diff --git a/test/parallel/test-fs-realpath.js b/test/parallel/test-fs-realpath.js
index 013e8015147d2f..4ea9bfdf48eb6f 100644
--- a/test/parallel/test-fs-realpath.js
+++ b/test/parallel/test-fs-realpath.js
@@ -111,7 +111,7 @@ function test_simple_relative_symlink(realpath, realpathSync, callback) {
   const entry = `${tmpDir}/symlink`;
   const expected = `${tmpDir}/cycles/root.js`;
   [
-    [entry, `../${common.tmpDirName}/cycles/root.js`]
+    [entry, `../${path.basename(tmpDir)}/cycles/root.js`]
   ].forEach(function(t) {
     try { fs.unlinkSync(t[0]); } catch (e) {}
     console.log('fs.symlinkSync(%j, %j, %j)', t[1], t[0], 'file');