diff --git a/__tests__/commands/_helpers.js b/__tests__/commands/_helpers.js
index 5e369f6a47..29e6b02dfa 100644
--- a/__tests__/commands/_helpers.js
+++ b/__tests__/commands/_helpers.js
@@ -9,6 +9,7 @@ import {run as check} from '../../src/cli/commands/check.js';
 import * as fs from '../../src/util/fs.js';
 import {Install} from '../../src/cli/commands/install.js';
 import Config from '../../src/config.js';
+import {userHomeDir, setUserHomeDir} from '../../src/util/user-home-dir';
 
 const stream = require('stream');
 const path = require('path');
@@ -101,8 +102,8 @@ export async function run<T, R>(
 
   // remove the lockfile if we create one and it didn't exist before
   const lockfile = await createLockfile(cwd);
-  const homeFolderLocation = process.env.YARN_HOME_FOLDER;
-  process.env.YARN_HOME_FOLDER = path.join(cwd, '.yarn-home');
+  const homeFolderLocation = userHomeDir();
+  setUserHomeDir(path.join(cwd, '.yarn-home'));
 
   // create directories
   await fs.mkdirp(path.join(cwd, '.yarn-global'));
@@ -134,6 +135,6 @@ export async function run<T, R>(
   } catch (err) {
     throw new Error(`${err && err.stack} \nConsole output:\n ${out}`);
   } finally {
-    process.env.YARN_HOME_FOLDER = homeFolderLocation;
+    setUserHomeDir(homeFolderLocation);
   }
 }
diff --git a/src/constants.js b/src/constants.js
index 48d7854b35..2454ff556e 100644
--- a/src/constants.js
+++ b/src/constants.js
@@ -1,7 +1,8 @@
 /* @flow */
 
+import {userHomeDir} from './util/user-home-dir';
+
 const path = require('path');
-const userHome = require('./util/user-home-dir').default;
 
 type Env = {
   [key: string]: ? string
@@ -42,12 +43,12 @@ function getDirectory(category: string): string {
   }
 
   // otherwise use ~/.{category}/yarn
-  return path.join(userHome, `.${category}`, 'yarn');
+  return path.join(userHomeDir(), `.${category}`, 'yarn');
 }
 
 function getCacheDirectory(): string {
   if (process.platform === 'darwin') {
-    return path.join(userHome, 'Library', 'Caches', 'Yarn');
+    return path.join(userHomeDir(), 'Library', 'Caches', 'Yarn');
   }
 
   return getDirectory('cache');
diff --git a/src/registries/npm-registry.js b/src/registries/npm-registry.js
index 176a469918..95c9c3c6c8 100644
--- a/src/registries/npm-registry.js
+++ b/src/registries/npm-registry.js
@@ -10,8 +10,8 @@ import envReplace from '../util/env-replace.js';
 import Registry from './base-registry.js';
 import {addSuffix, removePrefix} from '../util/misc';
 import isRequestToRegistry from './is-request-to-registry.js';
+import {userHomeDir} from '../util/user-home-dir';
 
-const userHome = require('../util/user-home-dir').default;
 const path = require('path');
 const url = require('url');
 const ini = require('ini');
@@ -97,7 +97,7 @@ export default class NpmRegistry extends Registry {
   async getPossibleConfigLocations(filename: string): Promise<Array<[boolean, string, string]>> {
     const possibles = [
       [false, path.join(this.cwd, filename)],
-      [true, this.config.userconfig || path.join(process.env.YARN_HOME_FOLDER || userHome, filename)],
+      [true, this.config.userconfig || path.join(userHomeDir(), filename)],
       [false, path.join(getGlobalPrefix(), filename)],
     ];
 
diff --git a/src/registries/yarn-registry.js b/src/registries/yarn-registry.js
index d000c0ead6..7934a3c4eb 100644
--- a/src/registries/yarn-registry.js
+++ b/src/registries/yarn-registry.js
@@ -7,8 +7,8 @@ import NpmRegistry from './npm-registry.js';
 import stringify from '../lockfile/stringify.js';
 import parse from '../lockfile/parse.js';
 import * as fs from '../util/fs.js';
+import {userHomeDir} from '../util/user-home-dir';
 
-const userHome = require('../util/user-home-dir').default;
 const path = require('path');
 const pkg: { version: string } = require('../../package.json');
 
@@ -46,7 +46,7 @@ export default class YarnRegistry extends NpmRegistry {
   constructor(cwd: string, registries: ConfigRegistries, requestManager: RequestManager) {
     super(cwd, registries, requestManager);
 
-    this.homeConfigLoc = path.join(userHome, '.yarnrc');
+    this.homeConfigLoc = path.join(userHomeDir(), '.yarnrc');
     this.homeConfig = {};
   }
 
diff --git a/src/util/user-home-dir.js b/src/util/user-home-dir.js
index 8ee2490ce6..e10333b669 100644
--- a/src/util/user-home-dir.js
+++ b/src/util/user-home-dir.js
@@ -2,8 +2,14 @@
 const path = require('path');
 const {ROOT_USER} = require('../constants');
 
-const userHomeDir = (process.platform === 'linux' && ROOT_USER) ?
-  path.resolve('/usr/local/share') :
-  require('os').homedir();
+let userHome = (process.platform === 'linux' && ROOT_USER) ?
+path.resolve('/usr/local/share') :
+require('os').homedir();
 
-export default userHomeDir;
+export function userHomeDir(): string {
+  return userHome;
+}
+
+export function setUserHomeDir(injectedUserHome: string) {
+  userHome = injectedUserHome;
+}