diff --git a/src/common/deepmerge.js b/src/common/deepmerge.js
new file mode 100644
index 00000000..4b5a649c
--- /dev/null
+++ b/src/common/deepmerge.js
@@ -0,0 +1,10 @@
+const deepmerge = require('deepmerge');
+
+function deepMergeProxy(x, y, options) {
+  if (process.env.TEST) {
+    return deepmerge(x, y, options);
+  }
+  return deepmerge.default(x, y, options); // due to webpack conversion
+}
+
+module.exports = deepMergeProxy;
diff --git a/src/common/settings.js b/src/common/settings.js
index 67878da5..b0ec9116 100644
--- a/src/common/settings.js
+++ b/src/common/settings.js
@@ -3,10 +3,7 @@
 const fs = require('fs');
 
 const path = require('path');
-let deepmerge = require('deepmerge').default;
-if (process.env.TEST) {
-  deepmerge = require('deepmerge'); // eslint-disable-line
-}
+const deepmerge = require('./deepmerge');
 
 const settingsVersion = 1;
 const baseConfig = require('./config/base.json');
diff --git a/test/modules/environment.js b/test/modules/environment.js
index 4fd19f02..ffe8abc7 100644
--- a/test/modules/environment.js
+++ b/test/modules/environment.js
@@ -1,5 +1,4 @@
 'use strict';
-process.env.TEST = 'test';
 
 const chai = require('chai');
 chai.should();
diff --git a/test/specs/settings_test.js b/test/specs/settings_test.js
index 8db72848..071fcc99 100644
--- a/test/specs/settings_test.js
+++ b/test/specs/settings_test.js
@@ -2,6 +2,14 @@ const settings = require('../../src/common/settings');
 const deepmerge = require('deepmerge');
 
 describe('common/settings.js', () => {
+  before(() => {
+    process.env.TEST = 1;
+  });
+
+  after(() => {
+    delete process.env.TEST;
+  });
+
   it('should upgrade v0 config file', () => {
     const v0Config = {
       url: 'https://example.com/team'