diff --git a/themebuilder/tests/builder-spec.js b/themebuilder/tests/builder-spec.js
index 4221d6bf4656..38eee93b37cc 100644
--- a/themebuilder/tests/builder-spec.js
+++ b/themebuilder/tests/builder-spec.js
@@ -4,7 +4,6 @@ const path = require('path');
 const assert = require('chai').assert;
 const buildTheme = require('../modules/builder').buildTheme;
 const commands = require('../modules/commands');
-const mock = require('mock-require');
 
 const fileReader = (filename) => {
     filename = filename.replace('devextreme-themebuilder/', '');
@@ -120,23 +119,6 @@ describe('Builder - testing exported function', () => {
 });
 
 describe('Check if all widgets can be compiled separately', () => {
-    let buildThemeWithMockedCleanCss = {};
-
-    beforeEach(() => {
-        mock('clean-css', class CleanCss {
-            minify(css) {
-                return { styles: css };
-            }
-        });
-        mock.reRequire('clean-css');
-        mock.reRequire('../modules/less-template-loader');
-        buildThemeWithMockedCleanCss = mock.reRequire('../modules/builder').buildTheme;
-    });
-
-    afterEach(() => {
-        mock.stopAll();
-    });
-
     ['generic.light', 'material.blue.light'].forEach(theme => {
         const ModulesHandler = require('../modules/modules-handler');
         const themesFileContent = fs.readFileSync(path.join(__dirname, '../../styles/theme.less'), 'utf8');
@@ -150,15 +132,16 @@ describe('Check if all widgets can be compiled separately', () => {
                 lessCompiler: lessCompiler,
                 items: [],
                 baseTheme: theme,
-                widgets: [widgetName]
+                widgets: [widgetName],
+                noClean: true
             };
 
             it(`We can build bundle for every widget (${theme}, ${widgetName})`, () => {
-                return buildThemeWithMockedCleanCss(config).then((result) => {
+                return buildTheme(config).then((result) => {
                     assert.isString(result.css, `${widgetName} bundle builded`);
                     assert.deepEqual(result.widgets, [ widgetName ]);
                 });
-            });
+            }).timeout(buildTimeout);
         });
     });
 });
diff --git a/themebuilder/tests/less-template-loader-spec.js b/themebuilder/tests/less-template-loader-spec.js
index e8a812f7cfb1..8f8e074079f8 100644
--- a/themebuilder/tests/less-template-loader-spec.js
+++ b/themebuilder/tests/less-template-loader-spec.js
@@ -602,38 +602,28 @@ describe('LessTemplateLoader', () => {
         };
 
         const lessTemplateLoader = new LessTemplateLoader(config);
-        lessTemplateLoader._makeInfoHeader = emptyHeader;
-
-        const promises = [];
-
-        promises.push(lessTemplateLoader.load(
-            themeName,
-            colorScheme,
-            metadata,
-            []
-        ).then(data => {
-            assert.equal(data.css, `div {
-  font: 20px/20px DXIcons;
-}`);
-        }));
 
         config.noClean = true;
         const lessTemplateLoaderNoClean = new LessTemplateLoader(config);
+
         lessTemplateLoaderNoClean._makeInfoHeader = emptyHeader;
-        promises.push(lessTemplateLoaderNoClean.load(
+        lessTemplateLoader._makeInfoHeader = emptyHeader;
+
+        const testCases = [{
+            loader: lessTemplateLoader,
+            expected: 'div {\n  font: 20px/20px DXIcons;\n}'
+        }, {
+            loader: lessTemplateLoaderNoClean,
+            expected: 'div {\n  font: 14px/1 DXIcons;\n  font-size: 20px;\n  line-height: 20px;\n}\n'
+        }];
+
+        const promises = testCases.map(testCase => testCase.loader.load(
             themeName,
             colorScheme,
             metadata,
             []
-        ).then(data => {
-            assert.equal(data.css, `div {
-  font: 14px/1 DXIcons;
-  font-size: 20px;
-  line-height: 20px;
-}
-`);
-        }));
+        ).then(data => assert.equal(data.css, testCase.expected)));
 
-        return promises;
+        return Promise.all(promises);
     });
 });