diff --git a/core/src/utils/test/theme.spec.ts b/core/src/utils/test/theme.spec.ts
new file mode 100644
index 0000000000..0e3799f0e0
--- /dev/null
+++ b/core/src/utils/test/theme.spec.ts
@@ -0,0 +1,32 @@
+import { getClassList } from '../theme';
+
+describe('theme utils', () => {
+  describe('getClassList()', () => {
+    it('should parse string', () => {
+      expect(getClassList(' class class-event     THEME-ios-bar-button')).toEqual([
+        'class', 'class-event', 'THEME-ios-bar-button'
+      ]);
+      expect(getClassList('')).toEqual([]);
+      expect(getClassList('  ')).toEqual([]);
+    });
+
+    it('should pass array', () => {
+      expect(getClassList([
+        'class', 'class-event', 'THEME-ios-bar-button'
+      ])).toEqual([
+        'class', 'class-event', 'THEME-ios-bar-button'
+      ]);
+      expect(getClassList([
+        'class   ', '   class-event', '  THEME-ios-bar-button  '
+      ])).toEqual([
+        'class', 'class-event', 'THEME-ios-bar-button'
+      ]);
+
+      expect(getClassList([
+        'class   ', null, undefined, '', '   class-event', '  THEME-ios-bar-button  '
+      ] as any)).toEqual([
+        'class', 'class-event', 'THEME-ios-bar-button'
+      ]);
+    });
+  });
+});