diff --git a/src/test/java/ua/net/uid/utils/helpers/StringHelperTest.java b/src/test/java/ua/net/uid/utils/helpers/StringHelperTest.java
index cbeb630..26b4da7 100644
--- a/src/test/java/ua/net/uid/utils/helpers/StringHelperTest.java
+++ b/src/test/java/ua/net/uid/utils/helpers/StringHelperTest.java
@@ -232,7 +232,11 @@
 
     @Test
     void testIsBlank() {
+        assertTrue(StringHelper.isBlank(null));
+        assertTrue(StringHelper.isBlank(""));
         assertTrue(StringHelper.isBlank(" \t\r\n\u005Ct"));
+        assertFalse(StringHelper.isBlank("a"));
         assertFalse(StringHelper.isBlank(" \t\r\n\u005Ctq"));
+        assertFalse(StringHelper.isBlank(" \t\r\n\0x2F81A"));
     }
 }