diff --git a/src/test/java/com/baidu/hugegraph/unit/util/UnitUtilTest.java b/src/test/java/com/baidu/hugegraph/unit/util/UnitUtilTest.java
index f7103190..d857f3a5 100644
--- a/src/test/java/com/baidu/hugegraph/unit/util/UnitUtilTest.java
+++ b/src/test/java/com/baidu/hugegraph/unit/util/UnitUtilTest.java
@@ -132,7 +132,7 @@ public void testBytesToGB() {
         value = UnitUtil.bytesToGB(Bytes.GB * 7357924680L);
         Assert.assertEquals(7357924680d, value, 0d);
 
-        // overflow
+        // Bytes overflow long value
         value = UnitUtil.bytesToGB(Bytes.GB * 9357924680L);
         Assert.assertEquals(-7.821944504E9, value, 0d);
     }
@@ -337,7 +337,7 @@ public void testBytesToReadableString() {
                                                (long) (755 * 1.024) * Bytes.PB);
         Assert.assertEquals("7.75 EB", value);
 
-        // overflow
+        // Bytes overflow long value
         value = UnitUtil.bytesToReadableString(Bytes.EB * 8);
         Assert.assertEquals("0 B", value);
     }
@@ -509,7 +509,7 @@ public void testBytesFromReadableStringWithInvalidFormat() {
                                   e.getMessage());
         });
 
-        // overflow
+        // Bytes overflow long value
         Assert.assertThrows(IllegalArgumentException.class, () -> {
             UnitUtil.bytesFromReadableString("8.1 EIB");
         }, e -> {