diff --git a/plusone-commons/src/test/java/xyz/zhouxy/plusone/commons/util/NumbersTests.java b/plusone-commons/src/test/java/xyz/zhouxy/plusone/commons/util/NumbersTests.java
index 453daab..a56592a 100644
--- a/plusone-commons/src/test/java/xyz/zhouxy/plusone/commons/util/NumbersTests.java
+++ b/plusone-commons/src/test/java/xyz/zhouxy/plusone/commons/util/NumbersTests.java
@@ -69,9 +69,16 @@ class NumbersTests {
 
     @Test
     public void sum_BigIntegerArray_ReturnsCorrectSum() {
-        BigInteger[] numbers = {new BigInteger("1"), new BigInteger("2"), new BigInteger("3")};
+        BigInteger[] numbers = {
+            new BigInteger("1"),
+            new BigInteger("2"),
+            null,
+            new BigInteger("3")
+        };
         BigInteger result = Numbers.sum(numbers);
         assertEquals(new BigInteger("6"), result);
+
+        assertEquals(BigInteger.ZERO, Numbers.sum(new BigInteger[0]));
     }
 
     @Test