diff --git a/algorithms-miscellaneous-4/src/test/java/com/baeldung/algorithms/smallestinteger/SmallestMissingPositiveIntegerUnitTest.java b/algorithms-miscellaneous-4/src/test/java/com/baeldung/algorithms/smallestinteger/SmallestMissingPositiveIntegerUnitTest.java
index 8bb7151b41..a1b1bfaa25 100644
--- a/algorithms-miscellaneous-4/src/test/java/com/baeldung/algorithms/smallestinteger/SmallestMissingPositiveIntegerUnitTest.java
+++ b/algorithms-miscellaneous-4/src/test/java/com/baeldung/algorithms/smallestinteger/SmallestMissingPositiveIntegerUnitTest.java
@@ -85,4 +85,13 @@ class SmallestMissingPositiveIntegerUnitTest {
 
         assertThat(result).isEqualTo(input.length);
     }
+
+    @Test
+    void givenArrayWithoutZero_whenSearchInUnsortedArrayBooleanArray_thenZero() {
+        int[] input = new int[] {11, 13, 14, 15};
+
+        int result = SmallestMissingPositiveInteger.searchInUnsortedArrayBooleanArray(input);
+
+        assertThat(result).isEqualTo(0);
+    }
 }
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