diff --git a/core-java-modules/core-java-numbers-8/src/test/java/com/baeldung/sumofnevendivisibleby3/SumOfNFirstEvenNumbersDivisibleBy3UnitTest.java b/core-java-modules/core-java-numbers-8/src/test/java/com/baeldung/sumofnevendivisibleby3/SumOfNFirstEvenNumbersDivisibleBy3UnitTest.java
new file mode 100644
index 000000000000..45b8005f3fad
--- /dev/null
+++ b/core-java-modules/core-java-numbers-8/src/test/java/com/baeldung/sumofnevendivisibleby3/SumOfNFirstEvenNumbersDivisibleBy3UnitTest.java
@@ -0,0 +1,54 @@
+package com.baeldung.sumofnevendivisibleby3;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.stream.IntStream;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class SumOfNFirstEvenNumbersDivisibleBy3UnitTest {
+
+    private static final int NUMBER = 7;
+    private static final int EXPECTED_SUM = 18;
+
+    @Test
+    void givenN_whenUsingBruteForceForLoop_thenReturnsCorrectSum() {
+        int sum = 0;
+
+        for (int i = 2; i <= NUMBER * 2; i++) {
+            if (i % 2 == 0 && i % 3 == 0) {
+                sum += i;
+            }
+        }
+
+        assertEquals(EXPECTED_SUM, sum);
+    }
+
+    @Test
+    void givenN_whenUsingFunctionalApproach_thenReturnsCorrectSum() {
+        int sum = IntStream.iterate(2, i -> i + 1)
+          .filter(i -> i % 2 == 0)
+          .limit(NUMBER)
+          .filter(i -> i % 3 == 0)
+          .sum();
+
+        assertEquals(EXPECTED_SUM, sum);
+    }
+
+    @Test
+    void givenN_whenUsingImprovedBruteForce_thenReturnsCorrectSum() {
+        int sum = IntStream.iterate(6, i -> i + 6)
+          .limit(NUMBER / 3)
+          .sum();
+
+        assertEquals(EXPECTED_SUM, sum);
+    }
+
+    @Test
+    void givenN_whenUsingOptimizedMethod_thenReturnsCorrectSum() {
+        int sum = 3 * (NUMBER / 3) * (NUMBER / 3 + 1);
+
+        assertEquals(EXPECTED_SUM, sum);
+    }
+
+}