[BAEL-3348] Moved code to algorithm-4

java-numbers/src/test/java/com/baeldung/pairsaddupnumber/ExistingPairsUnitTest.java

@@ -0,0 +1,34 @@
+package com.baeldung.pairsaddupnumber;
+
+import org.junit.Test;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+
+public class ExistingPairsUnitTest {
+
+    /* All existing pairs */
+
+    @Test
+    public void whenTraditionalLoop_thenReturnAllExistingPairs() {
+        /* Data */
+        final int[] input = {2, 4, 3, 3, 8};
+        final int sum = 6;
+        /* Call service */
+        final List<Integer> pairs = ExistingPairs.findPairsWithForLoop(input, sum);
+        /* Check results */
+        assertThat(pairs).hasSize(4).contains(2,4,3,3).doesNotContain(8);
+    }
+
+    @Test
+    public void whenStreamApi_thenReturnAllExistingPairs() {
+        /* Data */
+        final int[] input = {2, 4, 3, 3, 8};
+        final int sum = 6;
+        /* Call service */
+        final List<Integer> pairs = ExistingPairs.findPairsWithStreamApi(input, sum);
+        /* Check results */
+        assertThat(pairs).hasSize(4).contains(2,4,3,3).doesNotContain(8);
+    }
+}