BAEL-2934 IntStreams conversions

(cherry picked from commit 11abb325ecb2f299c318d82952e7718bab03510c)

java-streams/src/test/java/com/baeldung/intstreams/conversion/IntStreamsConversionsUnitTest.java

@@ -0,0 +1,40 @@
+package com.baeldung.intstreams.conversion;
+
+import org.junit.Test;
+
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class IntStreamsConversionsUnitTest {
+
+    @Test
+    public void intStreamToArray() {
+        int[] first50EvenNumbers = IntStream.iterate(0, i -> i + 2)
+                .limit(50)
+                .toArray();
+
+        assertThat(first50EvenNumbers).hasSize(50);
+        assertThat(first50EvenNumbers[2]).isEqualTo(4);
+    }
+
+    @Test
+    public void intStreamToList() {
+        List<Integer> first50IntegerNumbers = IntStream.range(0, 50)
+                .boxed()
+                .collect(Collectors.toList());
+
+        assertThat(first50IntegerNumbers).hasSize(50);
+        assertThat(first50IntegerNumbers.get(2)).isEqualTo(2);
+    }
+
+    @Test
+    public void intStreamToString() {
+        String first3numbers = IntStream.range(0, 3)
+                .mapToObj(String::valueOf)
+                .collect(Collectors.joining(", ", "[", "]"));
+
+        assertThat(first3numbers).isEqualTo("[0, 1, 2]");
+    }
+}