BAEL-581 Convert Iterable to Stream

core-java/src/test/java/com/baeldung/java/conversion/IterableStreamConversionTest.java

@@ -0,0 +1,44 @@
+package com.baeldung.java.conversion;
+
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class IterableStreamConversionTest {
+
+    @Test
+    public void givenIterable_whenConvertedToStream_thenTrue() {
+        String[] names = { "Testing", "Iterable", "conversion", "to", "Stream" };
+        StreamIterable<String> iterable = new StreamIterable<>(names);
+        Assert.assertTrue(StreamSupport.stream(iterable.spliterator(), false) instanceof Stream<?>);
+    }
+
+    @Test
+    public void whenConvertedToList_thenCorrect() {
+        String[] names = { "Testing", "Iterable", "conversion", "to", "Stream" };
+        StreamIterable<String> iterable = new StreamIterable<>(names);
+        Stream<String> convertedStream = StreamSupport.stream(iterable.spliterator(), false);
+        Assert.assertTrue(convertedStream.map(String::toUpperCase)
+            .collect(Collectors.toList()) instanceof List<?>);
+    }
+}
+
+class StreamIterable<T> implements Iterable<T> {
+    private List<T> list;
+
+    public StreamIterable(T[] array) {
+        this.list = Arrays.asList(array);
+    }
+
+    @Override
+    public Iterator<T> iterator() {
+        return list.iterator();
+    }
+
+}