Don't close IonParser on EOF to be compatible with MappingIterator when source is an empty InputStream (#487)

Author: yvrng

ion/src/main/java/com/fasterxml/jackson/dataformat/ion/IonParser.java

@@ -676,7 +676,6 @@ public JsonToken nextToken() throws IOException
         }
         if (type == null) {
             if (_parsingContext.inRoot()) { // EOF?
-                close();
                 _currToken = null;
             } else {
                 _parsingContext = _parsingContext.getParent();

ion/src/test/java/com/fasterxml/jackson/dataformat/ion/sequence/MappingIteratorTest.java

@@ -0,0 +1,50 @@
+package com.fasterxml.jackson.dataformat.ion.sequence;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import com.fasterxml.jackson.databind.MappingIterator;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SequenceWriter;
+import com.fasterxml.jackson.dataformat.ion.IonObjectMapper;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import org.junit.Test;
+
+public class MappingIteratorTest {
+
+    private static final ObjectMapper MAPPER = new IonObjectMapper();
+
+    @Test
+    public void testReadFromWrite() throws Exception {
+        final Object[] values = new String[]{"1", "2", "3", "4"};
+
+        // write
+        final ByteArrayOutputStream out = new ByteArrayOutputStream();
+        try (SequenceWriter seq = MAPPER.writer().writeValues(out)) {
+            for (Object value : values) {
+                seq.write(value);
+            }
+        }
+
+        // read
+        final ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());
+        try (MappingIterator<Object> it = MAPPER.readerFor(Object.class).readValues(in)) {
+            for (Object value : values) {
+                assertTrue(it.hasNext());
+                assertTrue(it.hasNext()); // should not alter the iterator state
+                assertEquals(value, it.next());
+            }
+            assertFalse(it.hasNext());
+        }
+    }
+
+    @Test
+    public void testReadFromEmpty() throws Exception {
+        final ByteArrayInputStream in = new ByteArrayInputStream(new byte[0]);
+        try (MappingIterator<Object> it = MAPPER.readerFor(Object.class).readValues(in)) {
+            assertFalse(it.hasNext());
+        }
+    }
+}