Fix #249: emits closing tag without opening tag in SimpleXmlEncoder

Changes `SimpleXmlEncoder` to not emit a closing root tag if no records
were processed. Additionally, the test cases are refactored.

Author: cboehme

src/main/java/org/culturegraph/mf/stream/converter/xml/SimpleXmlEncoder.java

@@ -164,7 +164,9 @@ protected void onResetStream() {
 	@Override
 	protected void onCloseStream() {
 		if (!separateRoots) {
-			writeFooter();
+			if (!atStreamStart) {
+				writeFooter();
+			}
 			sendAndClearData();
 		}
 	}

src/test/java/org/culturegraph/mf/stream/converter/xml/SimpleXmlEncoderTest.java

@@ -17,88 +17,91 @@
 
 
 
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
 import org.culturegraph.mf.framework.DefaultObjectReceiver;
-import org.culturegraph.mf.framework.StreamReceiver;
-import org.culturegraph.mf.stream.converter.xml.SimpleXmlEncoder;
-import org.junit.Assert;
+import org.junit.Before;
 import org.junit.Test;
 
 /**
- * Tests {@link SimpleXmlEncoder}.
+ * Tests for class {@link SimpleXmlEncoder}.
  *
  * @author Markus Geipel
+ * @author Christoph Böhme
  *
  */
 public final class SimpleXmlEncoderTest {
 
-
 	private static final String TAG = "tag";
 	private static final String VALUE = "value";
 
-	//TODO add more tests!
+	private SimpleXmlEncoder simpleXmlEncoder;
+
+	private StringBuilder resultCollector;
+
+	@Before
+	public void initSystemUnderTest() {
+		simpleXmlEncoder = new SimpleXmlEncoder();
+		simpleXmlEncoder.setReceiver(
+				new DefaultObjectReceiver<String>() {
+					@Override
+					public void process(final String obj) {
+						resultCollector.append(obj);
+					}
+				});
+		resultCollector = new StringBuilder();
+}
 
+	@Test
+	public void issue249_shouldNotEmitClosingRootTagOnCloseStreamIfNoOutputWasGenerated() {
+		simpleXmlEncoder.closeStream();
+
+		assertTrue(getResultXml().isEmpty());
+	}
 
 	@Test
-	public void testShouldOnlyEscapeFiveChars() {
+	public void shouldOnlyEscapeXmlReservedCharacters() {
 		final StringBuilder builder = new StringBuilder();
 
 		SimpleXmlEncoder.writeEscaped(builder , "&<>'\" üäö");
 
-		Assert.assertEquals("&amp;&lt;&gt;&apos;&quot; üäö", builder.toString());
+		assertEquals("&amp;&lt;&gt;&apos;&quot; üäö", builder.toString());
 	}
 
 	@Test
-	public void testShouldHandleSeparateRoots(){
-		final SimpleXmlEncoder writer = new SimpleXmlEncoder();
-		writer.setRootTag("root");
-		writer.setRecordTag("record");
-		writer.setWriteXmlHeader(false);
-
-		//separateRoots=false
-		final StringBuilder builder1 = new StringBuilder();
-		writer.setReceiver(new DefaultObjectReceiver<String>() {
-			@Override
-			public void process(final String obj) {
-				builder1.append(obj);
-			}
-		});
-
-		writer.setSeparateRoots(false);
+	public void shouldWrapEachRecordInRootTagIfSeparateRootsIsTrue() {
+		simpleXmlEncoder.setSeparateRoots(true);
 
+		emitTwoRecords();
 
-		writeTwoRecords(writer);
-
-		Assert.assertEquals("<root><record><tag>value</tag></record><record><tag>value</tag></record></root>", builder1.toString().replaceAll("[\\n\\s]", ""));
-
-		//separateRoots=true
-		final StringBuilder builder2 = new StringBuilder();
-		writer.setReceiver(new DefaultObjectReceiver<String>() {
-			@Override
-			public void process(final String obj) {
-				builder2.append(obj);
-			}
-		});
-
-		writer.setSeparateRoots(true);
-
-		writeTwoRecords(writer);
+		assertEquals("<?xml version=\"1.0\" encoding=\"UTF-8\"?><records><record><tag>value</tag></record></records><?xml version=\"1.0\" encoding=\"UTF-8\"?><records><record><tag>value</tag></record></records>",
+				getResultXml());
+	}
 
-		Assert.assertEquals("<root><record><tag>value</tag></record></root><root><record><tag>value</tag></record></root>", builder2.toString().replaceAll("[\\n\\s]", ""));
+	@Test
+	public void shouldWrapAllRecordsInOneRootTagtIfSeparateRootsIsFalse() {
+		simpleXmlEncoder.setSeparateRoots(false);
 
+		emitTwoRecords();
 
+		assertEquals("<?xml version=\"1.0\" encoding=\"UTF-8\"?><records><record><tag>value</tag></record><record><tag>value</tag></record></records>",
+				getResultXml());
 	}
 
-
-
-	private static void writeTwoRecords(final StreamReceiver writer) {
-		writer.startRecord("X");
-		writer.literal(TAG, VALUE);
-		writer.endRecord();
-		writer.startRecord("Y");
-		writer.literal(TAG, VALUE);
-		writer.endRecord();
-		writer.closeStream();
+	private void emitTwoRecords() {
+		simpleXmlEncoder.startRecord("X");
+		simpleXmlEncoder.literal(TAG, VALUE);
+		simpleXmlEncoder.endRecord();
+		simpleXmlEncoder.startRecord("Y");
+		simpleXmlEncoder.literal(TAG, VALUE);
+		simpleXmlEncoder.endRecord();
+		simpleXmlEncoder.closeStream();
 	}
 
+	private String getResultXml() {
+		return resultCollector.toString().replaceAll("[\\n\\t]", "");
+	}
 
 }