Make a SimpleJobIdentifierFactory for SimpleJobIdentifiers

OPEN - issue BATCH-58: Make JobStream and JobRun optional properties of Job (e.g. through join to optional table) 
http://opensource.atlassian.com/projects/spring/browse/BATCH-58

core/src/test/java/org/springframework/batch/core/runtime/SimpleJobIdentifierFactoryTests.java

@@ -0,0 +1,12 @@
+package org.springframework.batch.core.runtime;
+
+import junit.framework.TestCase;
+
+public class SimpleJobIdentifierFactoryTests extends TestCase {
+
+	public void testGetJobIdentifier() {
+		JobIdentifier jobIdentifier = new SimpleJobIdentifierFactory().getJobIdentifier("foo");
+		assertEquals("foo", jobIdentifier.getName());
+	}
+
+}