TestRepository: Ignore existing Change-Id in message

Change-Id: I343c3065fa369ef8aab2b033ac1e392b28d10daf

org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/TestRepository.java

@@ -1045,6 +1045,10 @@ public class TestRepository<R extends Repository> {
 
 		private void insertChangeId(org.eclipse.jgit.lib.CommitBuilder c)
 				throws IOException {
+			int idx = ChangeIdUtil.indexOfChangeId(message, "\n");
+			if (idx >= 0)
+				return;
+
 			ObjectId firstParentId = null;
 			if (!parents.isEmpty())
 				firstParentId = parents.get(0);

org.eclipse.jgit.test/tst/org/eclipse/jgit/junit/TestRepositoryTest.java

@@ -102,6 +102,16 @@ public class TestRepositoryTest {
 				c2.getFullMessage());
 	}
 
+	@Test
+	public void insertChangeIdIgnoresExisting() throws Exception {
+		String msg = "message\n"
+				+ "\n"
+				+	"Change-Id: Ideadbeefdeadbeefdeadbeefdeadbeefdeadbeef\n";
+		RevCommit c = tr.commit().message(msg).insertChangeId().create();
+		rw.parseBody(c);
+		assertEquals(msg, c.getFullMessage());
+	}
+
 	@Test
 	public void resetFromSymref() throws Exception {
 		repo.updateRef("HEAD").link("refs/heads/master");