writeSymref(Constants.HEAD, "refs/heads/prefix/a");
RefUpdate updateRef = db.updateRef("refs/heads/prefix/a");
updateRef.setNewObjectId(rb);
updateRef.setRefLogMessage("Setup", false);
updateRef.setForceUpdate(true);
assertEquals(Result.FORCED, updateRef.update());
ObjectId oldHead = db.resolve(Constants.HEAD);
assertEquals(oldHead, rb); // assumption for this test
writeReflog(db, rb, "Just a message", "refs/heads/prefix/a");
assertTrue("internal check, we have a log", new File(db.getDirectory(),
"logs/refs/heads/prefix/a").exists());