### Question:
ObjectContextChangeLog { GraphDiff getDiffs() { return new CompoundDiff(immutableList(0, diffs.size())); } ObjectContextChangeLog();   }### Answer:
@Test public void testGetDiffs() { ObjectContextChangeLog recorder = new ObjectContextChangeLog(); recorder.addOperation(new NodeCreateOperation(new Object())); CompoundDiff diff = (CompoundDiff) recorder.getDiffs(); assertEquals(1, diff.getDiffs().size()); recorder.addOperation(new NodeCreateOperation(new Object())); assertEquals(1, diff.getDiffs().size()); CompoundDiff diff2 = (CompoundDiff) recorder.getDiffs(); assertEquals(2, diff2.getDiffs().size()); }