@Test
public void testPartitionExpression() {

    Assert.assertEquals(FeedHelper.normalizePartitionExpression(" /a// ", "  /b// "), "a/b");
    Assert.assertEquals(FeedHelper.normalizePartitionExpression(null, "  /b// "), "b");
    Assert.assertEquals(FeedHelper.normalizePartitionExpression(null, null), "");
}