@Test
public void testVisit() {

    SparseVectorSummarizer summarizer = summarizer();
    Assert.assertEquals(5, summarizer.colNum);
    Assert.assertEquals(5, summarizer.count);
    Assert.assertEquals(5, summarizer.cols.size());
    Assert.assertEquals(10, summarizer.cols.get(0).sum, 10e-6);
    Assert.assertEquals(5, summarizer.cols.get(0).max, 10e-6);
    Assert.assertEquals(1, summarizer.cols.get(0).min, 10e-6);
    Assert.assertEquals(3, summarizer.cols.get(0).numNonZero, 10e-6);
    Assert.assertEquals(10, summarizer.cols.get(0).normL1, 10e-6);
    Assert.assertEquals(42, summarizer.cols.get(0).squareSum, 10e-6);
}