@Test
public void nonZeroElements() {

    VectorStorage storage = createStorage();
    double[] data = storage.data();
    testVector = getAbstractVector(storage);
    assertEquals(MathTestConstants.VAL_NOT_EQUALS, testVector.nonZeroElements(), Arrays.stream(data).filter(x -> x != 0d).count());
    addNilValues(data);
    assertEquals(MathTestConstants.VAL_NOT_EQUALS, testVector.nonZeroElements(), Arrays.stream(data).filter(x -> x != 0d).count());
}