### Question:
CombinationUtil { public static int numberOfSetParameters(int[] combination) { Preconditions.notNull(combination); int numberOfSetParameters = 0; for (int value : combination) { if (value != NO_VALUE) { numberOfSetParameters++; } } return numberOfSetParameters; } private  CombinationUtil(); static int[] emptyCombination(int size); static boolean contains(int[] firstCombination, int[] secondCombination); static boolean canBeAdded(int[] combination, int[] toBeAdded, ConstraintChecker constraintChecker); static void add(int[] combination, int[] toBeAdded); static boolean containsAllParameters(int[] combination, IntSet parameterIndices); static boolean containsAllParameters(int[] combination, int untilParameter); static boolean sameForAllGivenParameters(int[] first, int[] second, IntSet parameters); static int numberOfSetParameters(int[] combination); static final int NO_VALUE; }### Answer:
@Test void numberOfSetParametersPreconditions() { Assertions.assertThrows(NullPointerException.class, () -> CombinationUtil.numberOfSetParameters(null)); }