### Question:
FrequencyMeasurement extends BasicMeasurement { public Integer getFrequency(String category) throws IllegalArgumentException { checkCategory(category); return getFrequencies().get(category); } private  FrequencyMeasurement();  FrequencyMeasurement(PopulationCharacteristic cv);  FrequencyMeasurement(List<String> categories, Map<String, Integer> map); void setFrequency(String category, Integer freq); Integer getFrequency(String category); String[] getCategories(); void add(FrequencyMeasurement other); boolean isOfType(VariableType type); @Override Set<Entity> getDependencies(); @Override String toString(); @Override FrequencyMeasurement clone(); @Override boolean equals(Object o); @Override int hashCode(); static final String PROPERTY_FREQUENCIES; }### Answer:
@Test(expected=IllegalArgumentException.class) public void testGetFrequencyThrows() { d_meas.getFrequency("illegalCat"); }