### Question:
StoreSamplerBuilder { public Sampler<Store> build() { Sampler<Integer> idSampler = new SequenceSampler(); ProbabilityDensityFunction<Location> locationPopulationPDF = new StoreLocationPopulationPDF(zipcodeTable); ProbabilityDensityFunction<Location> locationIncomePDF = new StoreLocationIncomePDF(zipcodeTable, Constants.INCOME_SCALING_FACTOR); ProbabilityDensityFunction<Location> locationJointPDF = new JointPDF<Location>(zipcodeTable, locationPopulationPDF, locationIncomePDF); Sampler<Location> locationSampler = RouletteWheelSampler.create(zipcodeTable, locationJointPDF, seedFactory); return new StoreSampler(idSampler, locationSampler); } StoreSamplerBuilder(List<Location> zipcodeTable, SeedFactory seedFactory); Sampler<Store> build();  }### Answer:
@Test public void testBuild() throws Exception { List<Location> zipcodes = Arrays.asList(new Location[] { new Location("11111", Pair.of(1.0, 1.0), "AZ", "Tempte", 30000.0, 100), new Location("22222", Pair.of(2.0, 2.0), "AZ", "Phoenix", 45000.0, 200), new Location("33333", Pair.of(3.0, 3.0), "AZ", "Flagstaff", 60000.0, 300) }); assertTrue(zipcodes.size() > 0); SeedFactory factory = new SeedFactory(1234); StoreSamplerBuilder builder = new StoreSamplerBuilder(zipcodes, factory); Sampler<Store> sampler = builder.build(); Store store = sampler.sample(); assertNotNull(store); assertTrue(store.getId() >= 0); assertNotNull(store.getName()); assertNotNull(store.getLocation()); }