### Question:
FilterHelper { public static boolean isPK(Filter filter) { return pkFilters.containsAll(filter.getOperations()); } private  FilterHelper(); static boolean isPK(Filter filter);  }### Answer:
@Test public void testPkDistinct() throws Exception { Set pk = new HashSet<>(); pk.add(FILTER_PK_NOT_EQ); FilterHelper.isPK(new Filter(pk, null)); }
@Test public void testPkEQ() throws Exception { Set pk = new HashSet<>(); pk.add(FILTER_PK_EQ); FilterHelper.isPK(new Filter(pk, null)); }
@Test public void testPkGET() throws Exception { Set pk = new HashSet<>(); pk.add(FILTER_PK_GET); FilterHelper.isPK(new Filter(pk, null)); }
@Test public void testPkGT() throws Exception { Set pk = new HashSet<>(); pk.add(FILTER_PK_GT); FilterHelper.isPK(new Filter(pk, null)); }
@Test public void testPkLET() throws Exception { Set pk = new HashSet<>(); pk.add(FILTER_PK_LET); FilterHelper.isPK(new Filter(pk, null)); }
@Test public void testPkLT() throws Exception { Set pk = new HashSet<>(); pk.add(FILTER_PK_LT); FilterHelper.isPK(new Filter(pk, null)); }