@Test
public void testPowerSetOfThreeElementsHasCorrectSubsets() {
LongSet<Set<String>> powerSet =
LongPowerSet.create(new HashSet<>(Arrays.asList("a", "b", "c")));
assertEquals("expect 8 subsets in the power set of a 3 element set", 8, powerSet.longSize());
Set<Set<String>> constructedSet = new HashSet<>();
for (Set<String> subset : powerSet) {
constructedSet.add(subset);
}
Set<String> emptySet = Collections.emptySet();
Set<String> singleElementSet1 = Collections.singleton("a");
Set<String> singleElementSet2 = Collections.singleton("b");
Set<String> singleElementSet3 = Collections.singleton("c");
Set<String> twoElementSet1 = new HashSet<>(Arrays.asList("a", "b"));
Set<String> twoElementSet2 = new HashSet<>(Arrays.asList("a", "c"));
Set<String> twoElementSet3 = new HashSet<>(Arrays.asList("b", "c"));
Set<String> threeElementSet = new HashSet<>(Arrays.asList("a", "b", "c"));
Set<Set<String>> expectedSet =
new HashSet<>(
Arrays.asList(
emptySet,
singleElementSet1,
singleElementSet2,
singleElementSet3,
twoElementSet1,
twoElementSet2,
twoElementSet3,
threeElementSet));
assertEquals(
"expect iterated contents of power set to be correct", expectedSet, constructedSet);
assertTrue("expect power set to contain correct subsets", powerSet.containsAll(expectedSet));
}
@Test
public void testEmptyPowerSetHasOneEmptySubset() {
LongSet<Set<String>> powerSet = LongPowerSet.create(new HashSet<>());
assertEquals(
"expect one empty subset in the power set of the empty set", 1, powerSet.longSize());
assertFalse("expect power set of the empty set to be non-empty", powerSet.isEmpty());
assertEquals(
"expect one empty subset in the power set of the empty set",
0,
powerSet.iterator().next().size());
assertTrue(
"expect power set of the empty set contains the empty set",
powerSet.contains(Collections.emptySet()));
assertEquals(
"expect empty power sets to be equal", LongPowerSet.create(new HashSet<>()), powerSet);
Set<Set<String>> constructedSet = new HashSet<>();
for (Set<String> subset : powerSet) {
constructedSet.add(subset);
}
Set<String> emptySet = Collections.emptySet();
Set<Set<String>> expectedSet = new HashSet<>(Arrays.asList(emptySet));
assertEquals(
"expect iterated contents of power set to be correct", expectedSet, constructedSet);
}
@Test
public void testPowerSetOfSingleElementHasCorrectSubsets() {
LongSet<Set<String>> powerSet = LongPowerSet.create(new HashSet<>(Arrays.asList("a")));
assertEquals(
"expect one empty subset and one one element subset in the power set of a single element set",
2,
powerSet.longSize());
assertTrue(
"expect empty subset to be contained in power set of single element set",
powerSet.contains(Collections.emptySet()));
assertTrue(
"expect single element subset to be contained in power set of single element set",
powerSet.contains(new HashSet<>(Arrays.asList("a"))));
Set<Set<String>> constructedSet = new HashSet<>();
for (Set<String> subset : powerSet) {
constructedSet.add(subset);
}
Set<String> emptySet = Collections.emptySet();
Set<String> singleElementSet = Collections.singleton("a");
Set<Set<String>> expectedSet = new HashSet<>(Arrays.asList(emptySet, singleElementSet));
assertEquals(
"expect iterated contents of power set to be correct", expectedSet, constructedSet);
}
