@Test
public void no_change() {
AVLTree<String, String> t0 = AVLTree.create();
AVLTree<String, String> t1 = t0.put("1", "1");
assertThat(t1.put("1", "1")).isSameAs(t1);
assertThat(t1.remove("3")).isSameAs(t1);
AVLTree<String, String> t2 = t0.put("2", "2");
assertThat(t2.put("2", "2")).isSameAs(t2);
assertThat(t2.remove("3")).isSameAs(t2);
}
@Test
public void test_replace_root() {
AVLTree<String, String> t0 = AVLTree.create();
AVLTree<String, String> t1 = t0.put("1", "a");
AVLTree<String, String> t2 = t1.put("1", "b");
assertThat(t1).isNotSameAs(t2);
assertThat(t1.get("1")).isEqualTo("a");
assertThat(t2.get("1")).isEqualTo("b");
}
@Test
public void buckets() {
Object k1 = new Key(42, "k1");
Object k2 = new Key(42, "k2");
Object k3 = new Key(42, "k3");
AVLTree<Object, Object> t = AVLTree.create().put(k1, "v1").put(k2, "v2");
assertThat(t.toString()).as("should create bucket").isEqualTo(" k2->v2 k1->v1");
AVLTree<Object, Object> t2 = AVLTree.create().put(k2, "v2").put(k1, "v1");
assertThat(t2.toString())
.as("toString depends on order of operations")
.isEqualTo(" k1->v1 k2->v2");
assertThat(t.equals(t2)).as("should compare buckets").isTrue();
assertThat(t2.equals(t)).as("should compare buckets").isTrue();
assertThat(t.hashCode())
.isEqualTo(
((31 * k1.hashCode()) ^ "v1".hashCode()) + ((31 * k2.hashCode()) ^ "v2".hashCode()));
assertThat(t2.hashCode())
.as("hashCode doesn't depend on order of operations")
.isEqualTo(t.hashCode());
assertThat(t.get(k1)).isEqualTo("v1");
assertThat(t.get(k2)).isEqualTo("v2");
assertThat(t.get(k3)).as("not such key").isNull();
assertThat(t.put(k2, "new v2").toString())
.as("should replace head of bucket")
.isEqualTo(" k2->new v2 k1->v1");
assertThat(t.put(k1, "new v1").toString())
.as("should replace element of bucket")
.isEqualTo(" k1->new v1 k2->v2");
assertThat(t.put(k1, "v1")).as("should not change").isSameAs(t);
assertThat(t.put(k2, "v2")).as("should not change").isSameAs(t);
assertThat(t.put(k3, "v3").toString())
.as("should add to bucket")
.isEqualTo(" k3->v3 k2->v2 k1->v1");
assertThat(t.remove(k2).toString()).as("should remove head of bucket").isEqualTo(" k1->v1");
assertThat(t.remove(k1).toString()).as("should remove element of bucket").isEqualTo(" k2->v2");
assertThat(t.remove(k1).remove(k2).toString()).as("should remove bucket").isEqualTo("");
assertThat(t.remove(k3)).as("should not change").isSameAs(t);
HashMap<Object, Object> biConsumer = new HashMap<>();
t.forEach((k, v) -> assertThat(biConsumer.put(k, v)).as("unique key-value").isNull());
assertThat(biConsumer).isEqualTo(ImmutableMap.of(k1, "v1", k2, "v2"));
HashSet<Object> consumer = new HashSet<>();
t.forEach(k -> assertThat(consumer.add(k)).as("unique key").isTrue());
assertThat(consumer).containsOnly(k1, k2);
}
@Test
public void balancing_should_preserve_buckets() {
Object k1 = new Key(1, "k1");
Object k2 = new Key(2, "k2");
Object k3 = new Key(3, "k3");
Object k4 = new Key(4, "k4");
AVLTree<Object, Object> t = AVLTree.create().put(k1, "v1").put(k2, "v2").put(k3, "v3");
Object k1_1 = new Key(1, "k1_1");
t = t.put(k1_1, "v1_1");
t = t.put(k4, "v4");
assertThat(t.height()).as("height after balancing").isEqualTo(3);
assertThat(t.get(k1_1)).isEqualTo("v1_1");
}
@Test
public void test_one_element() {
AVLTree<String, String> t0 = AVLTree.create();
AVLTree<String, String> t1 = t0.put("1", "a");
AVLTree<String, String> t2 = t0.put("2", "b");
assertThat(t0).isNotSameAs(t1).isNotSameAs(t2);
assertThat(t1).isNotSameAs(t2);
assertThat(t0.get("1")).isNull();
assertThat(t0.get("2")).isNull();
assertThat(t0.get("3")).isNull();
assertThat(t1.get("1")).isEqualTo("a");
assertThat(t1.get("2")).isNull();
assertThat(t2.get("3")).isNull();
assertThat(t2.get("1")).isNull();
assertThat(t2.get("2")).isEqualTo("b");
assertThat(t2.get("3")).isNull();
}