new Builder<String, Integer>().put(Maps.immutableEntry("one", 1)).build();
    assertEquals(Arrays.asList(1), multimap.get("one"));
  }

  public void testBuilder_withImmutableEntryAndNullContents() {
    Builder<String, Integer> builder = new Builder<>();
    assertThrows(
        NullPointerException.class, () -> builder.put(Maps.immutableEntry("one", (Integer) null)));
    assertThrows(

        new Builder<String, Integer>().put(Maps.immutableEntry("one", 1)).build();
    assertEquals(Arrays.asList(1), multimap.get("one"));
  }

  public void testBuilder_withImmutableEntryAndNullContents() {
    Builder<String, Integer> builder = new Builder<>();
    assertThrows(
        NullPointerException.class, () -> builder.put(Maps.immutableEntry("one", (Integer) null)));
    assertThrows(

        new Builder<String, Integer>().put(Maps.immutableEntry("one", 1)).build();
    assertEquals(ImmutableSet.of(1), multimap.get("one"));
  }

  public void testBuilder_withImmutableEntryAndNullContents() {
    Builder<String, Integer> builder = new Builder<>();
    assertThrows(
        NullPointerException.class, () -> builder.put(Maps.immutableEntry("one", (Integer) null)));
    assertThrows(

    ImmutableMap<String, Integer> map =
        new Builder<String, Integer>().put(immutableEntry("one", 1)).buildOrThrow();
    assertMapEquals(map, "one", 1);
  }

  public void testBuilder_withImmutableEntryAndNullContents() {
    Builder<String, Integer> builder = new Builder<>();
    assertThrows(
        NullPointerException.class, () -> builder.put(immutableEntry("one", (Integer) null)));