public final void hasSize(int expectedSize) {
    checkArgument(expectedSize >= 0, "expectedSize(%s) must be >= 0", expectedSize);
    int actualSize = size(checkNotNull(actual));
    check("size()").that(actualSize).isEqualTo(expectedSize);
  }
@Test
  public void hasSize() {
    assertThat(ImmutableList.of(1, 2, 3)).hasSize(3);
  }