@Test
public void removeAll() throws Exception {

    multiMap.putAll("first", ImmutableList.of(
            new TestEntity("1", "v1"),
            new TestEntity("2", "v2")
    ));
    assertThat(multiMap.containsKey("first")).isTrue();
    assertThat(multiMap.removeAll("first")).hasSize(2).containsExactly(
            new TestEntity("1", "v1"),
            new TestEntity("2", "v2")
    );
    assertThat(multiMap.containsKey("first")).isFalse();
}