public Sdk getSdk(int apiLevel) {
    Sdk sdk = knownSdks.get(apiLevel);
    return sdk == null ? new UnknownSdk(apiLevel) : sdk;
  }
@Test
  public void getSdk_shouldReturnNullObjectForUnknownSdks() throws Exception {
    assertThat(sdkCollection.getSdk(4321)).isNotNull();
    assertThat(sdkCollection.getSdk(4321).isKnown()).isFalse();
  }