@Test public void injectKindFormats() {

  B3Propagation.Factory factory = (B3Propagation.Factory) B3Propagation.newFactoryBuilder()
    .injectFormats(Span.Kind.CLIENT, Format.SINGLE, Format.MULTI)
    .build();
  assertThat(factory.injectorFactory).extracting("clientInjectorFunction.injectorFunctions")
    .asInstanceOf(InstanceOfAssertFactories.ARRAY)
    .containsExactly(Format.SINGLE, Format.MULTI);
}