String getBuildVersion() {
        return getManifestAttribute("Implementation-Version", "<version_unknown>");
    }
@Test
    public void testRequestedManifestIsLocatedAndLoaded() throws Exception {
        DiscoveryBuildInfo buildInfo = new DiscoveryBuildInfo(ObjectMapper.class);
        assertThat(buildInfo.getBuildVersion().contains("version_unknown"), is(false));
    }