@Test
public void testResolveSigningKeyForJwe() throws MalformedURLException {

    KeyStoreJwkKeyResolver resolver = new KeyStoreJwkKeyResolver(null, "file:///", null);
    assertNull(resolver.resolveSigningKey(null, (String) null));
    assertNull(resolver.resolveSigningKey(null, ""));
    assertNull(resolver.resolveSigningKey(baseJwsHeader, "plaintext"));
}