@Test
public void testResolveSigningKey() throws Exception {

    // mocks
    KeyStore keyStoreMock = Mockito.spy(baseKeyStore);
    SigningKeyResolver jwksResolverMock = Mockito.spy(basejwksResolver);
    // instance
    KeyStoreJwkKeyResolver resolver = new KeyStoreJwkKeyResolver(null, "file:///", null);
    Field keyStoreField = resolver.getClass().getDeclaredField("keyStore");
    keyStoreField.setAccessible(true);
    Field providerField = resolver.getClass().getDeclaredField("jwksResolver");
    providerField.setAccessible(true);
    providerField.set(resolver, jwksResolverMock);
    // args
    DefaultJwsHeader jwsHeader = new DefaultJwsHeader();
    DefaultClaims claims = new DefaultClaims();
    // 1. null key store, find in JWKS
    PublicKey pk11 = Mockito.spy(basePublicKey);
    Mockito.when(jwksResolverMock.resolveSigningKey(jwsHeader, claims)).thenReturn(pk11);
    jwsHeader.setKeyId("11");
    claims.setIssuer(null);
    assertSame(resolver.resolveSigningKey(jwsHeader, claims), pk11);
    // set key store mock
    keyStoreField.set(resolver, keyStoreMock);
    // 2. invalid issuer, find in JWKS
    PublicKey pk21 = Mockito.spy(basePublicKey);
    Mockito.when(jwksResolverMock.resolveSigningKey(jwsHeader, claims)).thenReturn(pk21);
    jwsHeader.setKeyId("21");
    claims.setIssuer(null);
    assertSame(resolver.resolveSigningKey(jwsHeader, claims), pk21);
    PublicKey pk22 = Mockito.spy(basePublicKey);
    Mockito.when(jwksResolverMock.resolveSigningKey(jwsHeader, claims)).thenReturn(pk22);
    jwsHeader.setKeyId("22");
    claims.setIssuer("");
    assertSame(resolver.resolveSigningKey(jwsHeader, claims), pk22);
    PublicKey pk23 = Mockito.spy(basePublicKey);
    Mockito.when(jwksResolverMock.resolveSigningKey(jwsHeader, claims)).thenReturn(pk23);
    jwsHeader.setKeyId("23");
    claims.setIssuer("domain23-----service23");
    assertSame(resolver.resolveSigningKey(jwsHeader, claims), pk23);
    // 2. invalid domain, find in JWKS
    PublicKey pk24 = Mockito.spy(basePublicKey);
    Mockito.when(jwksResolverMock.resolveSigningKey(jwsHeader, claims)).thenReturn(pk24);
    jwsHeader.setKeyId("24");
    claims.setIssuer("domain24.service24");
    assertSame(resolver.resolveSigningKey(jwsHeader, claims), pk24);
    // 3. found in key store, skip JWKS
    PublicKey pk31 = null;
    try (PemReader reader = new PemReader(new FileReader(this.classLoader.getResource("jwt_public.key").getFile()))) {
        pk31 = KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(reader.readPemObject().getContent()));
    }
    Mockito.when(jwksResolverMock.resolveSigningKey(jwsHeader, claims)).thenReturn(pk31);
    Mockito.when(keyStoreMock.getPublicKey("sys.auth", "service31", "31")).thenReturn("-----BEGIN PUBLIC KEY-----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\n17HCydWCF50HI2XojtGgRN0CAwEAAQ==\n-----END PUBLIC KEY-----\n");
    jwsHeader.setKeyId("31");
    claims.setIssuer("sys.auth.service31");
    assertEquals(resolver.resolveSigningKey(jwsHeader, claims), pk31);
    // 3. NOT found in key store, find in JWKS
    PublicKey pk32 = Mockito.spy(basePublicKey);
    Mockito.when(jwksResolverMock.resolveSigningKey(jwsHeader, claims)).thenReturn(pk32);
    Mockito.when(keyStoreMock.getPublicKey("sys.auth", "service32", "32")).thenReturn(null);
    jwsHeader.setKeyId("32");
    claims.setIssuer("sys.auth.service32");
    assertSame(resolver.resolveSigningKey(jwsHeader, claims), pk32);
    // 3. found in key store but public key invalid, find in JWKS
    PublicKey pk33 = Mockito.spy(basePublicKey);
    Mockito.when(jwksResolverMock.resolveSigningKey(jwsHeader, claims)).thenReturn(pk33);
    Mockito.when(keyStoreMock.getPublicKey("sys.auth", "service33", "33")).thenReturn("");
    jwsHeader.setKeyId("33");
    claims.setIssuer("sys.auth.service33");
    assertSame(resolver.resolveSigningKey(jwsHeader, claims), pk33);
    PublicKey pk34 = Mockito.spy(basePublicKey);
    Mockito.when(jwksResolverMock.resolveSigningKey(jwsHeader, claims)).thenReturn(pk34);
    Mockito.when(keyStoreMock.getPublicKey("sys.auth", "service34", "34")).thenReturn("-----BEGIN PUBLIC KEY-----\ninvalid\n-----END PUBLIC KEY-----\n");
    jwsHeader.setKeyId("34");
    claims.setIssuer("sys.auth.service34");
    assertSame(resolver.resolveSigningKey(jwsHeader, claims), pk34);
    // 4. both NOT found
    jwsHeader.setKeyId("41");
    claims.setIssuer("sys.auth.service41");
    Mockito.when(jwksResolverMock.resolveSigningKey(jwsHeader, claims)).thenReturn(null);
    Mockito.when(keyStoreMock.getPublicKey("sys.auth", "service41", "41")).thenReturn(null);
    assertNull(resolver.resolveSigningKey(jwsHeader, claims));
    // 5. skip, empty key ID
    jwsHeader.setKeyId(null);
    claims.setIssuer(null);
    assertNull(resolver.resolveSigningKey(jwsHeader, claims));
    jwsHeader.setKeyId("");
    claims.setIssuer(null);
    assertNull(resolver.resolveSigningKey(jwsHeader, claims));
}