Real method getting called when Mockito doNothing method is called

Question

I am trying to mock the class KeyStore. After mocking I do not want anything to happen when the load method if it has been called. Therefore I wrote the below lines to achieve this.

        @PrepareForTest(KeyStoreFactory.class)
        @Test
        public void should_verify_signature_when_verifySignature_called_with_fileName_and_certificate_details_in_verifySignature_method() throws Exception {
            PowerMockito.mockStatic(KeyStoreFactory.class);

            KeyStore keyStoreMock = PowerMockito.mock(KeyStore.class);
            PowerMockito.when(KeyStoreFactory.getInstance(anyString(), anyString())).thenReturn(keyStoreMock);
            Mockito.doNothing().when(keyStoreMock).load(Mockito.any(InputStream.class), Mockito.any(char[].class));
            Certificate certificateMock = Mockito.mock(Certificate.class);
            when(keyStoreMock.getCertificate(anyString())).thenReturn(certificateMock);
            boolean result = signatureUtil.verifySignature("src//test//java//Updates.zip.signed.pkcs7"
                    , "src//test//java//Updates-retrieved.zip", "Windows-MY,SunMSCAPI,someName");
            Assert.assertTrue(result);

        }

But the load method was throwing null pointer exception. Then when I debug I found out that the real method is getting called though I have specified for mockito to not to. What am I doing wrong here? Please advice.

Below is the method for which I'm writing the test.

    @Override
        public boolean verifySignature(String filePath, String extractContentsPath, String csvParams)
                throws ServiceSDKException {
            boolean result = false;
            String typeOfCertificateStore = "";
            String certificateStoreProvider = "";
            String certificateName = "";
            SignerInformationVerifier verifier = null;
            if (filePath != null && extractContentsPath != null && csvParams != null && !filePath.isEmpty()
                    && !extractContentsPath.isEmpty() && !csvParams.isEmpty()) {

                try {
                    String[] receivedParams = csvParams.split(",");
                    typeOfCertificateStore = receivedParams[0];
                    certificateStoreProvider = receivedParams[1];
                    certificateName = receivedParams[2];
                } catch (ArrayIndexOutOfBoundsException e) {
                    throw new ServiceSDKException("csvParams should have type of certificate store, certificate store provider and certificate name respectively", e);
                }

                try {
                    Path signedDataFilePath = Paths.get(filePath);
                    Path pathToExtractContents = Paths.get(extractContentsPath);

                    KeyStore msCertStore = KeyStoreFactory.getInstance(typeOfCertificateStore, certificateStoreProvider);
                    msCertStore.load(null, null);
                    try {
                        verifier = new JcaSimpleSignerInfoVerifierBuilder()
                                .setProvider(certificateStoreProvider)
                                .build(((X509Certificate) msCertStore.getCertificate(certificateName)));
                    } catch (Exception e) {
                        throw new ServiceSDKException("Exception occurred when building certificate",e);
                    }
                    verify(signedDataFilePath, pathToExtractContents, verifier);
                    result = true;
                } catch (IOException | NoSuchAlgorithmException
                        | CertificateException e) {
                    result = false;
                    throw new ServiceSDKException("Exception occurred while preparing to verify signature " , e);
                }
            } else {
                throw new ServiceSDKException("FilePath,extract contents path or csv params cannot be empty or null");
            }
            return result;
        }

This is the entire test class :

@RunWith(PowerMockRunner.class)
public class SignatureUtilImplTest {

    SignatureUtilImpl signatureUtil = new SignatureUtilImpl();

@PrepareForTest({KeyStoreFactory.class, SignatureUtilImpl.class})
    @Test
    public void should_verify_signature_when_verifySignature_called_with_fileName_and_certificate_details_in_verifySignature_method() throws Exception {
        CMSSignedDataParser spMock = PowerMockito.mock(CMSSignedDataParser.class);
        SignerInformationVerifier verifierMock = Mockito.mock(SignerInformationVerifier.class);
        SignatureUtilImpl signatureUtilSpy = Mockito.spy(new SignatureUtilImpl());
        KeyStore keyStoreMock = PowerMockito.mock(KeyStore.class);
        PowerMockito.mockStatic(KeyStoreFactory.class);
        PowerMockito.when(KeyStoreFactory.getInstance(anyString(), anyString())).thenReturn(keyStoreMock);
        SignerInformation signerInformationMock = Mockito.mock(SignerInformation.class);
        Collection<SignerInformation> collection = new ArrayList();
        collection.add(signerInformationMock);

        Mockito.doCallRealMethod().when(signatureUtilSpy).verifySignature("src/test/java/Updates.zip.signed.pkcs7"
                , "src/test/java/Updates-retrieved.zip", "Windows-MY,SunMSCAPI,someName");
        Mockito.doNothing().when(signatureUtilSpy).loadKeyStore();
        Mockito.doReturn(verifierMock).when(signatureUtilSpy).getSignerInformationVerifier(anyString(), anyString());
        Mockito.doReturn(spMock).when(signatureUtilSpy).getDataParser(any(DigestCalculatorProvider.class), any(FileInputStream.class));
        Mockito.doReturn(collection).when(spMock).getSignerInfos().getSigners();
        Mockito.doReturn(true).when(signerInformationMock).verify(verifierMock);
        //PowerMockito.doNothing().when(signatureUtilSpy, "verify", any(Path.class),any(Path.class),any(SignerInformationVerifier.class));

//        PowerMockito.doReturn(true).when(signatureUtilSpy, PowerMockito.method(SignatureUtilImpl.class, "verify",Path.class,Path.class, SignerInformationVerifier.class))
//                .withArguments(any(Path.class),any(Path.class),any(SignerInformationVerifier.class));

        boolean result = signatureUtilSpy.verifySignature("src/test/java/Updates.zip.signed.pkcs7"
                , "src/test/java/Updates-retrieved.zip", "Windows-MY,SunMSCAPI,someName");
        Assert.assertTrue(result);
}

}

Answer 1

I think this can help :

Create another method in SignatureUtil:

public KeyStore loadKeyStore(...){
  KeyStore msCertStore = KeyStoreFactory.getInstance(typeOfCertificateStore,certificateStoreProvider);
  msCertStore.load(null, null);
}

In your test class do it like below.

Mockito.doNothing().when(signatureUtilMock).loadKeyStore(anyString(), anyString());

Here is the code that is working for me

package com.foo;

import java.io.IOException;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;


public class KeyStoreService {
  public KeyStoreService(){

  }

  public void load() throws KeyStoreException, NoSuchAlgorithmException, CertificateException, IOException{
    System.out.println("start");
    KeyStore ks = KeyStore.getInstance("");
    ks.load(null, null);
    System.out.println("end");
 }


}

Test Class

package com.foo.test;

import java.io.IOException;
import java.io.InputStream;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.cert.CertificateException;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Matchers;
import org.mockito.Mockito;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

import com.foo.KeyStoreService;

@PrepareForTest(KeyStoreService.class)
@RunWith(PowerMockRunner.class)
public class TestKeyStore {

    @Test
    public void test1() throws KeyStoreException, NoSuchProviderException, NoSuchAlgorithmException, CertificateException, IOException{
        PowerMockito.mockStatic(KeyStore.class);
        KeyStore keyStoreMock = PowerMockito.mock(KeyStore.class);
        KeyStoreService kss = new KeyStoreService();
        PowerMockito.when(KeyStore.getInstance(Matchers.anyString(), Matchers.anyString())).thenReturn(keyStoreMock);
        Mockito.doNothing().when(keyStoreMock).load(Mockito.any(InputStream.class), Mockito.any(char[].class));
        kss.load();
    }
}