How to cover block catch by JUnit with NoSuchAlgor

问题:

I want to cover getKeyStore() methode, But I don't know how to cover catch block for NoSuchAlgorithmException, KeyStoreException, UnrecoverableKeyException and CertificateException. My methode is :

---

public static KeyManagerFactory getKeyStore(String keyStoreFilePath)
        throws IOException {
    KeyManagerFactory keyManagerFactory = null;
    InputStream kmf= null;
    try {
        keyManagerFactory = KeyManagerFactory.getInstance("SunX509");
        KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
        keystoreStream = new FileInputStream(keyStoreFilePath);
        keyStore.load(keystoreStream, "changeit".toCharArray());
        kmf.init(keyStore, "changeit".toCharArray());
    } catch (NoSuchAlgorithmException e) {
        LOGGER.error(ERROR_MESSAGE_NO_SUCH_ALGORITHM + e);
    } catch (KeyStoreException e) {
        LOGGER.error(ERROR_MESSAGE_KEY_STORE + e);
    } catch (UnrecoverableKeyException e) {
        LOGGER.error(ERROR_MESSAGE_UNRECOVERABLEKEY + e);
    } catch (CertificateException e) {
        LOGGER.error(ERROR_MESSAGE_CERTIFICATE + e);
    } finally {
        try {
            if (keystoreStream != null){
                keystoreStream.close();
            }
        } catch (IOException e) {
            LOGGER.error(ERROR_MESSAGE_IO + e);
        }
    }
    return kmf;
}

---

How do I do it?

回答1:

You can mock any sentence of the try block to throw the exception you want to catch.

Example mocking the KeyManagerFactory.getInstance call to throw NoSuchAlgorithmException. In that case, you will cover the first catch block, you have to do the same with other exceptions caught (KeyStoreException, UnrecoverableKeyException and CertificateException)

You can do as follows (as method getInstance is static, you have to use PowerMockito instead Mockito, see this question for more info)

@PrepareForTest(KeyManagerFactory.class)
@RunWith(PowerMockRunner.class)
public class FooTest {

   @Test
   public void testGetKeyStore() throws Exception {
      PowerMockito.mockStatic(KeyManagerFactory.class);
      when(KeyManagerFactory.getInstance(anyString())).thenThrow(new NoSuchAlgorithmException());
   }
}

Hope it helps