private Certificate certificateWithKeyUsage(int keyUsage) {
        // note the rare usage of non-zero keyUsage
        return new TestKeyStore.Builder()
                .aliasPrefix("rsa-dsa-ec")
                .keyUsage(keyUsage)
                .build()
                .getPrivateKey("RSA", "RSA").getCertificate();
    }
Try various .init(...) calls with null parameters to make sure it is
handled.
common/src/test/java/org/conscrypt/javax/crypto/CipherTest.java