안 좋은 코드의 교과서인 제 코드에 대한 해결 방법이 있을까요?

@Test
	public void testClientSessionKey_theParameterClientRSAIsNull() {
		ClientRSAIF clientRSA = null;
		String symmetricKeyAlgorithm = null;
		int symmetricKeySize = -1;
		int symmetricIVSize = -1;
		boolean isBase64 = false;
 
		try {
			new ClientSessionKey(clientRSA, symmetricKeyAlgorithm, symmetricKeySize, symmetricIVSize, isBase64);
 
			fail("no IllegalArgumentException");
		} catch (IllegalArgumentException e) {
			String errorMessage = e.getMessage();
			String expcetedMessage = "the parameter clientRSA is null";
 
			assertEquals(expcetedMessage, errorMessage);
 
		} catch (Exception e) {
			log.log(Level.WARNING, "unknown error", e);
 
			fail("fail to create a instance of ClientSessionKey class becase of unknown error");
		}
	}