@Test
public void TestGetEtagForExistingPolicy_BadPolicyFileDir_IllegalArgs() throws Exception {

    
    PolicyUpdaterConfiguration configMock = Mockito.mock(PolicyUpdaterConfiguration.class);
    Mockito.when(configMock.getPolicyFileDir()).thenReturn(null);
    
    // Test error handling for illegal arguments
    boolean exceptionCaught = false;
    
    try {
        PolicyUpdater.getEtagForExistingPolicy(null, configMock, "testDomain");
    } catch (IllegalArgumentException ex) {
        exceptionCaught = true;
    }
    Assert.assertTrue(exceptionCaught);
}