@Test
    public void testInitMissingConfiguration() {
        val client = new DirectCasClient();
        TestsHelper.expectException(client::init, TechnicalException.class, "configuration cannot be null");
    }
Tests the {@link DirectCasClient}.

@author Jerome Leleu
@since 1.9.2
pac4j-cas/src/test/java/org/pac4j/cas/client/direct/DirectCasClientTests.java