verify(this.mechContext, never()).initSecContext(any(), anyInt(), anyInt());
    }

    @Test
    @DisplayName("initSecContext with null buffer and non-zero len throws NPE")
    void testInitSecContextNullBufferNonZeroLen() throws Exception {
        SpnegoContext ctx = newContext();
        // A null buffer with non-zero len leads to NPE while slicing input