when(locator.handleDFSReferral(null, "")).thenReturn("smb://server/share/");
        assertEquals("smb://server/share/", locator.handleDFSReferral(null, ""));
        verify(locator).handleDFSReferral(null, "");
        verifyNoMoreInteractions(locator);
    }

    // Invalid input: null reqPath leads to NPE from implementation
    @Test
    @DisplayName("handleDFSReferral throws NPE on null reqPath")

    /**
     * Internal: for testing only
     *
     * @param dr the DFS referral data to process
     * @param reqPath the requested path to resolve
     * @return resolved unc path
     */
    String handleDFSReferral(DfsReferralData dr, String reqPath);