@Test
    void verifyOperation() throws Throwable {
        val response = new MockHttpServletResponse();
        val request = new MockHttpServletRequest();
        request.setAttribute(DispatcherServlet.LOCALE_RESOLVER_ATTRIBUTE, new SessionLocaleResolver());

        oidcLocaleChangeInterceptor.preHandle(request, response, new Object());
        assertNull(request.getAttribute(Locale.class.getName()));

        val service = "https://localhost/cas/authz?ui_locales=de";
        request.addParameter(CasProtocolConstants.PARAMETER_SERVICE, service);
        oidcLocaleChangeInterceptor.preHandle(request, response, new Object());
        assertNotNull(request.getAttribute(Locale.class.getName()));
    }
This is {@link OidcLocaleChangeInterceptorTests}.

@author Misagh Moayyed
@since 6.4.0
support/cas-server-support-oidc/src/test/java/org/apereo/cas/oidc/web/OidcLocaleChangeInterceptorTests.java