### Question:
JSSwitchUserProcessingFilter extends SwitchUserFilter { public void afterPropertiesSet() { super.afterPropertiesSet(); Assert.hasLength(jsTargetUrl, "jsTargetUrl must be specified"); Assert.hasLength(exitTargetUrl, "exitTargetUrl must be specified"); }  void setAuditContext(AuditContext auditContext); void afterPropertiesSet(); void doFilter(ServletRequest req, ServletResponse res, FilterChain chain); void setTargetUrl(String targetUrl); void setExitTargetUrl(String exitTargetUrl); ThemeResolver getThemeResolver(); void setThemeResolver(ThemeResolver themeResolver);  }### Answer:
@Test public void afterPropertiesSet_userDetailsServiceIsNull_illegalArgumentException() { objectUnderTest.setUserDetailsService(null); assertThrows(IllegalArgumentException.class, new Executable() { @Override public void execute() { objectUnderTest.afterPropertiesSet(); } }); }