c# - MemoryCache: Why is this integration test failing? UpdateCallBack looks like it's broken -

in sane world, have expected updatecallback property increment collection of arguments. doesn't: in final line of test, updatearguments collection expected 3 (twice each set call , once remove call), empty.

the test rough , ready, should enough illustrate odd happening.

or missing obvious.

edit: getting stranger. based on question memorycache updatecallback not working, says thread.sleep blocks memorycache.default object, changed original thread.sleep(5000) call task.factory.startnew(() => thread.sleep(10000)).wait();. then, if comment out call memorycache.default.remove(), updatearguments collection indeed incremented, once, , when "personkey" cached item expires. 2 set() , 1 remove() calls ignored completely. i'm having "what heck" moment.

[test] public void thememorycachemaintainsamemberandinvokestheupdatecallback() {     var person = new person { givenname = "rob", lastname = "lyndon"};     var givenname = person.givenname;     var lastname = person.lastname;      var updatearguments = new list<cacheentryupdatearguments>();      memorycache.default.set("personkey", person, createnewpolicy(updatearguments));     var cacheditem = memorycache.default.get("personkey") person;     assert.isnotnull(cacheditem);     assert.that(cacheditem.givenname, is.equalto(givenname));     assert.that(cacheditem.lastname, is.equalto(lastname));      person.lastname = "lyndon - updated";     memorycache.default.set("personkey", member, createnewpolicy(updatearguments));     cacheditem = memorycache.default.get("personkey") person;     assert.isnotnull(cacheditem);     assert.that(cacheditem.givenname, is.equalto(givenname));     assert.that(cacheditem.lastname, is.equalto(lastname + " - updated"));      task.factory.startnew(() => thread.sleep(10000)).wait();     thread.sleep(5000);     assert.that(updatearguments.count, is.equalto(3)); }  private static cacheitempolicy createnewpolicy(icollection<cacheentryupdatearguments> updatearguments) {     return new cacheitempolicy         {             absoluteexpiration = datetimeoffset.now.addseconds(1),             updatecallback = args => updatearguments.add(args)         }; }