Description: ------------ The library currently uses protected class members to test if their is old data available. This can fail under some conditions, i.e., the test if (isset($cache->_file) && file_exists($cache->_file)) { returns true, but if ($data = $cache->get($cacheID, 'default', true)) fails later. A more reliable, albeit slightly less efficient, method is to use the real cache->get test before attempting the conditional HTTP GET.

Henning, want to take a look at the CVS version? I've done some pretty major refactoring to get unit tests, etc up and running - there's now a concept of 'transport' classes which you can swap in and out. If you wanted to write unit tests against Services_ExchangeRates_Transport_HTTP_Cached that owuld be really handy.