Covers uses of 'Last-Modified' header to compute heuristic freshness.

On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".


running 3 tests

--------Testing loads from disk cache--------
response headers: {"Last-Modified":"Thu, 01 Jan 2000 00:00:00 GMT"}
response source: Disk cache

response headers: {"Last-Modified":"Thu, 01 Jan 1970 00:00:00 GMT"}
response source: Network

response headers: {"Last-Modified":"invalid"}
response source: Network

--------Testing loads through memory cache (XHR behavior)--------
response headers: {"Last-Modified":"Thu, 01 Jan 2000 00:00:00 GMT"}
response source: Memory cache

response headers: {"Last-Modified":"Thu, 01 Jan 1970 00:00:00 GMT"}
response source: Network

response headers: {"Last-Modified":"invalid"}
response source: Network

--------Testing loads through memory cache (subresource behavior)--------
response headers: {"Last-Modified":"Thu, 01 Jan 2000 00:00:00 GMT"}
response source: Memory cache

response headers: {"Last-Modified":"Thu, 01 Jan 1970 00:00:00 GMT"}
response source: Network

response headers: {"Last-Modified":"invalid"}
response source: Network

PASS successfullyParsed is true

TEST COMPLETE