Stub out the system clock in the download manager, add tests

Introduce SystemFacade, an interface that allows us to stub out the
system clock for testing the download manager.  This allows us to test
retrying a failed download without having the test wait 60 seconds.
This interface can include other dependencies in the future as well.

I've also used this to add tests for 503 (retry-after) and 301
(redirect), and I've added a test for download to the cache partition.

Other changes:
* made MockWebServer capable of checking + rethrowing exceptions from child threads
* refactoring + cleanup of DownloadManagerFunctionalTest

1 files changed, 6 insertions, 0 deletions

diff --git a/src/com/android/providers/downloads/SystemFacade.java b/src/com/android/providers/downloads/SystemFacade.java
new file mode 100644
index 00000000..4498877d
--- /dev/null
+++ b/src/com/android/providers/downloads/SystemFacade.java
@@ -0,0 +1,6 @@
+
+package com.android.providers.downloads;
+
+interface SystemFacade {
+    public long currentTimeMillis();
+}