[not part of build] Tests disk cache using XPConnnect.

netwerk/test/TestDiskCache.js

@@ -0,0 +1,38 @@
+function getCacheService()
+{
+    var nsCacheService = Components.classes["@mozilla.org/network/cache-service;1"];
+    var service = nsCacheService.getService(Components.interfaces.nsICacheService);
+    return service;
+}
+
+function createCacheSession(clientID, storagePolicy, streamable)
+{
+    var service = getCacheService();
+    var nsICache = Components.interfaces.nsICache;
+    var session = service.createSession(clientID, storagePolicy, streamable);
+    return session;
+}
+
+function openCacheEntry()
+{
+    var nsICache = Components.interfaces.nsICache;
+    var session = createCacheSession("javascript", nsICache.STORE_ON_DISK, true);
+    var entry = session.openCacheEntry("theme:button", nsICache.ACCESS_READ_WRITE);
+    return entry;
+}
+
+function dumpLeaks()
+{
+    var leakDetector = Components.classes["@mozilla.org/xpcom/leakdetector;1"].getService(Components.interfaces.nsILeakDetector);
+    leakDetector.dumpLeaks();
+}
+
+var entry = openCacheEntry();
+var transport = entry.transport;
+var output = transport.openOutputStream(0, -1, 0);
+if (output.write("foo", 3) == 3)
+    print("disk cache works!");
+else
+    print("disk cache sucks!");
+entry.markValid();
+entry.close();