diff -r 000000000000 -r 6474c204b198 netwerk/test/unit/test_cache2-01b-basic-datasize.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/netwerk/test/unit/test_cache2-01b-basic-datasize.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,32 @@
+function run_test()
+{
+  do_get_profile();
+
+  // Open for write, write
+  asyncOpenCacheEntry("http://a/", "disk", Ci.nsICacheStorage.OPEN_NORMALLY, null,
+    new OpenCallback(NEW|WAITFORWRITE, "a1m", "a1d", function(entry) {
+      // Open for read and check
+      do_check_eq(entry.dataSize, 3);
+      asyncOpenCacheEntry("http://a/", "disk", Ci.nsICacheStorage.OPEN_NORMALLY, null,
+        new OpenCallback(NORMAL, "a1m", "a1d", function(entry) {
+          // Open for rewrite (truncate), write different meta and data
+          do_check_eq(entry.dataSize, 3);
+          asyncOpenCacheEntry("http://a/", "disk", Ci.nsICacheStorage.OPEN_TRUNCATE, null,
+            new OpenCallback(NEW|WAITFORWRITE, "a2m", "a2d", function(entry) {
+              // Open for read and check
+              do_check_eq(entry.dataSize, 3);
+              asyncOpenCacheEntry("http://a/", "disk", Ci.nsICacheStorage.OPEN_NORMALLY, null,
+                new OpenCallback(NORMAL, "a2m", "a2d", function(entry) {
+                  do_check_eq(entry.dataSize, 3);
+                  finish_cache2_test();
+                })
+              );
+            })
+          );
+        })
+      );
+    })
+  );
+
+  do_test_pending();
+}