diff -r 000000000000 -r 6474c204b198 toolkit/components/osfile/tests/mochi/worker_test_osfile_comms.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/components/osfile/tests/mochi/worker_test_osfile_comms.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,141 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+importScripts('worker_test_osfile_shared.js');
+
+// The set of samples for communications test. Declare as a global
+// variable to prevent this from being garbage-collected too early.
+let samples;
+
+self.onmessage = function(msg) {
+  info("Initializing");
+  self.onmessage = function on_unexpected_message(msg) {
+    throw new Error("Unexpected message " + JSON.stringify(msg.data));
+  };
+  importScripts("resource://gre/modules/osfile.jsm");
+  info("Initialization complete");
+
+  samples = [
+    { typename: "OS.Shared.Type.char.in_ptr",
+      valuedescr: "String",
+      value: "This is a test",
+      type: OS.Shared.Type.char.in_ptr,
+      check: function check_string(candidate, prefix) {
+        is(candidate, "This is a test", prefix);
+      }},
+    { typename: "OS.Shared.Type.char.in_ptr",
+      valuedescr: "Typed array",
+      value: (function() {
+                let view = new Uint8Array(15);
+                for (let i = 0; i < 15; ++i) {
+                  view[i] = i;
+                }
+                return view;
+              })(),
+      type: OS.Shared.Type.char.in_ptr,
+      check: function check_ArrayBuffer(candidate, prefix) {
+        let cast = ctypes.cast(candidate, ctypes.uint8_t.ptr);
+        for (let i = 0; i < 15; ++i) {
+          is(cast.contents, i % 256, prefix + "Checking that the contents of the ArrayBuffer were preserved");
+          cast = cast.increment();
+        }
+      }},
+    { typename: "OS.Shared.Type.char.in_ptr",
+      valuedescr: "Pointer",
+      value: new OS.Shared.Type.char.in_ptr.implementation(1),
+      type: OS.Shared.Type.char.in_ptr,
+      check: function check_ptr(candidate, prefix) {
+        let address = ctypes.cast(candidate, ctypes.uintptr_t).value.toString();
+        is(address, "1", prefix + "Checking that the pointer address was preserved");
+      }},
+    { typename: "OS.Shared.Type.char.in_ptr",
+      valuedescr: "C array",
+      value: (function() {
+                let buf = new (ctypes.ArrayType(ctypes.uint8_t, 15))();
+                for (let i = 0; i < 15; ++i) {
+                  buf[i] = i % 256;
+                }
+                return buf;
+              })(),
+      type: OS.Shared.Type.char.in_ptr,
+      check: function check_array(candidate, prefix) {
+        let cast = ctypes.cast(candidate, ctypes.uint8_t.ptr);
+        for (let i = 0; i < 15; ++i) {
+          is(cast.contents, i % 256, prefix + "Checking that the contents of the C array were preserved, index " + i);
+          cast = cast.increment();
+        }
+      }
+    },
+    { typename: "OS.File.Error",
+      valuedescr: "OS Error",
+      type: OS.File.Error,
+      value: new OS.File.Error("foo", 1),
+      check: function check_error(candidate, prefix) {
+        ok(candidate instanceof OS.File.Error,
+          prefix + "Error is an OS.File.Error");
+        ok(candidate.unixErrno == 1 || candidate.winLastError == 1,
+           prefix + "Error code is correct");
+        try {
+          let string = candidate.toString();
+          info(prefix + ".toString() works " + string);
+        } catch (x) {
+          ok(false, prefix + ".toString() fails " + x);
+        }
+      }
+    }
+  ];
+  samples.forEach(function test(sample) {
+    let type = sample.type;
+    let value = sample.value;
+    let check = sample.check;
+    info("Testing handling of type " + sample.typename + " communicating " + sample.valuedescr);
+
+    // 1. Test serialization
+    let serialized;
+    let exn;
+    try {
+      serialized = type.toMsg(value);
+    } catch (ex) {
+      exn = ex;
+    }
+    is(exn, null, "Can I serialize the following value? " + value +
+      " aka " + JSON.stringify(value));
+    if (exn) {
+      return;
+    }
+
+    // 2. Test deserialization
+    let deserialized;
+    try {
+      deserialized = type.fromMsg(serialized);
+    } catch (ex) {
+      exn = ex;
+    }
+    is(exn, null, "Can I deserialize the following message? " + serialized
+     + " aka " + JSON.stringify(serialized));
+    if (exn) {
+      return;
+    }
+
+    // 3. Local test deserialized value
+    info("Running test on deserialized value " + serialized);
+    check(deserialized, "Local test: ");
+
+    // 4. Test sending serialized
+    info("Attempting to send message");
+    try {
+      self.postMessage({kind:"value",
+        typename: sample.typename,
+        value: serialized,
+        check: check.toSource()});
+    } catch (ex) {
+      exn = ex;
+    }
+    is(exn, null, "Can I send the following message? " + serialized
+     + " aka " + JSON.stringify(serialized));
+  });
+
+  finish();
+ };