diff --git a/platform/framework/test/register/ExtensionRegistrarSpec.js b/platform/framework/test/register/ExtensionRegistrarSpec.js
index 70811c09f4..c89417da4b 100644
--- a/platform/framework/test/register/ExtensionRegistrarSpec.js
+++ b/platform/framework/test/register/ExtensionRegistrarSpec.js
@@ -11,14 +11,24 @@ define(
         describe("The extension registrar", function () {
             var mockApp,
                 mockLog,
+                mockSorter,
                 customRegistrars,
                 registrar;
 
             beforeEach(function () {
                 mockApp = jasmine.createSpyObj("app", ["factory"]);
                 mockLog = jasmine.createSpyObj("$log", ["error", "warn", "debug", "info"]);
+                mockSorter = jasmine.createSpyObj("sorter", ["sort"]);
                 customRegistrars = {};
-                registrar = new ExtensionRegistrar(mockApp, customRegistrars, mockLog);
+
+                mockSorter.sort.andCallFake(function (v) { return v; });
+
+                registrar = new ExtensionRegistrar(
+                    mockApp,
+                    customRegistrars,
+                    mockSorter,
+                    mockLog
+                );
             });
 
             it("registers extensions using the factory", function () {
@@ -64,6 +74,23 @@ define(
                 expect(customRegistrars.things).toHaveBeenCalled();
             });
 
+            it("sorts extensions before registering", function () {
+                // Some extension definitions to sort
+                var a = { a: 'a' }, b = { b: 'b' }, c = { c: 'c' };
+
+                // Fake sorting; just reverse the array
+                mockSorter.sort.andCallFake(function (v) { return v.reverse(); });
+
+                // Register the extensions
+                registrar.registerExtensions({ things: [ a, b, c ] });
+
+                // Verify registration interactions occurred in reverse-order
+                [ c, b, a ].forEach(function (extension, index) {
+                    expect(mockApp.factory.calls[index].args[1][0]())
+                        .toEqual(extension);
+                });
+            });
+
         });
     }
 );
\ No newline at end of file
diff --git a/platform/framework/test/register/ExtensionSorterSpec.js b/platform/framework/test/register/ExtensionSorterSpec.js
new file mode 100644
index 0000000000..a51ece21eb
--- /dev/null
+++ b/platform/framework/test/register/ExtensionSorterSpec.js
@@ -0,0 +1,50 @@
+/*global define,Promise,describe,it,expect,beforeEach,jasmine,waitsFor*/
+
+define(
+    ["../../src/register/ExtensionSorter"],
+    function (ExtensionSorter) {
+        "use strict";
+
+        describe("The extension sorter", function () {
+            var mockLog,
+                sorter;
+
+            beforeEach(function () {
+                mockLog = jasmine.createSpyObj(
+                    "$log",
+                    ["error", "warn", "debug", "info"]
+                );
+
+                sorter = new ExtensionSorter(mockLog);
+            });
+
+            it("sorts extensions in priority order", function () {
+                var a = { priority: 10 },
+                    b = {},
+                    c = { priority: 'mandatory' }; // Should be +Inf
+                expect(sorter.sort([a, b, c])).toEqual([c, a, b]);
+            });
+
+            it("warns about unrecognized priorities", function () {
+                var a = { priority: 10 },
+                    b = {},
+                    c = { priority: 'mandatory' }, // Should be +Inf
+                    d = { priority: 'GARBAGE-TEXT' },
+                    e = { priority: { mal: "formed"} },
+                    f = { priority: 3 };
+
+                // Sorting should use default order (note we assume
+                // a stable sort here as well)
+                expect(sorter.sort(
+                    [a, b, c, d, e, f]
+                )).toEqual(
+                    [c, a, f, b, d, e]
+                );
+
+                // Should have been warned exactly twice (for d & e)
+                expect(mockLog.warn.calls.length).toEqual(2);
+            });
+
+        });
+    }
+);
diff --git a/platform/framework/test/suite.json b/platform/framework/test/suite.json
index a46a4ecfe7..93504f01af 100644
--- a/platform/framework/test/suite.json
+++ b/platform/framework/test/suite.json
@@ -6,6 +6,7 @@
     "load/Extension",
     "register/CustomRegistrars",
     "register/ExtensionRegistrar",
+    "register/ExtensionSorter",
     "register/PartialConstructor",
     "register/ServiceCompositor",
     "resolve/BundleResolver",