diff --git a/platform/core/src/models/ModelAggregator.js b/platform/core/src/models/ModelAggregator.js
index c2d331fd55..d02192830e 100644
--- a/platform/core/src/models/ModelAggregator.js
+++ b/platform/core/src/models/ModelAggregator.js
@@ -21,14 +21,9 @@ define(
             // Pick a domain object model to use, favoring the one
             // with the most recent timestamp
             function pick(a, b) {
-                if (!a) {
-                    return b;
-                }
-                if (!b) {
-                    return b;
-                }
-                return (a.modified || Number.NEGATIVE_INFINITY) >
-                    (b.modified || Number.NEGATIVE_INFINITY) ? a : b;
+                var aModified = (a || {}).modified || Number.NEGATIVE_INFINITY,
+                    bModified = (b || {}).modified || Number.NEGATIVE_INFINITY;
+                return (aModified > bModified) ? a : (b || a);
             }
 
             // Merge results from multiple providers into one
diff --git a/platform/core/test/capabilities/PersistenceCapabilitySpec.js b/platform/core/test/capabilities/PersistenceCapabilitySpec.js
index 0e4fefd6f7..d5be5bf659 100644
--- a/platform/core/test/capabilities/PersistenceCapabilitySpec.js
+++ b/platform/core/test/capabilities/PersistenceCapabilitySpec.js
@@ -16,16 +16,30 @@ define(
                 SPACE = "some space",
                 persistence;
 
+            function asPromise(value) {
+                return (value || {}).then ? value : {
+                    then: function (callback) {
+                        return asPromise(callback(value));
+                    }
+                };
+            }
+
             beforeEach(function () {
                 mockPersistenceService = jasmine.createSpyObj(
                     "persistenceService",
-                    [ "updateObject" ]
+                    [ "updateObject", "readObject" ]
                 );
                 mockDomainObject = {
                     getId: function () { return id; },
                     getModel: function () { return model; },
                     useCapability: jasmine.createSpy()
                 };
+                // Simulate mutation capability
+                mockDomainObject.useCapability.andCallFake(function (capability, mutator) {
+                    if (capability === 'mutation') {
+                        model = mutator(model) || model;
+                    }
+                });
                 persistence = new PersistenceCapability(
                     mockPersistenceService,
                     SPACE,
@@ -50,6 +64,31 @@ define(
                 expect(persistence.getSpace()).toEqual(SPACE);
             });
 
+            it("updates persisted timestamp on persistence", function () {
+                model.modified = 12321;
+                persistence.persist();
+                expect(model.persisted).toEqual(12321);
+            });
+
+            it("refreshes the domain object model from persistence", function () {
+                var refreshModel = { someOtherKey: "some other value" };
+                mockPersistenceService.readObject.andReturn(asPromise(refreshModel));
+                persistence.refresh();
+                expect(model).toEqual(refreshModel);
+            });
+
+            it("does not overwrite unpersisted changes on refresh", function () {
+                var refreshModel = { someOtherKey: "some other value" },
+                    mockCallback = jasmine.createSpy();
+                model.modified = 2;
+                model.persisted = 1;
+                mockPersistenceService.readObject.andReturn(asPromise(refreshModel));
+                persistence.refresh().then(mockCallback);
+                expect(model).not.toEqual(refreshModel);
+                // Should have also indicated that no changes were actually made
+                expect(mockCallback).toHaveBeenCalledWith(false);
+            });
+
         });
     }
 );
\ No newline at end of file
diff --git a/platform/core/test/models/ModelAggregatorSpec.js b/platform/core/test/models/ModelAggregatorSpec.js
index d01aeb022d..ff8e8ebf43 100644
--- a/platform/core/test/models/ModelAggregatorSpec.js
+++ b/platform/core/test/models/ModelAggregatorSpec.js
@@ -12,8 +12,8 @@ define(
             var mockQ,
                 mockProviders,
                 modelList = [
-                    { "a": { someKey: "some value" } },
-                    { "b": { someOtherKey: "some other value" } }
+                    { "a": { someKey: "some value" }, "b": undefined },
+                    { "b": { someOtherKey: "some other value" }, "a": undefined }
                 ],
                 aggregator;