diff --git a/src/apps.js b/src/apps.js
index 362eee45b..820ea0087 100644
--- a/src/apps.js
+++ b/src/apps.js
@@ -2468,7 +2468,7 @@ async function clone(app, data, user, auditSource) {
     };
     const taskId = await addTask(newAppId, exports.ISTATE_PENDING_CLONE, task, auditSource);
 
-    const newApp = Object.assign({}, _.omit(obj, 'icon'), { appStoreId, manifest, subdomain, domain, portBindings });
+    const newApp = Object.assign({}, _.omit(obj, ['icon']), { appStoreId, manifest, subdomain, domain, portBindings });
     newApp.fqdn = dns.fqdn(newApp.subdomain, newApp.domain);
     newApp.secondaryDomains.forEach(function (ad) { ad.fqdn = dns.fqdn(ad.subdomain, ad.domain); });
     newApp.redirectDomains.forEach(function (ad) { ad.fqdn = dns.fqdn(ad.subdomain, ad.domain); });
@@ -2545,7 +2545,7 @@ async function unarchive(archive, data, auditSource) {
 
     const taskId = await addTask(appId, obj.installationState, task, auditSource);
 
-    const newApp = Object.assign({}, _.omit(obj, 'icon'), { appStoreId, manifest, subdomain, domain, portBindings });
+    const newApp = Object.assign({}, _.omit(obj, ['icon']), { appStoreId, manifest, subdomain, domain, portBindings });
     newApp.fqdn = dns.fqdn(newApp.subdomain, newApp.domain);
     newApp.secondaryDomains.forEach(function (ad) { ad.fqdn = dns.fqdn(ad.subdomain, ad.domain); });
     newApp.redirectDomains.forEach(function (ad) { ad.fqdn = dns.fqdn(ad.subdomain, ad.domain); });
diff --git a/src/test/underscore-test.js b/src/test/underscore-test.js
new file mode 100644
index 000000000..373cabb87
--- /dev/null
+++ b/src/test/underscore-test.js
@@ -0,0 +1,51 @@
+'use strict';
+
+/* global it, describe, before, after */
+
+const expect = require('expect.js'),
+    _ = require('../underscore.js');
+
+describe('Underscore', function () {
+    it('pick', function () {
+        expect(_.pick({ x: 1, y: 2 }, ['x'])).to.eql({x: 1});
+        expect(_.pick({ x: 1, y: 2 }, ['x', 'y', 'z'])).to.eql({x: 1, y:2});
+        expect(_.pick({ x: 1, y: 2 }, ['z'])).to.eql({});
+        expect(_.pick({ x: 1, y: 2 }, [])).to.eql({});
+    });
+
+    it('omit', function () {
+        expect(_.omit({ x: 1, y: 2 }, ['x'])).to.eql({ y: 2 });
+        expect(_.omit({ x: 1, y: 2 }, ['x', 'y', 'z'])).to.eql({});
+        expect(_.omit({ x: 1, y: 2 }, ['z'])).to.eql({ x: 1, y: 2 });
+        expect(_.omit({ x: 1, y: 2 }, [])).to.eql({ x: 1, y: 2 });
+    });
+
+    it('intersection', function () {
+        expect(_.intersection([], [2,3])).to.eql([]);
+        expect(_.intersection([1,2], [2,3])).to.eql([2]);
+        expect(_.intersection([1,2], [3])).to.eql([]);
+        expect(_.intersection([1,2], [1,2])).to.eql([1,2]);
+    });
+
+    it('isEqual', function () {
+        expect(_.isEqual(null, null)).to.be(true);
+
+        expect(_.isEqual(1, 1)).to.be(true);
+        expect(_.isEqual(1, 2)).to.be(false);
+
+        expect(_.isEqual([], [])).to.be(true);
+        expect(_.isEqual([2,3,4], [3,4,2])).to.be(false);
+
+        expect(_.isEqual({x:1}, {y:2})).to.be(false);
+        expect(_.isEqual({x:1}, {x:1})).to.be(true);
+        expect(_.isEqual({x:1,z:2}, {z:1,x:1})).to.be(false);
+        expect(_.isEqual({x:1,y:3,z:2}, {y:3,z:2,x:1})).to.be(true);
+    });
+
+    it('difference', function () {
+        expect(_.difference([1,2], [2,3])).to.eql([1]);
+        expect(_.difference([1,2], [3])).to.eql([1,2]);
+        expect(_.difference([1,2], [1,2])).to.eql([]);
+        expect(_.difference([], [1,2])).to.eql([]);
+    });
+});
diff --git a/src/underscore.js b/src/underscore.js
index e857ae378..465071fd2 100644
--- a/src/underscore.js
+++ b/src/underscore.js
@@ -8,6 +8,7 @@ exports = module.exports = {
     difference
 };
 
+// IMPORTANT: this file is required from the migration logic. avoid requires
 const assert = require('assert');
 
 function pick(obj, keys) {