Fixed product validation bug

Skipping product validation when retrieving data from the server after saving.

ECOM-2075

ecommerce/static/js/models/course_model.js

@@ -81,7 +81,9 @@ define([
                     }
                 },
                 products: function (value) {
-                    if (!value.isValid()) {
+                    // NOTE (CCB): When syncing from the server, the value is an array. We can safely ignore
+                    // validation in this case since the values from the server should be valid.
+                    if (!_.isArray(value) && !value.isValid()) {
                         return gettext('Product validation failed.');
                     }
                 }

ecommerce/static/js/test/specs/models/course_model_spec.js

@@ -249,15 +249,23 @@ define([
             });
 
             describe('products validation', function () {
-                it('should return an error message if any product is invalid', function () {
-                    var msg = 'Product validation failed.',
-                        products = model.get('products');
+                describe('with single value', function () {
+                    it('should return an error message if any product is invalid', function () {
+                        var msg = 'Product validation failed.',
+                            products = model.get('products');
 
-                    // Add an invalid product
-                    products.push(new ProfessionalSeat({price: null}));
+                        // Add an invalid product
+                        products.push(new ProfessionalSeat({price: null}));
 
-                    expect(model.validate().products).toEqual(msg);
-                    expect(model.isValid(true)).toBeFalsy();
+                        expect(model.validate().products).toEqual(msg);
+                        expect(model.isValid(true)).toBeFalsy();
+                    });
+                });
+
+                describe('with non-products', function () {
+                    it('should have an undefined return value', function () {
+                        expect(model.validation.products([])).toBeUndefined();
+                    });
                 });
             });
         });