Fix restoring getters/setters/values for previously unexisting props

lib/sinon/default-behaviors.js

@@ -1,6 +1,4 @@
 "use strict";
-var getPropertyDescriptor = require("./util/core/get-property-descriptor");
-
 var slice = [].slice;
 var useLeftMostCallback = -1;
 var useRightMostCallback = -2;
@@ -182,7 +180,8 @@ module.exports = {
         var rootStub = fake.stub || fake;
 
         Object.defineProperty(rootStub.rootObj, rootStub.propName, {
-            get: getterFunction
+            get: getterFunction,
+            configurable: true
         });
 
         return fake;
@@ -192,7 +191,8 @@ module.exports = {
         var rootStub = fake.stub || fake;
 
         Object.defineProperty(rootStub.rootObj, rootStub.propName, { // eslint-disable-line accessor-pairs
-            set: setterFunction
+            set: setterFunction,
+            configurable: true
         });
 
         return fake;
@@ -201,18 +201,12 @@ module.exports = {
     value: function value(fake, newVal) {
         var rootStub = fake.stub || fake;
 
-        var oldVal = getPropertyDescriptor(rootStub.rootObj, rootStub.propName).value;
-
         Object.defineProperty(rootStub.rootObj, rootStub.propName, {
-            value: newVal
+            value: newVal,
+            enumerable: true,
+            configurable: true
         });
 
-        fake.restore = function restore() {
-            Object.defineProperty(rootStub.rootObj, rootStub.propName, {
-                value: oldVal
-            });
-        };
-
         return fake;
     }
 };

lib/sinon/stub.js

@@ -45,7 +45,12 @@ function stub(object, property, descriptor) {
     s.rootObj = object;
     s.propName = property;
     s.restore = function restore() {
-        Object.defineProperty(object, property, actualDescriptor);
+        if (actualDescriptor !== undefined) {
+            Object.defineProperty(object, property, actualDescriptor);
+            return;
+        }
+
+        delete object[property];
     };
 
     return isStubbingNonFuncProperty ? s : wrapMethod(object, property, s);

test/stub-test.js

@@ -5,11 +5,12 @@ var createStub = require("../lib/sinon/stub");
 var createStubInstance = require("../lib/sinon/stub").createStubInstance;
 var createSpy = require("../lib/sinon/spy");
 var sinonMatch = require("../lib/sinon/match");
+var getPropertyDescriptor = require("../lib/sinon/util/core/get-property-descriptor");
+var deprecated = require("../lib/sinon/util/core/deprecated");
 var assert = referee.assert;
 var refute = referee.refute;
 var fail = referee.fail;
 var Promise = require("native-promise-only"); // eslint-disable-line no-unused-vars
-var deprecated = require("../lib/sinon/util/core/deprecated");
 
 describe("stub", function () {
     it("is spy", function () {
@@ -2519,6 +2520,20 @@ describe("stub", function () {
 
             assert.equals(myObj.prop, "bar");
         });
+
+        it("can restore stubbed getters for previously undefined properties", function () {
+            var myObj = {};
+
+            var stub = createStub(myObj, "nonExisting");
+
+            stub.get(function getterFn() {
+                return "baz";
+            });
+
+            stub.restore();
+
+            assert.equals(getPropertyDescriptor(myObj, "nonExisting"), undefined);
+        });
     });
 
     describe(".set", function () {
@@ -2619,6 +2634,20 @@ describe("stub", function () {
             myObj.prop = "foo";
             assert.equals(myObj.otherProp, "bar");
         });
+
+        it("can restore stubbed setters for previously undefined properties", function () {
+            var myObj = {};
+
+            var stub = createStub(myObj, "nonExisting");
+
+            stub.set(function setterFn() {
+                myObj.otherProp = "baz";
+            });
+
+            stub.restore();
+
+            assert.equals(getPropertyDescriptor(myObj, "nonExisting"), undefined);
+        });
     });
 
     describe(".value", function () {
@@ -2641,5 +2670,14 @@ describe("stub", function () {
 
             assert.equals(myObj.prop, "rawString");
         });
+
+        it("allows restoring previously undefined properties", function () {
+            var obj = {};
+            var stub = createStub(obj, "nonExisting").value(2);
+
+            stub.restore();
+
+            assert.equals(getPropertyDescriptor(obj, "nonExisting"), undefined);
+        });
     });
 });