fix: muk can mock accessor descriptor now

lib/method.js

@@ -1,3 +1,5 @@
+'use strict';
+
 // keep track of mocks
 var mocks = [];
 
@@ -13,9 +15,10 @@ var method = module.exports = function mockMethod(obj, key, method) {
   mocks.push({
     obj: obj,
     key: key,
-    original: obj[key],
+    descriptor: Object.getOwnPropertyDescriptor(obj, key),
     exist: key in obj
   });
+  delete obj[key];
   obj[key] = method === undefined ? function() {} : method;
 };
 
@@ -29,7 +32,7 @@ method.restore = function restoreMocks() {
     if (!m.exist) {
       delete m.obj[m.key];
     } else {
-      m.obj[m.key] = m.original;
+      Object.defineProperty(m.obj, m.key, m.descriptor);
     }
   }
   mocks = [];

test/method-test.js

@@ -1,3 +1,5 @@
+'use strict';
+
 var muk    = require('..');
 var assert = require('assert');
 var fs     = require('fs');
@@ -87,6 +89,29 @@ describe('Mock property', function () {
   });
 });
 
+describe('Mock getter', function() {
+  var obj = {
+    get a() {
+      return 1;
+    }
+  };
+
+  it('Contains original getter', function() {
+    assert.equal(obj.a, 1, 'property a of obj is 1');
+  });
+
+  it('Methods are new getter after mocked', function() {
+    muk(obj, 'a', 2);
+    assert.equal(obj.a, 2, 'property a of obj is equal to mock');
+  });
+
+  it('Should have original getter after muk.restore()', function() {
+    muk(obj, 'a', 2);
+    muk.restore();
+    assert.equal(obj.a, 1, 'property a of obj is equal to mock');
+  });
+});
+
 function hasOwnProperty(obj, prop) {
   return Object.prototype.hasOwnProperty.call(obj, prop);
 }