Added spy.returnsInOrder method

lib/spy.js

@@ -164,6 +164,27 @@ module.exports = function (chai, _) {
     });
   };
 
+  /**
+   * # chai.spy.returnsInOrder (function)
+   *
+   * Creates a spy which returns different value each time it is called (in defined order).
+   *
+   *      var method = chai.spy.returnsInOrder(['first', 'second']);
+   *      method().should.equal('first');
+   *      method().should.equal('second');
+   *
+   * @param {Object[]} [values] array of values be returned by the spy
+   * @returns new spy function which returns values in given order
+   * @api public
+   */
+
+  chai.spy.returnsInOrder = function (values) {
+    var currentIndex = 0;
+    return chai.spy(function () {
+      return values[currentIndex++];
+    });
+  };
+
   /**
    * # spy
    *

test/spies.js

@@ -224,6 +224,15 @@ describe('Chai Spies', function () {
     spy().should.equal(value);
   });
 
+  it('should create spy which returns multiple different values in order', function(){
+    var values = ['value1', 'value2']
+    var spy = chai.spy.returnsInOrder(values);
+
+    spy.should.be.a.spy;
+    spy().should.equal(values[0]);
+    spy().should.equal(values[1]);
+  });
+
   it('should spy multiple object methods passed as array', function () {
     var array = chai.spy.on([], 'push', 'pop');