fix(datepicker): correctly change months

src/datepicker/datepicker.js

@@ -228,6 +228,7 @@ angular.module('ui.bootstrap.datepicker', ['ui.bootstrap.position'])
       };
       scope.move = function(direction) {
         var step = datepickerCtrl.modes[mode].step;
+        selected.setDate(1); // Avoid having a day that doesn't exist on the objective month.
         selected.setMonth( selected.getMonth() + direction * (step.months || 0) );
         selected.setFullYear( selected.getFullYear() + direction * (step.years || 0) );
         refill();

src/datepicker/test/datepicker.spec.js

@@ -219,6 +219,44 @@ describe('datepicker directive', function () {
       expectSelectedElement( 0, 4 );
     });
 
+    it('issue 1697 - moves to the next month & render correctly when the selected day doesnt exist on the next month', function() {
+      $rootScope.date = new Date('January 31, 2010 15:30:00');
+      $rootScope.$digest();
+
+      clickNextButton();
+
+      expect(getTitle()).toBe('February 2010');
+      expect(getLabels()).toEqual(['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat']);
+      expect(getOptions()).toEqual([
+        ['31', '01', '02', '03', '04', '05', '06'],
+        ['07', '08', '09', '10', '11', '12', '13'],
+        ['14', '15', '16', '17', '18', '19', '20'],
+        ['21', '22', '23', '24', '25', '26', '27'],
+        ['28', '01', '02', '03', '04', '05', '06']
+      ]);
+
+      expectSelectedElement( 0, 0 );
+    });
+
+    it('issue 1697 - moves to the previous month & render correctly when the selected day doesnt exist on the previous month', function() {
+      $rootScope.date = new Date('March 31, 2010 15:30:00');
+      $rootScope.$digest();
+
+      clickPreviousButton();
+
+      expect(getTitle()).toBe('February 2010');
+      expect(getLabels()).toEqual(['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat']);
+      expect(getOptions()).toEqual([
+        ['31', '01', '02', '03', '04', '05', '06'],
+        ['07', '08', '09', '10', '11', '12', '13'],
+        ['14', '15', '16', '17', '18', '19', '20'],
+        ['21', '22', '23', '24', '25', '26', '27'],
+        ['28', '01', '02', '03', '04', '05', '06']
+      ]);
+
+      expectSelectedElement( null, null );
+    });
+
     it('updates the model only when a day is clicked in the `next` month', function() {
       clickNextButton();
       expect($rootScope.date).toEqual(new Date('September 30, 2010 15:30:00'));