fix #5711 restore original sort after group and ungroup

Author: dKab

src/features/grouping/js/grouping.js

@@ -674,6 +674,9 @@
         var existingGrouping = service.getGrouping( grid );
         column.grouping.groupPriority = existingGrouping.grouping.length;
 
+        // save sort in order to restore it when column is ungrouped
+        column.previousSort = angular.copy(column.sort);
+
         // add sort if not present
         if ( !column.sort ){
           column.sort = { direction: uiGridConstants.ASC };
@@ -716,9 +719,15 @@
         delete column.treeAggregation;
         delete column.customTreeAggregationFinalizer;
 
+        if (column.previousSort) {
+          column.sort = column.previousSort;
+          delete column.previousSort;
+        }
+
         service.tidyPriorities( grid );
 
         grid.api.grouping.raise.groupingChanged(column);
+        grid.api.core.raise.sortChanged(grid, grid.getColumnSorting());
 
         grid.queueGridRefresh();
       },

src/features/grouping/test/grouping.spec.js

@@ -101,6 +101,30 @@ describe('ui.grid.grouping uiGridGroupingService', function () {
   });
 
 
+  describe('groupColumn', function() {
+    it('saves previous sort state', function() {
+      grid.columns[1].sort = { priority: 42, direction: 'foo'};
+      uiGridGroupingService.groupColumn(grid, grid.columns[1]);
+      expect(grid.columns[1].previousSort.priority).toBe(42);
+      expect(grid.columns[1].previousSort.direction).toBe('foo');
+    });
+  });
+
+  describe('ungroupColumn', function() {
+    it('restores previuosly restored state if there is one', function() {
+      grid.columns[1].previousSort = { direction: 'bar'};
+      uiGridGroupingService.ungroupColumn(grid, grid.columns[1]);
+      expect(grid.columns[1].sort.direction).toBe('bar');
+    });
+
+    it('should remove previous sort prop from column object after column sort is restored', function() {
+      grid.columns[1].previousSort = {direction: 'bar'};
+      uiGridGroupingService.ungroupColumn(grid, grid.columns[1]);
+      expect(grid.columns[1].previousSort).toBeUndefined();
+    });
+  });
+
+
   describe( 'groupRows', function() {
     beforeEach(function() {
       spyOn(gridClassFactory, 'rowTemplateAssigner').and.callFake( function() {});