[FIX] web: fix magic grouping on date fields

Date fields have magic grouping methods to specify how to group on
them like date:month, date:weeks, date:days for example. It needs
to be handled properly since date:month is not a valid field name
but date is.

Steps to reproduce the issue:
- Go to Sales/Dashboard
- Click on My Pipeline
- Group by "Creation Month"

Basically, this can be triggred from any view which has a search
view which defines a group using the magic date grouping methods.

1 files changed, 24 insertions, 0 deletions

diff --git a/addons/web/static/tests/views/basic_model_tests.js b/addons/web/static/tests/views/basic_model_tests.js
index 53577d90e40..63214b0f2d7 100644
--- a/addons/web/static/tests/views/basic_model_tests.js
+++ b/addons/web/static/tests/views/basic_model_tests.js
@@ -956,6 +956,30 @@ QUnit.module('Views', {
         model.destroy();
     });
 
+    QUnit.test('group on date field with magic grouping method', function (assert) {
+        assert.expect(1);
+
+        this.params.fieldNames = ['foo'];
+        this.params.groupedBy = ['date:month'];
+        this.params.res_id = undefined;
+
+        var model = createModel({
+            Model: BasicModel,
+            data: this.data,
+            mockRPC: function (route, args) {
+                if (args.method === 'read_group') {
+                    assert.deepEqual(args.kwargs.fields, ['foo', 'date'],
+                        "should have correctly trimmed the magic grouping info from the field name");
+                }
+                return this._super.apply(this, arguments);
+            },
+        });
+
+        model.load(this.params);
+        model.destroy();
+    });
+
+
     QUnit.test('read group when grouped by a selection field', function (assert) {
         assert.expect(5);