[FIX] web: various fixes for date and datetime in client

The field_utils date method have been modified recently, and the idea
behind those changes is that the BasicModel keeps at all time a moment
instance as its internal representation of a date or datetime.

But the parse and format methods did not properly support unset dates,
so we have to slighlty change them to support the case where their values is
not set.

addons/web/static/test/views/basic_model_tests.js

@@ -23,7 +23,7 @@ QUnit.module('Views', {
                 },
                 records: [
                     {id: 1, foo: 'blip', bar: 1, product_id: 37, category: [12], display_name: "first partner", date: "2017-01-25"},
-                    {id: 2, foo: 'gnap', bar: 2, product_id: 41, display_name: "second partner", date: "2017-01-26"},
+                    {id: 2, foo: 'gnap', bar: 2, product_id: 41, display_name: "second partner"},
                 ],
                 onchanges: {},
             },
@@ -718,9 +718,38 @@ QUnit.module('Views', {
 
     });
 
-    QUnit.test('dates are properly loaded and parsed', function (assert) {
-        assert.expect(1);
+    QUnit.test('dates are properly loaded and parsed (record)', function (assert) {
+        assert.expect(2);
 
+        var model = createModel({
+            Model: BasicModel,
+            data: this.data,
+        });
+
+        var params = {
+            fieldNames: ['date'],
+            fields: this.data.partner.fields,
+            modelName: 'partner',
+            res_id: 1,
+        };
+
+        model.load(params).then(function (resultID) {
+            var record = model.get(resultID);
+            assert.ok(record.data.date instanceof moment,
+                "fetched date field should have been formatted");
+        });
+
+        params.res_id = 2;
+
+        model.load(params).then(function (resultID) {
+            var record = model.get(resultID);
+            assert.strictEqual(record.data.date, false,
+                "unset date field should be false");
+        });
+    });
+
+    QUnit.test('dates are properly loaded and parsed (list)', function (assert) {
+        assert.expect(2);
 
         var model = createModel({
             Model: BasicModel,
@@ -737,8 +766,31 @@ QUnit.module('Views', {
         model.load(params).then(function (resultID) {
             var record = model.get(resultID);
             var firstRecord = record.data[0];
+            var secondRecord = record.data[1];
             assert.ok(firstRecord.data.date instanceof moment,
                 "fetched date field should have been formatted");
+            assert.strictEqual(secondRecord.data.date, false,
+                "if date is not set, it should be false");
+        });
+    });
+
+    QUnit.test('dates are properly loaded and parsed (default_get)', function (assert) {
+        assert.expect(1);
+
+        var model = createModel({
+            Model: BasicModel,
+            data: this.data,
+        });
+
+        var params = {
+            fieldNames: ['date'],
+            fields: this.data.partner.fields,
+            modelName: 'partner',
+        };
+
+        model.makeDefaultRecord('partner', params).then(function (resultID) {
+            var record = model.get(resultID);
+            assert.strictEqual(record.data.date, false, "date default value should be false");
         });
     });