Merge b343343 into 61b0bf1

src/vaadin-checkbox-group.html

@@ -81,6 +81,7 @@
        * -----------|-------------|------------
        * `disabled`   | Set when the checkbox group and its children are disabled. | :host
        * `has-label` | Set when the element has a label | :host
+       * `has-value` | Set when the element has a value | :host
        * `required` | Set when the element is required | :host
        * `invalid` | Set when the element is invalid | :host
        *
@@ -254,6 +255,13 @@
           if (value.length === 0 && this._oldValue === undefined) {
             return;
           }
+
+          if (value.length) {
+            this.setAttribute('has-value', '');
+          } else {
+            this.removeAttribute('has-value');
+          }
+
           this._oldValue = value;
           // set a flag to avoid updating loop
           this._updatingValue = true;

test/vaadin-checkbox-group_test.html

@@ -179,6 +179,18 @@
       expect(vaadinCheckboxGroup.label).to.be.equal('foo');
     });
 
+    it('should not have has-value attribute by default', () => {
+      expect(vaadinCheckboxGroup.hasAttribute('has-value')).to.be.false;
+    });
+
+    it('should toggle has-value attribute on value change', () => {
+      vaadinCheckboxGroup.value = ['2'];
+      expect(vaadinCheckboxGroup.hasAttribute('has-value')).to.be.true;
+
+      vaadinCheckboxGroup.value = [];
+      expect(vaadinCheckboxGroup.hasAttribute('has-value')).to.be.false;
+    });
+
     it('should add label to checkbox group when a label is dynamically set', () => {
       vaadinCheckboxGroup.label = 'foo';