fix(slider): Add two test cases to cover give default value to step for discrete slider (#1262)

Author: yeelan0319

test/unit/mdc-slider/foundation.test.js

@@ -117,6 +117,21 @@ test('#init checks if slider is discrete and if display track markers', () => {
   raf.restore();
 });
 
+test('#init sets step to one if slider is discrete but step is zero', () => {
+  const {foundation, mockAdapter} = setupTest();
+  const raf = createMockRaf();
+
+  td.when(mockAdapter.computeBoundingRect()).thenReturn({width: 100, left: 200});
+  td.when(mockAdapter.hasClass(cssClasses.IS_DISCRETE)).thenReturn(true);
+  foundation.init();
+
+  raf.flush();
+
+  assert.equal(foundation.getStep(), 1);
+
+  raf.restore();
+});
+
 test('#init performs an initial layout of the component', () => {
   const {foundation, mockAdapter} = setupTest();
   const raf = createMockRaf();

test/unit/mdc-slider/mdc-slider.test.js

@@ -22,7 +22,7 @@ import td from 'testdouble';
 import {createMockRaf} from '../helpers/raf';
 import {TRANSFORM_PROP} from './helpers';
 
-import {strings} from '../../../packages/mdc-slider/constants';
+import {cssClasses, strings} from '../../../packages/mdc-slider/constants';
 import {MDCSlider} from '../../../packages/mdc-slider';
 
 suite('MDCSlider');
@@ -149,14 +149,23 @@ test('#initialSyncWithDOM adds an aria-valuemax attribute if not present', () =>
   assert.equal(root.getAttribute('aria-valuemax'), String(component.max));
 });
 
-test('#initialSyncWithDOM syncs the value property with aria-valuenow', () => {
+test('#initialSyncWithDOM syncs the value property with aria-valuenow for continuous slider', () => {
   const root = getFixture();
   root.setAttribute('aria-valuenow', '30');
 
   const component = new MDCSlider(root);
   assert.equal(component.value, 30);
 });
 
+test('#initialSyncWithDOM syncs the value property with aria-valuenow for discrete slider', () => {
+  const root = getFixture();
+  root.classList.add(cssClasses.DISCRETE);
+  root.setAttribute('aria-valuenow', '30');
+
+  const component = new MDCSlider(root);
+  assert.equal(component.value, 30);
+});
+
 test('#initialSyncWithDOM adds an aria-valuenow attribute if not present', () => {
   const root = getFixture();
   root.removeAttribute('aria-valuenow');