test: add easings.ts test suite

components/_util/__tests__/easings.test.js

@@ -0,0 +1,12 @@
+import { easeInOutCubic } from '../easings';
+
+describe('Test easings', () => {
+  it('easeInOutCubic return value', () => {
+    const nums = [];
+    for (let index = 0; index < 5; index++) {
+      nums.push(easeInOutCubic(index, 1, 5, 4));
+    }
+
+    expect(nums).toEqual([1, 1.25, 3, 4.75, 5]);
+  });
+});