test(): add value outside change coverage

test/specs/external-date-change.js

@@ -0,0 +1,35 @@
+import moment from 'moment';
+
+const updatedDateCurrent = moment();
+const updatedDateWeekForward = moment().add(7, 'days');
+
+const component = {
+  template: `<div>
+      <vue-pikaday 
+        v-model="date" 
+        data-vue-pikaday 
+      ></vue-pikaday>
+      <button @click="updateDateCurrent()" data-test="update-button-current">Update date to current</button>
+      <button @click="updateDateWeekForward()" data-test="update-button-week">Update date to week from now</button>
+    </div>`,
+  methods: {
+    updateDateCurrent() {
+      this.date = updatedDateCurrent.toDate();
+    },
+    updateDateWeekForward() {
+      this.date = updatedDateWeekForward.toDate();
+    }
+  }
+};
+
+describe.only('Component', () => {
+  before(() => cy.mount(component));
+
+  it('updates Pikaday value from outside', () => {
+    cy.get('[data-test="update-button-current"]').click();
+    cy.get('[data-vue-pikaday]').as('picker').should('have.value', updatedDateCurrent.format('D MMM YYYY'));
+
+    cy.get('[data-test="update-button-week"]').click();
+    cy.get('@picker').should('have.value', updatedDateWeekForward.format('D MMM YYYY'));
+  });
+});