Bug 36774: Add cypress tests

Inside k-t-d, run:
cypress run --spec t/cypress/integration/flatpickr_spec.ts

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 46c5a51d58)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
(cherry picked from commit df53cb4e24)
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>

t/cypress/integration/flatpickr_spec.ts

@@ -0,0 +1,33 @@
+import { mount } from "@cypress/vue";
+
+const dayjs = require("dayjs");
+
+const dates = {
+    today_iso: dayjs().format("YYYY-MM-DD"),
+    today_us: dayjs().format("MM/DD/YYYY"),
+    tomorrow_iso: dayjs().add(1, "day").format("YYYY-MM-DD"),
+    tomorrow_us: dayjs().add(1, "day").format("MM/DD/YYYY"),
+};
+
+describe("Flatpickr", () => {
+    beforeEach(() => {
+        cy.login();
+        cy.title().should("eq", "Koha staff interface");
+    });
+
+    it("'Clear filter' works correctly", () => {
+        cy.visit("/cgi-bin/koha/circ/overdue.pl");
+
+        cy.get("#from+span > input").click();
+        cy.get(".flatpickr-calendar")
+            .eq(0)
+            .find("span.today")
+            .click({ force: true });
+        cy.get("#from").invoke("val").should("eq", dates["today_iso"]);
+
+        cy.get("#from+span > a").click();
+        cy.get("#from").invoke("val").should("have.length", 0);
+
+        cy.get("#from+span > input").should("exist");
+    });
+});