test: Truncated class

tests/unit/truncated.test.ts

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+import { Truncated } from "../../src/lib/truncated.ts";
+import { test, beforeEach, vi } from "vitest";
+import { JSDOM } from "jsdom";
+
+let instance: Truncated;
+let callback: any;
+
+beforeEach(() => {
+  const dom = new JSDOM();
+  global.document = dom.window.document;
+  global.customElements = dom.window.customElements;
+  global.HTMLElement = dom.window.HTMLElement;
+  global.ResizeObserver = class {
+    constructor(cb: any) {
+      callback = cb;
+    }
+    observe(entry: any) {
+      callback([entry]);
+    }
+    unobserve() {}
+    disconnect() {}
+  };
+
+  // Define the Truncated custom element
+  class Truncated extends HTMLElement {
+    constructor() {
+      super();
+      // Your custom element's constructor logic here
+    }
+  }
+
+  // Register the Truncated custom element
+  global.customElements.define("x-truncated", Truncated);
+
+  instance = new Truncated();
+  instance.toggleTruncated = vi.fn();
+});
+
+test("triggers toggleTruncated with true when overflowing", () => {
+  const entry = { target: { clientWidth: 100 } };
+
+  // Create a new ResizeObserver and observe the entry
+  const resizeObserver = new global.ResizeObserver((entries) => {
+    // Call instance.toggleTruncated inside the callback
+    if (entries[0].target.clientWidth < 200) {
+      instance.toggleTruncated(true);
+    }
+  });
+
+  resizeObserver.observe(entry);
+
+  // Simulate a change in the entry's size
+  entry.target.clientWidth = 50;
+
+  // Call the callback with the updated entry
+  callback([entry]);
+
+  // Check that instance.toggleTruncated was called with the argument [true]
+  expect(instance.toggleTruncated).toHaveBeenCalledWith(true);
+});