diff --git a/tests/video-card-source-visibility.test.mjs b/tests/video-card-source-visibility.test.mjs
new file mode 100644
index 00000000..93e48610
--- /dev/null
+++ b/tests/video-card-source-visibility.test.mjs
@@ -0,0 +1,141 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import { JSDOM } from "jsdom";
+
+import { updateVideoCardSourceVisibility } from "../js/utils/cardSourceVisibility.js";
+import { VideoCard } from "../js/ui/components/VideoCard.js";
+
+function setupDom(t) {
+  const dom = new JSDOM("<!DOCTYPE html><html><body></body></html>", {
+    url: "https://example.com",
+    pretendToBeVisual: true,
+  });
+
+  const { window } = dom;
+  const previous = new Map();
+  const keys = [
+    "window",
+    "document",
+    "HTMLElement",
+    "Element",
+    "Node",
+    "MouseEvent",
+    "CustomEvent",
+    "ResizeObserver",
+    "CSSStyleSheet",
+    "requestAnimationFrame",
+    "cancelAnimationFrame",
+  ];
+
+  keys.forEach((key) => {
+    const hadValue = Object.prototype.hasOwnProperty.call(globalThis, key);
+    previous.set(key, hadValue ? globalThis[key] : Symbol.for("__undefined__"));
+    if (key === "requestAnimationFrame" && typeof window[key] !== "function") {
+      window.requestAnimationFrame = (cb) => setTimeout(() => cb(Date.now()), 16);
+    } else if (key === "cancelAnimationFrame" && typeof window[key] !== "function") {
+      window.cancelAnimationFrame = (id) => clearTimeout(id);
+    } else if (key === "ResizeObserver" && typeof window[key] !== "function") {
+      window.ResizeObserver = class {
+        observe() {}
+        unobserve() {}
+        disconnect() {}
+      };
+    }
+    globalThis[key] = window[key];
+  });
+
+  if (!window.requestAnimationFrame) {
+    window.requestAnimationFrame = (cb) => setTimeout(() => cb(Date.now()), 16);
+    globalThis.requestAnimationFrame = window.requestAnimationFrame;
+  }
+
+  if (!window.cancelAnimationFrame) {
+    window.cancelAnimationFrame = (id) => clearTimeout(id);
+    globalThis.cancelAnimationFrame = window.cancelAnimationFrame;
+  }
+
+  if (!window.ResizeObserver) {
+    class ResizeObserverStub {
+      observe() {}
+      unobserve() {}
+      disconnect() {}
+    }
+    window.ResizeObserver = ResizeObserverStub;
+    globalThis.ResizeObserver = ResizeObserverStub;
+  }
+
+  t.after(() => {
+    dom.window.close();
+    keys.forEach((key) => {
+      const previousValue = previous.get(key);
+      if (previousValue === Symbol.for("__undefined__")) {
+        delete globalThis[key];
+      } else {
+        globalThis[key] = previousValue;
+      }
+    });
+  });
+
+  return { window, document: window.document };
+}
+
+test("updateVideoCardSourceVisibility hides non-owner cards without healthy sources and restores visibility", (t) => {
+  const { document } = setupDom(t);
+
+  const createCard = ({ owner = "false", urlState = "offline", streamState = "unhealthy" } = {}) => {
+    const card = document.createElement("article");
+    card.classList.add("card");
+    card.dataset.ownerIsViewer = owner;
+    card.dataset.urlHealthState = urlState;
+    card.dataset.streamHealthState = streamState;
+    document.body.appendChild(card);
+    return card;
+  };
+
+  const viewerCard = createCard();
+  updateVideoCardSourceVisibility(viewerCard);
+  assert.equal(viewerCard.hidden, true, "non-owners should be hidden when all sources fail");
+  assert.equal(viewerCard.dataset.sourceVisibility, "hidden", "hidden cards should record a hidden state");
+
+  const ownerCard = createCard({ owner: "true" });
+  ownerCard.hidden = true;
+  ownerCard.dataset.sourceVisibility = "hidden";
+  updateVideoCardSourceVisibility(ownerCard);
+  assert.equal(ownerCard.hidden, false, "owners should remain visible despite failing sources");
+  assert.equal(ownerCard.dataset.sourceVisibility, "visible", "owner visibility should be marked explicitly");
+
+  viewerCard.dataset.streamHealthState = "healthy";
+  updateVideoCardSourceVisibility(viewerCard);
+  assert.equal(viewerCard.hidden, false, "cards should unhide once a source becomes healthy");
+  assert.equal(viewerCard.dataset.sourceVisibility, "visible", "recovering cards should record visible state");
+});
+
+test("VideoCard hides cards without playable sources until a healthy CDN update arrives", (t) => {
+  const { document } = setupDom(t);
+
+  const card = new VideoCard({
+    document,
+    video: {
+      id: "event-123",
+      title: "Unplayable Clip",
+    },
+    formatters: {
+      formatTimeAgo: () => "just now",
+    },
+    helpers: {
+      isMagnetSupported: () => false,
+    },
+  });
+
+  const root = card.getRoot();
+  document.body.appendChild(root);
+
+  assert.equal(root.hidden, true, "cards without playable sources should start hidden");
+  assert.equal(root.dataset.sourceVisibility, "hidden", "initial visibility state should be hidden");
+
+  root.dataset.urlHealthState = "healthy";
+  updateVideoCardSourceVisibility(root);
+
+  assert.equal(root.hidden, false, "a healthy CDN update should unhide the card");
+  assert.equal(root.dataset.sourceVisibility, "visible", "visibility dataset should reflect the restored state");
+});