diff --git a/tests/browser/navigation-thread-history.spec.mjs b/tests/browser/navigation-thread-history.spec.mjs
index eb45cf5a..5b2da3ec 100644
--- a/tests/browser/navigation-thread-history.spec.mjs
+++ b/tests/browser/navigation-thread-history.spec.mjs
@@ -7,7 +7,21 @@ test("Back restores each thread visit before the previous channel", async ({
   page,
   app,
 }) => {
-  await open(page, app);
+  const beta = page
+    .getByRole("navigation", { name: "Subscribed channels" })
+    .locator('button[data-channel-id="beta"]');
+  app.relay.holdUnread();
+  try {
+    await open(page, app);
+    await expect.poll(() => app.report.unreadHolds.length).toBe(1);
+    await expect(beta).toHaveAccessibleName("Beta");
+  } finally {
+    app.relay.releaseUnread();
+  }
+  // Unread evidence changes the accessible name independently of navigation.
+  await expect(beta.getByRole("img")).toHaveAccessibleName(
+    "20 observed unread messages. Not an exact total.",
+  );
   const roots = app.histories
     .get("primary/alpha")
     .filter((row) => row.content.startsWith("Thread root"));
@@ -36,7 +50,7 @@ test("Back restores each thread visit before the previous channel", async ({
   );
   await expect(panel.getByText("Thread root 1", { exact: true })).toBeVisible();
   expect(await openThread.evaluate((node) => node.isConnected)).toBe(true);
-  await page.getByRole("button", { name: "Beta", exact: true }).click();
+  await beta.click();
   await expect(
     page.getByRole("textbox", { name: "Message #Beta", exact: true }),
   ).toBeVisible();
diff --git a/tests/browser/notifications.spec.mjs b/tests/browser/notifications.spec.mjs
index be402427..a64a3fae 100644
--- a/tests/browser/notifications.spec.mjs
+++ b/tests/browser/notifications.spec.mjs
@@ -7,6 +7,7 @@ test.use({
   readState: true,
   threadUnread: true,
   pluginFixtures: true,
+  historyCounts: { alpha: 20, beta: 1 },
 });
 
 // Only the browser's OS boundary is replaced. The built host, session,
@@ -240,12 +241,6 @@ for (const kind of ["mention", "thread reply"]) {
   }) => {
     // Model a real prior contribution in relay history, not a client-side
     // participation/readiness override. The incoming reply itself has no p tag.
-    // Keep this prior contribution inside the existing 500-event unread
-    // evidence window; the default 640-row Alpha fixture would crowd it out.
-    app.histories.set(
-      "primary/alpha",
-      app.histories.get("primary/alpha").slice(-200),
-    );
     const root =
       kind === "thread reply"
         ? app.append("primary", "beta", "My prior thread", false)