test(app): cover large stacked review tree

Author: Hona

packages/app/e2e/regression/review-terminal-stacked.spec.ts

@@ -6,6 +6,12 @@ const directory = "C:/OpenCode/ReviewTerminalStacked"
 const projectID = "proj_review_terminal_stacked"
 const sessionID = "ses_review_terminal_stacked"
 const title = "Review terminal stacked"
+const branchDiffs = [
+  fileDiff(".github/actions/setup-bun/action.yml", 7),
+  ...Array.from({ length: 2_739 }, (_, index) =>
+    fileDiff(`src/branch/generated-${String(index).padStart(4, "0")}.ts`, 100),
+  ),
+]
 
 test("keeps the review tree and terminal sized when both panels are open", async ({ page }) => {
   await page.setViewportSize({ width: 1400, height: 900 })
@@ -41,18 +47,26 @@ test("keeps the review tree and terminal sized when both panels are open", async
         time: { created: 1700000000000, updated: 1700000000000 },
       },
     ],
-    vcsDiff: [
-      {
-        file: "src/example.ts",
-        additions: 1,
-        deletions: 1,
-        status: "modified",
-        patch:
-          "diff --git a/src/example.ts b/src/example.ts\n--- a/src/example.ts\n+++ b/src/example.ts\n@@ -1 +1 @@\n-export const value = 'before'\n+export const value = 'after'\n",
-      },
-    ],
     pageMessages: () => ({ items: [] }),
   })
+  await page.route(/\/vcs(?:\?.*)?$/, (route) =>
+    route.fulfill({
+      status: 200,
+      contentType: "application/json",
+      body: JSON.stringify({ branch: "review-pane-performance", default_branch: "dev" }),
+    }),
+  )
+  await page.route("**/vcs/diff**", (route) =>
+    route.fulfill({
+      status: 200,
+      contentType: "application/json",
+      body: JSON.stringify(
+        new URL(route.request().url()).searchParams.get("mode") === "branch"
+          ? branchDiffs
+          : [fileDiff("src/git.ts", 1)],
+      ),
+    }),
+  )
   await page.route("**/pty", (route) =>
     route.fulfill({
       status: 200,
@@ -71,11 +85,22 @@ test("keeps the review tree and terminal sized when both panels are open", async
   await page.goto(`/${base64Encode(directory)}/session/${sessionID}`)
   await expectSessionTitle(page, title)
   await page.getByRole("button", { name: "Toggle review" }).click()
-  await expect(page.getByRole("button", { name: "example.ts" })).toBeVisible()
+  await expect(page.getByRole("button", { name: "git.ts" })).toBeVisible()
 
   await page.keyboard.press("Control+Backquote")
   await expect(page.locator("#terminal-panel")).toBeVisible()
-  await expect(page.getByRole("button", { name: "example.ts" })).toBeVisible()
+  // Terminal activation retries focus through 240ms; let that settle before opening the mode select.
+  await page.waitForTimeout(300)
+  await page.getByRole("button", { name: "Git changes" }).click()
+  await page.getByRole("option", { name: "Branch changes" }).click()
+  await expect(page.getByRole("tab", { name: "Review 2740" })).toBeVisible()
+  await expect(page.getByRole("button", { name: "action.yml" })).toBeVisible()
+
+  const tree = page.locator('#review-panel [data-component="file-tree-v2"]')
+  await expect(tree).toHaveAttribute("data-total-rows", "2745")
+  const renderedRows = await tree.locator('[data-slot="file-tree-v2-row"]').count()
+  expect(renderedRows).toBeGreaterThan(0)
+  expect(renderedRows).toBeLessThanOrEqual(60)
 
   const geometry = await page.evaluate(() => {
     const review = document.querySelector<HTMLElement>("#review-panel")!
@@ -96,3 +121,13 @@ test("keeps the review tree and terminal sized when both panels are open", async
 function base64Encode(value: string) {
   return Buffer.from(value, "utf8").toString("base64").replace(/\+/g, "-").replace(/\//g, "_").replace(/=/g, "")
 }
+
+function fileDiff(file: string, additions: number) {
+  return {
+    file,
+    additions,
+    deletions: 0,
+    status: "modified",
+    patch: `diff --git a/${file} b/${file}\n--- a/${file}\n+++ b/${file}\n@@ -1 +1 @@\n-export const value = 'before'\n+export const value = 'after'\n`,
+  }
+}