fix(tests): Stabilize Windows-only Playwright e2e failures

src/frontend/tests/core/features/tweaksTest.spec.ts

@@ -11,6 +11,16 @@ test(
 
     await page.getByTestId("side_nav_options_all-templates").click();
     await page.getByRole("heading", { name: "Basic Prompting" }).click();
+    // Wait for the new-flow Loading state to clear before checking the
+    // publish button — the canvas mounts only after the flow finishes
+    // loading, which can outlast a 20s action timeout on Windows CI.
+    await page.waitForSelector('text="Loading"', {
+      state: "hidden",
+      timeout: 60000,
+    });
+    await page.waitForSelector('[data-testid="publish-button"]', {
+      timeout: 30000,
+    });
     await page.getByTestId("publish-button").click();
     await page.getByTestId("api-access-item").click();
     await page.getByTestId("api_tab_curl").click();

src/frontend/tests/core/features/user-flow-state-cleanup.spec.ts

@@ -46,7 +46,13 @@ test(
     });
     await page.getByRole("button", { name: "Sign In" }).click();
 
-    // Create User A
+    // Create User A — wait for the homepage Loading state to clear before
+    // checking mainpage_title (mainpage_title only renders after data load,
+    // which can outlast a 30s wait on slower runners like Windows CI).
+    await page.waitForSelector('text="Loading"', {
+      state: "hidden",
+      timeout: 60000,
+    });
     await page.waitForSelector('[data-testid="mainpage_title"]', {
       timeout: 30000,
     });
@@ -106,11 +112,15 @@ test(
     }
 
     await page.waitForSelector('[data-testid="modal-title"]', {
-      timeout: 3000,
+      timeout: 30000,
     });
+    await page.getByTestId("side_nav_options_all-templates").click();
     await page.getByRole("heading", { name: "Basic Prompting" }).click();
+    // Match the canvas_controls_dropdown wait used elsewhere in the suite
+    // (tests/core/features/token-usage.spec.ts, chatInputOutput.spec.ts):
+    // the new-flow canvas can take well over 30s to mount on slower runners.
     await page.waitForSelector('[data-testid="canvas_controls_dropdown"]', {
-      timeout: 30000,
+      timeout: 100000,
     });
 
     await renameFlow(page, { flowName: userAFlowName });

src/frontend/tests/core/unit/customEdgesComponent.spec.ts

@@ -16,7 +16,7 @@ test(
     await page.getByTestId("sidebar-search-input").click();
     await page.getByTestId("sidebar-search-input").fill("search api");
     await page.waitForSelector('[data-testid="searchapiSearchApi"]', {
-      timeout: 1000,
+      timeout: 10000,
     });
 
     await zoomOut(page, 3);
@@ -32,7 +32,7 @@ test(
     await page.waitForSelector(
       '[data-testid="langchain_utilitiesTool Calling Agent"]',
       {
-        timeout: 1000,
+        timeout: 10000,
       },
     );
 
@@ -75,7 +75,7 @@ test(
     await page.getByTestId("sidebar-search-input").click();
     await page.getByTestId("sidebar-search-input").fill("search api");
     await page.waitForSelector('[data-testid="searchapiSearchApi"]', {
-      timeout: 1000,
+      timeout: 10000,
     });
 
     await zoomOut(page, 3);
@@ -91,7 +91,7 @@ test(
     await page.waitForSelector(
       '[data-testid="langchain_utilitiesTool Calling Agent"]',
       {
-        timeout: 1000,
+        timeout: 10000,
       },
     );
 

src/frontend/tests/core/unit/fileUploadComponent.spec.ts

@@ -355,7 +355,7 @@ test(
         },
       );
       await expect(page.getByText(`${newTxtFile}.txt`).first()).toBeVisible({
-        timeout: 10000,
+        timeout: 30000,
       });
       await page.getByTestId(`remove-file-button-${renamedTxtFile}`).click();
 
@@ -826,7 +826,7 @@ test(
     await page.getByTestId("sidebar-search-input").click();
     await page.getByTestId("sidebar-search-input").fill("Read File");
     await page.waitForSelector('[data-testid="files_and_knowledgeRead File"]', {
-      timeout: 1000,
+      timeout: 10000,
     });
 
     // Get flow ID from URL
@@ -902,7 +902,7 @@ test(
     await page.getByTestId("sidebar-search-input").click();
     await page.getByTestId("sidebar-search-input").fill("Text Input");
     await page.waitForSelector('[data-testid="input_outputText Input"]', {
-      timeout: 1000,
+      timeout: 10000,
     });
 
     await adjustScreenView(page, { numberOfZoomOut: 3 });
@@ -932,7 +932,7 @@ test(
     await page.getByTestId("sidebar-search-input").click();
     await page.getByTestId("sidebar-search-input").fill("Text Input");
     await page.waitForSelector('[data-testid="input_outputText Input"]', {
-      timeout: 1000,
+      timeout: 10000,
     });
 
     await adjustScreenView(page, { numberOfZoomOut: 3 });
@@ -958,7 +958,7 @@ test(
     await page.getByTestId("sidebar-search-input").click();
     await page.getByTestId("sidebar-search-input").fill("Chat Output");
     await page.waitForSelector('[data-testid="input_outputChat Output"]', {
-      timeout: 1000,
+      timeout: 10000,
     });
     await page
       .getByTestId("input_outputChat Output")

src/frontend/tests/fixtures.ts

@@ -2,9 +2,29 @@
 import { test as base, expect, Page } from "@playwright/test";
 import "./playwrightCoverage";
 
+// Optional CPU throttling for reproducing race conditions seen on slower
+// runners (Windows CI). Enable with LF_CPU_THROTTLE=<rate>, e.g. 4.
+const CPU_THROTTLE_RATE = (() => {
+  const raw = process.env.LF_CPU_THROTTLE;
+  if (!raw) return 0;
+  const n = Number.parseFloat(raw);
+  return Number.isFinite(n) && n > 1 ? n : 0;
+})();
+
 // Extend test to log backend errors
 export const test = base.extend({
   page: async ({ page }, use) => {
+    if (CPU_THROTTLE_RATE > 0) {
+      try {
+        const client = await page.context().newCDPSession(page);
+        await client.send("Emulation.setCPUThrottlingRate", {
+          rate: CPU_THROTTLE_RATE,
+        });
+      } catch {
+        // Throttling is best-effort and only supported on Chromium.
+      }
+    }
+
     const errors: Array<{
       url: string;
       status: number;

src/frontend/tests/globalTeardown.ts

@@ -3,31 +3,77 @@
 import fs from "fs";
 import path from "path";
 
+const sleep = (ms: number) => new Promise((r) => setTimeout(r, ms));
+
+// On Windows, the uvicorn process can still hold SQLite file handles when
+// teardown runs. POSIX allows unlinking files with open handles; Win32 does
+// not, surfacing as EBUSY/EPERM. Retry with backoff, fall back to walking the
+// tree and removing children individually, and never throw out of teardown.
+async function removeWithRetry(target: string): Promise<boolean> {
+  const attempts = 5;
+  for (let i = 0; i < attempts; i++) {
+    try {
+      fs.rmSync(target, { recursive: true, force: true });
+      if (!fs.existsSync(target)) return true;
+    } catch (err) {
+      const code = (err as NodeJS.ErrnoException).code;
+      if (code !== "EBUSY" && code !== "EPERM" && code !== "ENOTEMPTY") {
+        throw err;
+      }
+    }
+    await sleep(200 * 2 ** i);
+  }
+  return !fs.existsSync(target);
+}
+
+function removeChildrenBestEffort(target: string): string[] {
+  const failed: string[] = [];
+  let entries: fs.Dirent[];
+  try {
+    entries = fs.readdirSync(target, { withFileTypes: true });
+  } catch {
+    return failed;
+  }
+  for (const entry of entries) {
+    const childPath = path.join(target, entry.name);
+    try {
+      fs.rmSync(childPath, { recursive: true, force: true });
+    } catch {
+      failed.push(childPath);
+    }
+  }
+  return failed;
+}
+
 export default async () => {
+  console.warn("Removing the temp database");
+  // this file is in src/frontend/tests/globalTeardown.ts
+  // temp is in src/frontend/temp
+  const tempDbPath = path.join(__dirname, "..", "temp");
+  console.warn("tempDbPath", tempDbPath);
+
+  if (!fs.existsSync(tempDbPath)) {
+    console.warn("Temp database directory does not exist, skipping removal");
+    return;
+  }
+
   try {
-    console.warn("Removing the temp database");
-    // Check if the file exists in the path
-    // this file is in src/frontend/tests/globalTeardown.ts
-    // temp is in src/frontend/temp
-    const tempDbPath = path.join(__dirname, "..", "temp");
-    console.warn("tempDbPath", tempDbPath);
-
-    // Check if the directory exists before attempting to remove it
-    if (fs.existsSync(tempDbPath)) {
-      // Remove the temp database
-      fs.rmSync(tempDbPath, { recursive: true, force: true });
-
-      // Check if the file is removed
-      if (!fs.existsSync(tempDbPath)) {
-        console.warn("Successfully removed the temp database");
-      } else {
-        console.error(
-          "Error: temp database still exists after removal attempt",
-        );
-      }
-    } else {
-      console.warn("Temp database directory does not exist, skipping removal");
+    if (await removeWithRetry(tempDbPath)) {
+      console.warn("Successfully removed the temp database");
+      return;
+    }
+
+    const stragglers = removeChildrenBestEffort(tempDbPath);
+    if (await removeWithRetry(tempDbPath)) {
+      console.warn(
+        "Successfully removed the temp database after per-file fallback",
+      );
+      return;
     }
+
+    console.warn(
+      `Temp database directory still present after retries; leaving it for the runner workspace cleanup. Files that resisted removal: ${stragglers.length}`,
+    );
   } catch (error) {
     console.error("Error while removing the temp database:", error);
   }

src/frontend/tests/utils/add-new-user-and-loggin.ts

@@ -42,13 +42,16 @@ export const addNewUserAndLogin = async (page: Page) => {
 
   await page.getByRole("button", { name: "Sign In" }).click();
 
-  await page.waitForSelector('[data-testid="mainpage_title"]', {
-    timeout: 30000,
-  });
-
-  // Wait for any loading text to disappear
+  // Wait for any loading text to disappear before checking the homepage:
+  // mainpage_title only renders after the homepage data finishes loading,
+  // and on slower runners (Windows CI) the Loading state can outlast a
+  // 30s mainpage_title wait.
   await page.waitForSelector('text="Loading"', {
     state: "hidden",
+    timeout: 60000,
+  });
+
+  await page.waitForSelector('[data-testid="mainpage_title"]', {
     timeout: 30000,
   });