From af251584acb3330f77898f3b855e75cba190a394 Mon Sep 17 00:00:00 2001
From: Yury Semikhatsky <yurys@chromium.org>
Date: Wed, 28 Oct 2026 10:42:26 -0700
Subject: [PATCH] devops(ci): run Windows tests at normal I/O priority

The Windows runner starts steps at I/O priority Low. The driver and the
browsers inherit it, and Firefox storage flushes stall until tests time out.
Reset the test steps to Normal, as microsoft/playwright#43707 does upstream.
---
 .github/workflows/ci.yml      | 32 ++++++++++++++++++-------
 scripts/windows-normal-io.ps1 | 44 +++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+), 8 deletions(-)
 create mode 100644 scripts/windows-normal-io.ps1

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a3aff2aed..e48cb0749 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -127,21 +127,31 @@ jobs:
       id: install
       run: python -m playwright install --with-deps ${{ matrix.browser }}
     - name: Common Tests
-      run: pytest tests/common --browser=${{ matrix.browser }}
+      run: |
+        ${{ runner.os == 'Windows' && '. ./scripts/windows-normal-io.ps1' || '' }}
+        pytest tests/common --browser=${{ matrix.browser }}
     - name: Test Reference count
-      run: pytest tests/test_reference_count_async.py --browser=${{ matrix.browser }}
+      run: |
+        ${{ runner.os == 'Windows' && '. ./scripts/windows-normal-io.ps1' || '' }}
+        pytest tests/test_reference_count_async.py --browser=${{ matrix.browser }}
     - name: Test Wheel Installation
-      run: pytest tests/test_installation.py --browser=${{ matrix.browser }}
+      run: |
+        ${{ runner.os == 'Windows' && '. ./scripts/windows-normal-io.ps1' || '' }}
+        pytest tests/test_installation.py --browser=${{ matrix.browser }}
     - name: Test Sync API
       if: runner.os != 'Linux'
-      run: pytest tests/sync --browser=${{ matrix.browser }} -n ${{ env.WORKERS }} -p pytest_dot_reporter -rfE --color=yes
+      run: |
+        ${{ runner.os == 'Windows' && '. ./scripts/windows-normal-io.ps1' || '' }}
+        pytest tests/sync --browser=${{ matrix.browser }} -n ${{ env.WORKERS }} -p pytest_dot_reporter -rfE --color=yes
     - name: Test Sync API
       if: runner.os == 'Linux'
       run: xvfb-run --auto-servernum --server-args="-screen 0 1280x960x24" pytest tests/sync --browser=${{ matrix.browser }} -n ${{ env.WORKERS }} -p pytest_dot_reporter -rfE --color=yes
     - name: Test Async API
       # Also after a failed sync step: the two suites report on their own.
       if: ${{ !cancelled() && steps.install.outcome == 'success' && runner.os != 'Linux' }}
-      run: pytest tests/async --browser=${{ matrix.browser }} -n ${{ env.WORKERS }} -p pytest_dot_reporter -rfE --color=yes
+      run: |
+        ${{ runner.os == 'Windows' && '. ./scripts/windows-normal-io.ps1' || '' }}
+        pytest tests/async --browser=${{ matrix.browser }} -n ${{ env.WORKERS }} -p pytest_dot_reporter -rfE --color=yes
     - name: Test Async API
       if: ${{ !cancelled() && steps.install.outcome == 'success' && runner.os == 'Linux' }}
       run: xvfb-run --auto-servernum --server-args="-screen 0 1280x960x24" pytest tests/async --browser=${{ matrix.browser }} -n ${{ env.WORKERS }} -p pytest_dot_reporter -rfE --color=yes
@@ -187,17 +197,23 @@ jobs:
       id: install
       run: python -m playwright install ${{ matrix.browser-channel }} --with-deps
     - name: Common Tests
-      run: pytest tests/common --browser=chromium --browser-channel=${{ matrix.browser-channel }}
+      run: |
+        ${{ runner.os == 'Windows' && '. ./scripts/windows-normal-io.ps1' || '' }}
+        pytest tests/common --browser=chromium --browser-channel=${{ matrix.browser-channel }}
     - name: Test Sync API
       if: runner.os != 'Linux'
-      run: pytest tests/sync --browser=chromium --browser-channel=${{ matrix.browser-channel }} -n ${{ env.WORKERS }} -p pytest_dot_reporter -rfE --color=yes
+      run: |
+        ${{ runner.os == 'Windows' && '. ./scripts/windows-normal-io.ps1' || '' }}
+        pytest tests/sync --browser=chromium --browser-channel=${{ matrix.browser-channel }} -n ${{ env.WORKERS }} -p pytest_dot_reporter -rfE --color=yes
     - name: Test Sync API
       if: runner.os == 'Linux'
       run: xvfb-run --auto-servernum --server-args="-screen 0 1280x960x24" pytest tests/sync --browser=chromium --browser-channel=${{ matrix.browser-channel }} -n ${{ env.WORKERS }} -p pytest_dot_reporter -rfE --color=yes
     - name: Test Async API
       # Also after a failed sync step: the two suites report on their own.
       if: ${{ !cancelled() && steps.install.outcome == 'success' && runner.os != 'Linux' }}
-      run: pytest tests/async --browser=chromium --browser-channel=${{ matrix.browser-channel }} -n ${{ env.WORKERS }} -p pytest_dot_reporter -rfE --color=yes
+      run: |
+        ${{ runner.os == 'Windows' && '. ./scripts/windows-normal-io.ps1' || '' }}
+        pytest tests/async --browser=chromium --browser-channel=${{ matrix.browser-channel }} -n ${{ env.WORKERS }} -p pytest_dot_reporter -rfE --color=yes
     - name: Test Async API
       if: ${{ !cancelled() && steps.install.outcome == 'success' && runner.os == 'Linux' }}
       run: xvfb-run --auto-servernum --server-args="-screen 0 1280x960x24" pytest tests/async --browser=chromium --browser-channel=${{ matrix.browser-channel }} -n ${{ env.WORKERS }} -p pytest_dot_reporter -rfE --color=yes
diff --git a/scripts/windows-normal-io.ps1 b/scripts/windows-normal-io.ps1
new file mode 100644
index 000000000..f1308b638
--- /dev/null
+++ b/scripts/windows-normal-io.ps1
@@ -0,0 +1,44 @@
+# Dot-source at the start of a Windows test step: the self-hosted runner starts steps at
+# I/O priority Low, which the driver and the browsers inherit, and Firefox storage flushes
+# then stall until tests time out. See https://github.com/microsoft/playwright/issues/43704.
+
+$ErrorActionPreference = 'Stop'
+
+Add-Type -TypeDefinition @'
+using System;
+using System.Runtime.InteropServices;
+
+public static class TestProcessIOPriority {
+    [DllImport("ntdll.dll")]
+    public static extern int NtSetInformationProcess(
+        IntPtr process, int informationClass, ref int information, int size);
+
+    [DllImport("ntdll.dll")]
+    public static extern int NtQueryInformationProcess(
+        IntPtr process, int informationClass, out int information, int size, out int length);
+}
+'@
+
+$priority = 0
+$length = 0
+$status = [TestProcessIOPriority]::NtQueryInformationProcess(
+    [IntPtr](-1), 33, [ref]$priority, 4, [ref]$length)
+if ($status -ne 0) {
+    throw ('Reading I/O priority failed: NTSTATUS 0x{0:X8}' -f $status)
+}
+$inheritedPriority = $priority
+$priority = 2
+$status = [TestProcessIOPriority]::NtSetInformationProcess(
+    [IntPtr](-1), 33, [ref]$priority, 4)
+if ($status -ne 0) {
+    throw ('Setting normal I/O priority failed: NTSTATUS 0x{0:X8}' -f $status)
+}
+$status = [TestProcessIOPriority]::NtQueryInformationProcess(
+    [IntPtr](-1), 33, [ref]$priority, 4, [ref]$length)
+if ($status -ne 0) {
+    throw ('Reading I/O priority failed: NTSTATUS 0x{0:X8}' -f $status)
+}
+if ($priority -ne 2) {
+    throw "Expected normal I/O priority (2), got $priority"
+}
+Write-Host "Test launcher I/O priority: $inheritedPriority -> $priority (Normal)"