Interprocess pipe support (for stdout/stderr capture) (#866)

- **RAII pipe handles for child process stdout/stderr capture**: `StdoutPipeHandles` is now a proper RAII type with automatic cleanup, move semantics, and partial close support. This makes it safe to use pipes for capturing child process output without risking handle/fd leaks.

- **Optional separate stderr pipe**: `CreateProcOptions` now accepts a `StderrPipe` field so callers can capture stdout and stderr independently. When null (default), stderr shares the stdout pipe as before.

- **LogStreamListener with pluggable handler**: The TCP log stream listener accepts connections from remote processes and delivers parsed log lines through a `LogStreamHandler` interface, set dynamically via `SetHandler()`. This allows any client to receive log messages without depending on a specific console implementation.

- **TcpLogStreamSink for zen::logging**: A logging sink that forwards log messages to a `LogStreamListener` over TCP, using the native `zen::logging::Sink` infrastructure with proper thread-safe synchronization.

- **Reliable child process exit codes on Linux**: `waitpid` result handling is fixed so `ProcessHandle::GetExitCode()` returns the real exit code. `ProcessHandle::Reset()` reaps zombies directly, replacing the global `IgnoreChildSignals()` which prevented exit code collection entirely. Also fixes a TOCTOU race in `ProcessHandle::Wait()` on Linux/Mac.

- **Pipe capture test suite**: Tests covering stdout/stderr capture via pipes (both shared and separate modes), RAII cleanup, move semantics, and exit code propagation using `zentest-appstub` as the child process.

- **Service command integration tests**: Shell-based integration tests for `zen service` covering the full lifecycle (install, status, start, stop, uninstall) on all three platforms — Linux (systemd), macOS (launchd), and Windows (SCM via PowerShell).

- **Test script reorganization**: Platform-specific test scripts moved from `scripts/test_scripts/` into `scripts/test_linux/`, `test_mac/`, and `test_windows/`.

1 files changed, 353 insertions, 0 deletions

diff --git a/scripts/test_windows/service-test.ps1 b/scripts/test_windows/service-test.ps1
new file mode 100644
index 000000000..4c484c63f
--- /dev/null
+++ b/scripts/test_windows/service-test.ps1
@@ -0,0 +1,353 @@
+# Test zen service command lifecycle on Windows (SCM).
+#
+# Requires: Administrator privileges
+#
+# Usage:
+#   # From an elevated PowerShell prompt:
+#   .\scripts\test_windows\service-test.ps1 [-ZenBinary <path>]
+#
+# If -ZenBinary is not given, defaults to build\windows\x64\debug\zen.exe
+# relative to the repository root.
+
+param(
+    [string]$ZenBinary
+)
+
+$ErrorActionPreference = "Stop"
+
+$ScriptDir = Split-Path -Parent $MyInvocation.MyCommand.Path
+$RepoRoot = (Resolve-Path "$ScriptDir\..\..").Path
+
+if (-not $ZenBinary) {
+    $ZenBinary = Join-Path $RepoRoot "build\windows\x64\debug\zen.exe"
+}
+$ZenServerBinary = Join-Path (Split-Path -Parent $ZenBinary) "zenserver.exe"
+$ServiceName = "ZenServerTest-$PID"
+
+$Script:Passed = 0
+$Script:Failed = 0
+$Script:TestsRun = 0
+
+function Pass($Message) {
+    $Script:TestsRun++
+    $Script:Passed++
+    Write-Host "  PASS: $Message" -ForegroundColor Green
+}
+
+function Fail($Message, $Detail) {
+    $Script:TestsRun++
+    $Script:Failed++
+    Write-Host "  FAIL: $Message" -ForegroundColor Red
+    if ($Detail) {
+        Write-Host "        $Detail"
+    }
+}
+
+function Cleanup {
+    Write-Host ""
+    Write-Host "--- Cleanup ---"
+
+    # Stop the service if running
+    $svc = Get-Service -Name $ServiceName -ErrorAction SilentlyContinue
+    if ($svc -and $svc.Status -eq "Running") {
+        Write-Host "Stopping test service..."
+        Stop-Service -Name $ServiceName -Force -ErrorAction SilentlyContinue
+        Start-Sleep -Seconds 2
+    }
+
+    # Delete the service if it exists
+    if (Get-Service -Name $ServiceName -ErrorAction SilentlyContinue) {
+        Write-Host "Removing test service..."
+        sc.exe delete $ServiceName 2>$null | Out-Null
+    }
+
+    Write-Host ""
+    Write-Host "=============================="
+    Write-Host "  Tests run:    $Script:TestsRun"
+    Write-Host "  Passed:       $Script:Passed" -ForegroundColor Green
+    if ($Script:Failed -gt 0) {
+        Write-Host "  Failed:       $Script:Failed" -ForegroundColor Red
+    } else {
+        Write-Host "  Failed:       $Script:Failed"
+    }
+    Write-Host "=============================="
+}
+
+# ── Preflight checks ──────────────────────────────────────────────
+
+$IsAdmin = ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole(
+    [Security.Principal.WindowsBuiltInRole]::Administrator)
+
+if (-not $IsAdmin) {
+    Write-Host "Error: this test must be run from an elevated (Administrator) prompt." -ForegroundColor Red
+    exit 1
+}
+
+if (-not (Test-Path $ZenBinary)) {
+    Write-Host "Error: zen binary not found at '$ZenBinary'" -ForegroundColor Red
+    Write-Host "Build with: xmake config -m debug && xmake build zen"
+    exit 1
+}
+
+if (-not (Test-Path $ZenServerBinary)) {
+    Write-Host "Error: zenserver binary not found at '$ZenServerBinary'" -ForegroundColor Red
+    Write-Host "Build with: xmake config -m debug && xmake build zenserver"
+    exit 1
+}
+
+Write-Host "zen binary:        $ZenBinary"
+Write-Host "zenserver binary:  $ZenServerBinary"
+Write-Host "service name:      $ServiceName"
+Write-Host ""
+
+try {
+
+# ── Test: status before install (should fail) ─────────────────────
+
+Write-Host "--- Test: status before install ---"
+
+$Output = & $ZenBinary service status $ServiceName 2>&1 | Out-String
+if ($Output -match "not installed") {
+    Pass "status reports 'not installed' for non-existent service"
+} else {
+    Fail "status should report 'not installed'" "got: $Output"
+}
+
+# ── Test: install ─────────────────────────────────────────────────
+
+Write-Host "--- Test: install ---"
+
+$Output = & $ZenBinary service install $ZenServerBinary $ServiceName --allow-elevation 2>&1 | Out-String
+$ExitCode = $LASTEXITCODE
+
+if ($ExitCode -eq 0) {
+    Pass "install exits with code 0"
+} else {
+    Fail "install exits with code 0" "got exit code: $ExitCode, output: $Output"
+}
+
+$svc = Get-Service -Name $ServiceName -ErrorAction SilentlyContinue
+if ($svc) {
+    Pass "service registered in SCM"
+} else {
+    Fail "service registered in SCM"
+}
+
+# Verify service configuration
+if ($svc) {
+    $svcWmi = Get-CimInstance -ClassName Win32_Service -Filter "Name='$ServiceName'" -ErrorAction SilentlyContinue
+    if ($svcWmi -and $svcWmi.PathName -match "zenserver") {
+        Pass "service binary path contains zenserver"
+    } else {
+        Fail "service binary path contains zenserver" "got: $($svcWmi.PathName)"
+    }
+
+    if ($svcWmi -and $svcWmi.StartMode -eq "Auto") {
+        Pass "service is set to auto-start"
+    } else {
+        Fail "service is set to auto-start" "got: $($svcWmi.StartMode)"
+    }
+}
+
+# ── Test: install again (already installed, no --full) ────────────
+
+Write-Host "--- Test: install again (idempotent) ---"
+
+$Output = & $ZenBinary service install $ZenServerBinary $ServiceName --allow-elevation 2>&1 | Out-String
+$ExitCode = $LASTEXITCODE
+
+if ($ExitCode -eq 0) {
+    Pass "re-install exits with code 0"
+} else {
+    Fail "re-install exits with code 0" "got exit code: $ExitCode"
+}
+
+if ($Output -match "already installed") {
+    Pass "re-install reports service already installed"
+} else {
+    Fail "re-install reports service already installed" "got: $Output"
+}
+
+# ── Test: status after install (not yet started) ──────────────────
+
+Write-Host "--- Test: status after install (stopped) ---"
+
+$Output = & $ZenBinary service status $ServiceName 2>&1 | Out-String
+if ($Output -match "not running") {
+    Pass "status reports 'not running' for stopped service"
+} else {
+    Fail "status reports 'not running' for stopped service" "got: $Output"
+}
+
+# ── Test: start ───────────────────────────────────────────────────
+
+Write-Host "--- Test: start ---"
+
+$Output = & $ZenBinary service start $ServiceName --allow-elevation 2>&1 | Out-String
+$ExitCode = $LASTEXITCODE
+
+if ($ExitCode -eq 0) {
+    Pass "start exits with code 0"
+} else {
+    Fail "start exits with code 0" "got exit code: $ExitCode, output: $Output"
+}
+
+Start-Sleep -Seconds 2
+
+$svc = Get-Service -Name $ServiceName -ErrorAction SilentlyContinue
+if ($svc -and $svc.Status -eq "Running") {
+    Pass "service is running after start"
+
+    # ── Test: status while running ────────────────────────────────
+
+    Write-Host "--- Test: status (running) ---"
+
+    $Output = & $ZenBinary service status $ServiceName 2>&1 | Out-String
+    if ($Output -match "Running") {
+        Pass "status reports 'Running'"
+    } else {
+        Fail "status reports 'Running'" "got: $Output"
+    }
+
+    if ($Output -match "zenserver") {
+        Pass "status shows executable path"
+    } else {
+        Fail "status shows executable path" "got: $Output"
+    }
+
+    # ── Test: start again (already running) ───────────────────────
+
+    Write-Host "--- Test: start again (already running) ---"
+
+    $Output = & $ZenBinary service start $ServiceName --allow-elevation 2>&1 | Out-String
+    if ($Output -match "already running") {
+        Pass "start reports service already running"
+    } else {
+        Fail "start reports service already running" "got: $Output"
+    }
+
+    # ── Test: stop ────────────────────────────────────────────────
+
+    Write-Host "--- Test: stop ---"
+
+    $Output = & $ZenBinary service stop $ServiceName --allow-elevation 2>&1 | Out-String
+    $ExitCode = $LASTEXITCODE
+
+    if ($ExitCode -eq 0) {
+        Pass "stop exits with code 0"
+    } else {
+        Fail "stop exits with code 0" "got exit code: $ExitCode, output: $Output"
+    }
+
+    Start-Sleep -Seconds 2
+
+    $svc = Get-Service -Name $ServiceName -ErrorAction SilentlyContinue
+    if ($svc -and $svc.Status -ne "Running") {
+        Pass "service is not running after stop"
+    } else {
+        Fail "service is not running after stop"
+    }
+} else {
+    Fail "service is running after start" "(skipping start-dependent tests)"
+}
+
+# ── Test: stop when already stopped ───────────────────────────────
+
+Write-Host "--- Test: stop when already stopped ---"
+
+Stop-Service -Name $ServiceName -Force -ErrorAction SilentlyContinue
+Start-Sleep -Seconds 1
+
+$Output = & $ZenBinary service stop $ServiceName --allow-elevation 2>&1 | Out-String
+if ($Output -match "not running") {
+    Pass "stop reports 'not running' when already stopped"
+} else {
+    Fail "stop reports 'not running' when already stopped" "got: $Output"
+}
+
+# ── Test: uninstall while running (should fail) ───────────────────
+
+Write-Host "--- Test: uninstall while running (should fail) ---"
+
+& $ZenBinary service start $ServiceName --allow-elevation 2>&1 | Out-Null
+Start-Sleep -Seconds 2
+
+$svc = Get-Service -Name $ServiceName -ErrorAction SilentlyContinue
+if ($svc -and $svc.Status -eq "Running") {
+    $Output = & $ZenBinary service uninstall $ServiceName --allow-elevation 2>&1 | Out-String
+    $ExitCode = $LASTEXITCODE
+
+    if ($ExitCode -ne 0 -or $Output -match "running.*stop") {
+        Pass "uninstall refuses while service is running"
+    } else {
+        Fail "uninstall refuses while service is running" "got: exit=$ExitCode, output: $Output"
+    }
+
+    # Stop it for the real uninstall test
+    & $ZenBinary service stop $ServiceName --allow-elevation 2>&1 | Out-Null
+    Stop-Service -Name $ServiceName -Force -ErrorAction SilentlyContinue
+    Start-Sleep -Seconds 2
+} else {
+    Write-Host "  (skipped: could not start service for this test)"
+}
+
+# ── Test: uninstall ───────────────────────────────────────────────
+
+Write-Host "--- Test: uninstall ---"
+
+Stop-Service -Name $ServiceName -Force -ErrorAction SilentlyContinue
+Start-Sleep -Seconds 1
+
+$Output = & $ZenBinary service uninstall $ServiceName --allow-elevation 2>&1 | Out-String
+$ExitCode = $LASTEXITCODE
+
+if ($ExitCode -eq 0) {
+    Pass "uninstall exits with code 0"
+} else {
+    Fail "uninstall exits with code 0" "got exit code: $ExitCode, output: $Output"
+}
+
+$svc = Get-Service -Name $ServiceName -ErrorAction SilentlyContinue
+if (-not $svc) {
+    Pass "service removed from SCM after uninstall"
+} else {
+    Fail "service removed from SCM after uninstall"
+}
+
+# ── Test: status after uninstall ──────────────────────────────────
+
+Write-Host "--- Test: status after uninstall ---"
+
+$Output = & $ZenBinary service status $ServiceName 2>&1 | Out-String
+if ($Output -match "not installed") {
+    Pass "status reports 'not installed' after uninstall"
+} else {
+    Fail "status reports 'not installed' after uninstall" "got: $Output"
+}
+
+# ── Test: uninstall when not installed (idempotent) ───────────────
+
+Write-Host "--- Test: uninstall when not installed ---"
+
+$Output = & $ZenBinary service uninstall $ServiceName --allow-elevation 2>&1 | Out-String
+$ExitCode = $LASTEXITCODE
+
+if ($ExitCode -eq 0) {
+    Pass "uninstall of non-existent service exits with code 0"
+} else {
+    Fail "uninstall of non-existent service exits with code 0" "got exit code: $ExitCode"
+}
+
+if ($Output -match "not installed") {
+    Pass "uninstall reports service not installed"
+} else {
+    Fail "uninstall reports service not installed" "got: $Output"
+}
+
+} finally {
+    Cleanup
+}
+
+if ($Script:Failed -gt 0) {
+    exit 1
+}