perf: add Measure-InstallPerformance.ps1 baseline harness

Author: MariusStorhaug

.gitignore

@@ -18,3 +18,5 @@ outputs/*
 bin/
 obj/
 libs/
+
+scripts/perf-results.jsonl

scripts/Measure-InstallPerformance.ps1

@@ -0,0 +1,77 @@
+#Requires -Version 7.0
+[CmdletBinding()]
+[Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSAvoidUsingWriteHost', '', Justification = 'Performance script intentionally uses Write-Host')]
+[Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSReviewUnusedParameter', 'ResultsPath', Justification = 'Used via splatting')]
+param(
+    [Parameter(Mandatory)]
+    [string] $Iteration,
+
+    [string[]] $Subset = @('Roboto', 'Open Sans', 'Inter'),
+
+    [switch] $IncludeAll,
+
+    [string] $ResultsPath = (Join-Path $PSScriptRoot 'perf-results.jsonl')
+)
+
+function Invoke-Uninstall {
+    param([string[]] $Names)
+    foreach ($n in $Names) {
+        $installed = Get-Font -Scope CurrentUser -ErrorAction SilentlyContinue | Where-Object { $_.Name -like "$n*" }
+        if ($installed) {
+            Uninstall-Font -Name $installed.Name -Scope CurrentUser -ErrorAction SilentlyContinue
+        }
+    }
+}
+
+function Measure-Scenario {
+    param(
+        [string] $Name,
+        [scriptblock] $Setup,
+        [scriptblock] $Action
+    )
+    Write-Host "[$Iteration] Setup    : $Name"
+    & $Setup | Out-Null
+    [System.GC]::Collect()
+    [System.GC]::WaitForPendingFinalizers()
+    Write-Host "[$Iteration] Measure  : $Name"
+    $sw = [System.Diagnostics.Stopwatch]::StartNew()
+    $err = $null
+    try { & $Action | Out-Null } catch { $err = $_.Exception.Message }
+    $sw.Stop()
+    $obj = [pscustomobject]@{
+        Iteration  = $Iteration
+        Scenario   = $Name
+        DurationMs = [int]$sw.Elapsed.TotalMilliseconds
+        DurationS  = [math]::Round($sw.Elapsed.TotalSeconds, 2)
+        Timestamp  = (Get-Date).ToString('o')
+        Error      = $err
+        Module     = (Get-Module GoogleFonts | Select-Object -First 1 -ExpandProperty Version).ToString()
+    }
+    ($obj | ConvertTo-Json -Compress) | Add-Content -LiteralPath $ResultsPath
+    Write-Host "[$Iteration] Result   : $Name -> $($obj.DurationS)s"
+    return $obj
+}
+
+$results = @()
+
+$results += Measure-Scenario -Name 'Single-Roboto' `
+    -Setup { Invoke-Uninstall -Names 'Roboto' } `
+    -Action { Install-GoogleFont -Name 'Roboto' }
+
+$results += Measure-Scenario -Name "Subset-$($Subset -join '+')" `
+    -Setup { Invoke-Uninstall -Names $Subset } `
+    -Action { Install-GoogleFont -Name $Subset }
+
+$results += Measure-Scenario -Name 'Subset-AlreadyInstalled' `
+    -Setup { } `
+    -Action { Install-GoogleFont -Name $Subset }
+
+if ($IncludeAll) {
+    $results += Measure-Scenario -Name 'All' `
+        -Setup { } `
+        -Action { Install-GoogleFont -All }
+}
+
+Write-Host ''
+Write-Host "Summary for iteration '$Iteration':"
+$results | Format-Table -AutoSize Iteration, Scenario, DurationS, Module