Add merf measure script

Author: gasparnagy

Measure-CommandPerformance.ps1

@@ -0,0 +1,86 @@
+# Usage:
+# 
+# For single measurement:
+# 
+# .\Measure-CommandPerformance.ps1 -Commands @("dotnet test --no-build")
+# 
+# For standard build / test measurements:
+# 
+# $commandSetsBase = @(
+#     @{ Command = "dotnet build"; Preparation = "dotnet clean" },
+#     @{ Command = "dotnet build" },
+#     @{ Command = "dotnet test --no-build" }
+# )
+# .\Measure-CommandPerformance.ps1 -CommandSets $commandSetsBase
+# 
+# For Cucumber Messages measurements
+# 
+# $commandSetsCM = @(
+#     @{ Command = "dotnet build"; Preparation = "dotnet clean" },
+#     @{ Command = "dotnet build" },
+#     @{ Command = "dotnet test --no-build"; Preparation = '$env:REQNROLL_FORMATTERS_DISABLED = "true"' },
+#     @{ Command = "dotnet test --no-build"; Preparation = '$env:REQNROLL_FORMATTERS_DISABLED = "false"' }
+# )
+# .\Measure-CommandPerformance.ps1 -CommandSets $commandSetsCM
+param(
+    [Parameter(Mandatory = $false)]
+    [string[]]$Commands,
+    [Parameter(Mandatory = $false)]
+    [hashtable[]]$CommandSets
+)
+
+function Measure-Command {
+    param(
+        [string]$Command,
+        [string]$PreparationCommand = $null
+    )
+
+    Write-Host "Warming up: $Command"
+    # Warmup run (not measured)
+    if ($PreparationCommand) {
+        Invoke-Expression $PreparationCommand | Out-Null
+    }
+    Invoke-Expression $Command | Out-Null
+
+    $measurements = @()
+
+    for ($i = 1; $i -le 3; $i++) {
+        if ($PreparationCommand) {
+            Write-Host "  Preparation ($i/3): $PreparationCommand"
+            Invoke-Expression $PreparationCommand | Out-Null
+        }
+        Write-Host "Measuring ($i/3): $Command"
+        $sw = [System.Diagnostics.Stopwatch]::StartNew()
+        Invoke-Expression $Command | Out-Null
+        $sw.Stop()
+        $elapsed = $sw.Elapsed.TotalSeconds
+        $measurements += $elapsed
+        Write-Host ("  Run ${i}: {0:N3} seconds" -f $elapsed)
+    }
+
+    $avg = ($measurements | Measure-Object -Average).Average
+    $min = ($measurements | Measure-Object -Minimum).Minimum
+    $max = ($measurements | Measure-Object -Maximum).Maximum
+
+    Write-Host ("Summary for '$Command':")
+    Write-Host ("  Average: {0:N3} s" -f $avg)
+    Write-Host ("  Min:     {0:N3} s" -f $min)
+    Write-Host ("  Max:     {0:N3} s" -f $max)
+    Write-Host ""
+}
+
+# Backwards compatibility: If CommandSets is not given, fall back to Commands array
+if ($CommandSets -and $CommandSets.Count -gt 0) {
+    foreach ($cmdset in $CommandSets) {
+        $cmd = $cmdset.Command
+        $prep = $null
+        if ($cmdset.ContainsKey("Preparation")) {
+            $prep = $cmdset.Preparation
+        }
+        Measure-Command -Command $cmd -PreparationCommand $prep
+    }
+} else {
+    foreach ($cmd in $Commands) {
+        Measure-Command -Command $cmd
+    }
+}