pester · Der-Bayer · Sep 18, 2025
diff --git a/Scripts/PesterInterface.Tests.ps1 b/Scripts/PesterInterface.Tests.ps1
@@ -108,6 +108,21 @@ Describe 'PesterInterface' {
 			$baseMock.Data = @('pester')
 			Expand-TestCaseName $baseMock | Should -Be 'Array TestCase pester'
 		}
+		It 'Works with Array testcase - placeholder only' {
+			$baseMock.Name = '<_>'
+			$baseMock.Data = @('pester')
+			Expand-TestCaseName $baseMock | Should -Be 'pester'
+		}
+		It 'Works with Array testcase - PSCustomObject' {
+			$baseMock.Name = 'Using PropertyName: Returns <Emoji> (<Description>)'
+			$baseMock.Data = [pscustomobject]@{ Emoji = '🦒' ; Description = 'giraffe' }
+			Expand-TestCaseName $baseMock | Should -Be 'Using PropertyName: Returns 🦒 (giraffe)'
+		}
+		It 'Works with Array testcase - PSCustomObject Property' {
+			$baseMock.Name = 'Using _.PropertyName: Returns <_.Emoji> (<_.Description>)'
+			$baseMock.Data = [pscustomobject]@{ Emoji = '🦒' ; Description = 'giraffe' }
+			Expand-TestCaseName $baseMock | Should -Be 'Using _.PropertyName: Returns 🦒 (giraffe)'
+		}
 		It 'Works with Single Hashtable testcase' {
 			$baseMock.Name = 'Array TestCase <Name>'
 			$baseMock.Data = @{Name = 'pester' }
@@ -118,11 +133,47 @@ Describe 'PesterInterface' {
 			$baseMock.Data = @{Name = 'pester'; Data = 'aCoolTest' }
 			Expand-TestCaseName $baseMock | Should -Be 'Array aCoolTest TestCase pester'
 		}
-
+		It 'Works with Multiple Hashtable testcase - Property syntax' {
+			$baseMock.Name = 'Using _.PropertyName: Returns <_.Emoji> (<_.Description>)'
+			$baseMock.Data = @{ Emoji = '🦒' ; Description = 'giraffe' }
+			Expand-TestCaseName $baseMock | Should -Be 'Using _.PropertyName: Returns 🦒 (giraffe)'
+		}
+		It "Works with Multiple Hashtable testcase - dot-navigation" {
+			$baseMock.Name = 'A <animal.emoji> (<Name>) goes <Animal.Sound>'
+			$baseMock.Data = @{ Name = "cow";	Animal = @{	Sound = "Mooo";	Emoji = "🐄"}}
+			Expand-TestCaseName $baseMock | Should -Be 'A 🐄 (cow) goes Mooo'
+		}
 		It 'Works with Pester.Block' {
 			$Block = Import-Clixml $Mocks/Block.clixml
 			Expand-TestCaseName $Block | Should -Be 'Describe Nested Foreach giraffe'
 		}
+		It 'Works with Variable defined in Before-Block' -Skip {
+			$baseMock.Name = '<banana> <giraffe>'
+			# TODO dont know how to test this and get this case working
+			#$baseMock.BeforeAll = { $banana = '🍌' }
+			#$baseMock.BeforeEach = { $giraffe = '🦒' }
+			Expand-TestCaseName $baseMock | Should -Be '🍌 🦒'
+		}
+		It 'Works with Escaping in Single Quotes' {
+			$baseMock.Name = 'x: `<<_>`>'
+			$baseMock.Data = @(1)
+			Expand-TestCaseName $baseMock | Should -Be 'x: <1>'
+		}
+		It 'Works with Escaping in Single Quotes 2' {
+			$baseMock.Name = 'When x `< 4, x: <_>'
+			$baseMock.Data = @(1)
+			Expand-TestCaseName $baseMock | Should -Be 'When x < 4, x: 1'
+		}
+		It 'Works with Escaping in Double Quotes' {
+			$baseMock.Name = "x: ``<<_>``>"
+			$baseMock.Data = @(1)
+			Expand-TestCaseName $baseMock | Should -Be 'x: <1>'
+		}
+		It 'Works with Escaping in Double Quotes 2' {
+			$baseMock.Name = "When x ``< 4, x: <_>"
+			$baseMock.Data = @(1)
+			Expand-TestCaseName $baseMock | Should -Be 'When x < 4, x: 1'
+		}
 	}
 
 	Context 'Get-DurationString' {

diff --git a/Scripts/PesterTestPlugin.psm1 b/Scripts/PesterTestPlugin.psm1
@@ -149,17 +149,62 @@ function Expand-TestCaseName {
 	process {
 		[String]$Name = $Test.Name.ToString()
 
-		$Data = Merge-TestData $Test
+		$Data = ([Hashtable] (Merge-TestData $Test))
+
+		$flatData = @{}
+		foreach ($DataItem in $Data) {
+			$flatData += Flatten-Object $DataItem
+		}
 
 		# Array value was stored as _ by Merge-TestData
-		$Data.GetEnumerator().ForEach{
-			$Name = $Name -replace ('<{0}>' -f $PSItem.Key), $PSItem.Value
+		$placeholders = [regex]::Matches($Name, '(^<|[^`]<)([_\.]?[^>]*)>')
+		foreach ($placeholder in $placeholders) {
+			$match = $placeholder.Groups[2].Value
+			$replacement = ""
+			if($match.StartsWith("_.")) {
+					$replacement = $null -ne $flatData[$match] ? $flatData[$match] : $flatData[$match.Trim("_.")]
+			} else {
+					$replacement = $null -ne $flatData[$match] ? $flatData[$match] : $flatData["_." + $match]
+			}
+			$Name = $Name -replace "<(_\.)?$match>", $replacement
 		}
 
+		$Name = $Name -replace '`', ''
+
 		return $Name
 	}
 }
 
+# Inspired by https://gist.github.com/SP3269/fb5b0784bf2cede11ac3a1fa6d5ee1de
+function Flatten-Object ( $object, [string] $prefix = "" ) {
+	[CmdletBinding()]
+
+	$result = @{}
+
+	if ($null -eq $object) {
+		return @{$prefix = "null" }
+	}
+
+	$point = $prefix -eq "" ? "" : "."
+
+	switch -Regex ($object.GetType().Name) {
+		'^(Boolean|String|Int32|Int64|Float|Double|.*\[\])$' {
+			$result += @{$prefix = $object }
+		}
+		"Hashtable" {
+			$object.GetEnumerator() | ForEach-Object {
+				$result += Flatten-Object $PSItem.Value ($prefix + $point + $PSItem.Key)
+			}
+		}
+		"PSCustomObject" {
+			$(Get-Member -InputObject $object -MemberType NoteProperty).GetEnumerator() | ForEach-Object {
+				$result += Flatten-Object ($object | Select-Object -ExpandProperty $PSItem.Name) ($prefix + $point + $PSItem.Name)
+			}
+		}
+	}
+	return $result
+}
+
 function New-TestItemId {
 	<#
     .SYNOPSIS

diff --git a/sample/Tests/DataDriven.Tests.ps1 b/sample/Tests/DataDriven.Tests.ps1
@@ -0,0 +1,226 @@
+BeforeDiscovery {
+	$script:arrayOfHashtables = @(
+		@{ Emoji = '🌵' ; Description = 'cactus' }
+		@{ Emoji = '🦒' ; Description = 'giraffe' }
+		@{ Emoji = '🍎' ; Description = 'apple' }
+		@{ Emoji = '🐧' ; Description = 'penguin' }
+		@{ Emoji = '😊' ; Description = 'smiling face with smiling eyes' }
+	)
+
+	$script:arrayOfObjects = @(
+		[pscustomobject]@{ Emoji = '🌵' ; Description = 'cactus' }
+		[System.Object]@{ Emoji = '🦒' ; Description = 'giraffe' }
+		[pscustomobject]@{ Emoji = '🍎' ; Description = 'apple' }
+		[pscustomobject]@{ Emoji = '🐧' ; Description = 'penguin' }
+		[pscustomobject]@{ Emoji = '😊' ; Description = 'smiling face with smiling eyes' }
+	)
+}
+
+Describe 'Issue 247' {
+	Describe 'Template expansion' {
+		Context 'Array of hashtables' {
+			It 'Using PropertyName:   Returns <Emoji> (<Description>)' -ForEach $arrayOfHashtables {}
+			It 'Using _.PropertyName: Returns <_.Emoji> (<_.Description>)' -ForEach $arrayOfHashtables {}
+		}
+		Context 'Array of objects' {
+			It 'Using PropertyName:   Returns <Emoji> (<Description>)' -ForEach $arrayOfObjects {}
+			It 'Using _.PropertyName: Returns <_.Emoji> (<_.Description>)' -ForEach $arrayOfObjects {}
+		}
+	}
+}
+
+Describe 'Pester Documentation V5' {
+	BeforeAll {
+		Get-Module PesterDemoFunctions | Remove-Module
+		New-Module PesterDemoFunctions -ScriptBlock {
+			$emojis = @(
+				@{ Name = 'apple'; Symbol = '🍎'; Kind = 'Fruit' }
+				@{ Name = 'beaming face with smiling eyes'; Symbol = '😁'; Kind = 'Face' }
+				@{ Name = 'cactus'; Symbol = '🌵'; Kind = 'Plant' }
+				@{ Name = 'giraffe'; Symbol = '🦒'; Kind = 'Animal' }
+				@{ Name = 'pencil'; Symbol = '✏️'; Kind = 'Item' }
+				@{ Name = 'penguin'; Symbol = '🐧'; Kind = 'Animal' }
+				@{ Name = 'pensive'; Symbol = '😔'; Kind = 'Face' }
+				@{ Name = 'slightly smiling face'; Symbol = '🙂'; Kind = 'Face' }
+				@{ Name = 'smiling face with smiling eyes'; Symbol = '😊'; Kind = 'Face' }
+			) | ForEach-Object { [PSCustomObject]$_ }
+
+			function Get-Emoji ([string]$Name = '*') {
+				$script:emojis | Where-Object Name -like $Name | ForEach-Object Symbol
+			}
+
+			function Get-EmojiKind {
+				param(
+					[Parameter(Mandatory = $true, ValueFromPipeline = $true)]
+					[string]$Emoji
+				)
+				process {
+					$script:emojis | Where-Object Symbol -eq $Emoji | Foreach-Object Kind
+				}
+			}
+
+			$fruitBasket = [System.Collections.ArrayList]@('🍎', '🍌', '🥝', '🥑', '🍇', '🍐')
+
+			function Get-FruitBasket {
+				$script:fruitBasket
+			}
+
+			function Remove-FruitBasket {
+				param(
+					[Parameter(Mandatory = $true)]
+					[string]$Item
+				)
+				$script:fruitBasket.Remove($Item)
+			}
+
+			function Reset-FruitBasket {
+				$script:fruitBasket = [System.Collections.ArrayList]@('🍎', '🍌', '🥝', '🥑', '🍇', '🍐')
+			}
+		} | Import-Module
+	}
+	Context "Using -ForEach & -TestCases with hashtable" {
+		Describe "Get-Emoji" {
+			It "Returns <expected> (<name>)" -ForEach @(
+				@{ Name = "cactus"; Expected = '🌵' }
+				@{ Name = "giraffe"; Expected = '🦒' }
+				@{ Name = "apple"; Expected = '🍎' }
+				@{ Name = "pencil"; Expected = '✏️' }
+				@{ Name = "penguin"; Expected = '🐧' }
+				@{ Name = "smiling face with smiling eyes"; Expected = '😊' }
+			) {
+				Get-Emoji -Name $name | Should -Be $expected
+			}
+		}
+		Describe "Get-Emoji <name>" -ForEach @(
+			@{ Name = "cactus"; Symbol = '🌵'; Kind = 'Plant' }
+			@{ Name = "giraffe"; Symbol = '🦒'; Kind = 'Animal' }
+		) {
+			It "Returns <symbol>" {
+				Get-Emoji -Name $name | Should -Be $symbol
+			}
+
+			It "Has kind <kind>" {
+				Get-Emoji -Name $name | Get-EmojiKind | Should -Be $kind
+			}
+		}
+		Describe "Get-Emoji <name>" -ForEach @(
+			@{
+				Name   = "cactus";
+				Symbol = '🌵';
+				Kind   = 'Plant'
+				Runes  = @(
+					@{ Index = 0; Rune = 127797 }
+				)
+			}
+			@{
+				Name   = "pencil"
+				Symbol = '✏️'
+				Kind   = 'Item'
+				Runes  = @(
+					@{ Index = 0; Rune = 9999 }
+					@{ Index = 1; Rune = 65039 }
+				)
+			}
+		) {
+			It "Returns <symbol>" {
+				Get-Emoji -Name $name | Should -Be $symbol
+			}
+
+			It "Has kind <kind>" {
+				Get-Emoji -Name $name | Get-EmojiKind | Should -Be $kind
+			}
+
+			Context "Runes (each character in multibyte emoji)" {
+				It "Has rune <rune> on index <index>" -ForEach $runes {
+					$actual = @((Get-Emoji -Name $name).EnumerateRunes())
+					$actual[$index].Value | Should -Be $rune
+				}
+			}
+		}
+	}
+	Context 'Using -ForEach & -TestCases with an array' {
+		Describe "Get-FruitBasket" {
+			It "Contains <_>" -ForEach '🍎', '🍌', '🥝', '🥑', '🍇', '🍐' {
+				Get-FruitBasket | Should -Contain $_
+			}
+
+			Context "Fruit <_>" -ForEach '🍎', '🍌', '🥝', '🥑', '🍇', '🍐' {
+				It "Contains <_> by default" {
+					Get-FruitBasket | Should -Contain $_
+				}
+
+				It "Can remove <_> from the basket" {
+					Remove-FruitBasket -Item $_
+					Get-FruitBasket | Should -Not -Contain $_
+				}
+			}
+			AfterAll {
+				Reset-FruitBasket
+			}
+		}
+	}
+	Context 'Using <> templates' {
+		BeforeAll {
+			$script:apple = '🍎'
+		}
+
+		Describe "<apple>" {
+			It "<apple> <animal>" -ForEach @(
+				@{ Animal = "🐛" }
+				@{ Animal = "🐶" }
+			) {}
+		}
+		Describe "<banana>" {
+			BeforeAll {
+				$script:banana = '🍌'
+			}
+
+			BeforeEach {
+				$script:giraffe = '🦒'
+			}
+
+			It "<banana> <giraffe> <animal>" {}
+		}
+		Describe "Animals " {
+			It "<_>" -ForEach @("🐛", "🐶") {}
+		}
+	}
+	Context 'Using dot-navigation in <> template' {
+		Describe "Animals" {
+			It "A <animal.emoji> (<name>) goes <animal.sound>" -ForEach @(
+				@{
+					Name   = "cow"
+					Animal = @{
+						Sound = "Mooo"
+						Emoji = "🐄"
+					}
+				}
+				@{
+					Name   = "fox"
+					Animal = @{
+						Sound = "Ring-ding-ding-ding-dingeringeding!"
+						Emoji = "🦊"
+					}
+				}
+			) {}
+		}
+	}
+	Context 'Escaping' {
+		Describe 'with single quoted string' {
+			Describe "Fruit <_>" -ForEach "🍎", "🍐" {
+				It 'Getting <_> returns $null' {}
+			}
+			Describe 'When x `< 4, x: <_>' -ForEach @(1..4) {
+				It 'x: `<<_>`>' {}
+			}
+		}
+		Describe 'with double  quoted string' {
+			Describe "Fruit <_>" -ForEach "🍎", "🍐" {
+				It "Getting <_> returns `$null" {}
+			}
+			Describe "When x ``< 4, x: <_>" -ForEach @(1..4) {
+				It "x: ``<<_>``>" {}
+			}
+		}
+	}
+}