Cannot index into a null array while using -ForEach

[Maciek Misztal]

I'm attempting to run pester tests from VSCode (for convenience). I've noticed that whenever I'm using -ForEach, the VSCode integration fails with : Cannot index into a null array. error. This doesn't apply to regular tests.

Pester Tests version: v2023.7.7

Pester version:

Get-Module
ModuleType Version    PreRelease Name                                ExportedCommands
---------- -------    ---------- ----                                ----------------
Manifest   7.0.0.0               Microsoft.PowerShell.Management     {Add-Content, Clear-Content, …
Manifest   7.0.0.0               Microsoft.PowerShell.Utility        {Add-Member, Add-Type, Clear-…
Script     5.5.0                 Pester                              {Add-ShouldOperator, AfterAll…
Script     0.2.0                 PowerShellEditorServices.Commands   {Clear-Host, ConvertFrom-Scri…
Binary     0.2.0                 PowerShellEditorServices.VSCode     {Close-VSCodeHtmlContentView,…

[Justin Grote]

@mmisztal1980 thanks for reporting the issue! Have you tried -TestCases instead of -Foreach?

Do you have a minimal reproduction I can look at?

[Justin Grote]

For reference, this works fine and is in my current tests:

Describe 'Describe Nested Foreach <name> <symbol>' -ForEach @(
	@{ Name = 'cactus'; Symbol = '🌵'; Kind = 'Plant' }
	@{ Name = 'giraffe'; Symbol = '🦒'; Kind = 'Animal' }
) {
	It 'Returns <symbol>' { $true }

	It 'Has kind <kind>' { $true }

	It 'Nested Hashtable TestCase <kind> <name>' { $true } -TestCases @{
		Name = 'test'
	}
	It 'Nested Array TestCase <kind> <_>' { $true } -TestCases @(
		'Test'
	)
	It 'Nested Multiple Hashtable TestCase <kind> <name> <symbol>' { $true } -TestCases @(
		@{
			Name = 'Pester1'
		}
		@{
			Name = 'Pester2'
		}
	)

	Context 'Context Nested Foreach <name> <ContextValue>' -ForEach @(
		@{ ContextValue = 'Test1' }
		@{ ContextValue = 'Test2' }
	) {
		It 'Describe Context Nested Array <name> <contextvalue> <_>' -TestCases @(
			'Test1'
			'Test2'
		) { $true }
	}
}

[Justin Grote]

@mmisztal1980 I think actually it is because you have duplicate test names because you didn't use a variable in your foreach title description. The latest build now detects this and errors appropriately. Can you try the latest prerelease?

[Maciek Misztal]

Hi Justin, I'm going to try this out today. Thanks for taking a look

[Maciek Misztal]

@JustinGrote I don't see neither a new prerelease version of Pester nor of the VS Code Pester Tests extension - where should I look?

[Maciek Misztal]

I've added to placeholders to make the test cases' names unique, however I'm still seeing the issue.

I'm attaching the test-code (the parts that I can) https://gist.github.com/mmisztal1980/35b2ec0eecdd9dce40d6d6e337b4f063

[Justin Grote]

[Justin Grote]

Your example doesn't work in normal Pester either. It looks to me like your services block either needs to be defined at script scope or in a BeforeAll

Here's an example that works for me (at least gets past the null index

BeforeAll {
  [hashtable]$SCRIPT:services = @{
    'NuGet' = 'SomeService';
    'Paket' = 'SomePaketService';
  }
}

Please check in the future that your Pester tests work fine with Invoke-Pester run inside pwsh -noprofile before filing an issue on the extension itself. Thanks!

[Maciek Misztal]

Hmmm interesting. Any idea why is this behavior occuring?

[Justin Grote]

Hmmm interesting. Any idea why is this behavior occuring?

https://pester.dev/docs/usage/discovery-and-run
https://pester.dev/docs/usage/setup-and-teardown