Pester 5 - 在嵌套循环中访问多个变量

Question

I am converting Pester tests from V4 to V5 and in line with the best practices, moving the loops from foreach() to Describe -ForEach{} . The tests are a standard set that checks if each function has comment based help and this requires multiple nested loops.

This question is similar to Pester 5 variable scoping and Working with nested foreach and I have referred to Data Driven Tests , but my problem goes deeper as firstly, I need multiple levels of nested loops and secondly, I need access to multiple variables. The first variable $helpParameterNames is used by the loop and the value of each row is checked to see if it exists in the second variable $parameterNames

V4 In V4, the arrays are accessible throughout the whole set of Describe/Context/It blocks so when I get to the last foreach loop, both $helpParameterNames and $parameterNames are accessible.

$commands = Get-Command -Module ModuleName

foreach ($command in $commands) {
    $commandName = $command.Name
    $help = Get-Help $commandName -ErrorAction SilentlyContinue
    
    Describe "Test help for $commandName" -Tag Help {
        
      <It Tests Removed>
        
        Context "Test parameter help for $commandName" {            
            $common = 'Debug', 'ErrorAction', 'ErrorVariable', 'InformationAction', 'InformationVariable', 'OutBuffer', 'OutVariable', 'PipelineVariable', 'Verbose', 'WarningAction', 'WarningVariable'
            $parameters = $command.ParameterSets.Parameters | Sort-Object -Property Name -Unique | Where-Object Name -notin $common
            $parameterNames = $parameters.Name
            $helpParameterNames = $help.Parameters.Parameter.Name | Sort-Object -Unique
            
            foreach ($parameter in $parameters) {
                $parameterName = $parameter.Name
                $parameterHelp = $help.parameters.parameter | Where-Object Name -EQ $parameterName               
                
                <It Tests Removed>
            }
            
            foreach ($helpParm in $helpParameterNames) {
                It "Should find parameter $helpParm in the function" {
                    $helpParm -in $parameterNames | Should Be $true
                }
            }
        }
    }

V5 In V5 as the setup code has to be defined in the BeforeDiscovery block, I can't get it to be available in the sub-blocks automatically. I can make it accessible by passing the array into the -ForEach as a HashTable, but then it will treat it as 1 object and not iterate over it, which is fine for $help , but not for $helpParameterNames

BeforeDiscovery {
    $commands = Get-Command -Module ModuleName
}

Describe "Help Rules" -Tags Build, Help -ForEach $commands {
    BeforeDiscovery {
        $commandName = $_.Name

        $common = 'Debug', 'ErrorAction', 'ErrorVariable', 'InformationAction', 'InformationVariable', 'OutBuffer', 'OutVariable', 'PipelineVariable', 'Verbose', 'WarningAction', 'WarningVariable'
        $parameters = (Get-Command $commandName).ParameterSets.Parameters | Where-Object -Property Name -NotIn $common | Sort-Object -Property Name -Unique
        $parameterNames = $parameters.Name
        $help = Get-Help $commandName -Full -ErrorAction SilentlyContinue
    }

    Context "General Rules for $commandName" -ForEach @{help = $help} {

        <It Tests Removed>

        Describe "Parameter Rules for <parameter.Name>" -Tags Help, Parameter -ForEach $parameters {
        
            BeforeAll {
                $parameter = $_.parameters
                $helpParameterNames = $help.Parameters.Parameter.Name | Sort-Object -Unique
                $parameterHelp = $help.parameters.parameter | Where-Object Name -EQ $parameter.Name
            }

            <It Tests Removed>
        }

        It "Should find parameter <helpParameter> in the function" -Tag Help, Parameter -ForEach $helpParameterNames {
            
            BeforeAll {
                $helpParameter = $_
            }

            $helpParameter -in $parameterNames | Should -BeTrue
        }
    }

How do I get the last -ForEach to have access to both $parameterNames from the BeforeDiscovery block and also $helpParameterNames from the parent loop?

Answer 1

This is a unique situation and the solution is that some code has to be repeated both in BeforeDiscovery and BeforeAll . Adding the code to BeforeDiscovery means that it can be used in the Context -ForEach and adding the code to BeforeAll means that it is accessible as a single object inside the child Describe blocks.

Describe "Help Rules" -Tags Build, Help -ForEach $commands {

    BeforeDiscovery {
        $common = 'Debug', 'ErrorAction', 'ErrorVariable', 'InformationAction', 'InformationVariable', 'OutBuffer', 'OutVariable', 'PipelineVariable', 'Verbose', 'WarningAction', 'WarningVariable'
        $parameters = (Get-Command $_.Name).ParameterSets.Parameters | Where-Object -Property Name -NotIn $common | Sort-Object -Property Name -Unique
        $help = Get-Help $_.Name -Full -ErrorAction SilentlyContinue
        $helpParameterNames = $help.Parameters.Parameter.Name | Sort-Object -Unique
    }
    
    BeforeAll {
        $commandName = $_.Name

        $help = Get-Help $commandName -Full -ErrorAction SilentlyContinue
        $helpParameterNames = $help.Parameters.Parameter.Name | Sort-Object -Unique
        
        #Define this both in BeforeDiscovery and BeforeAll as it is needed both in the ForEach and also as an array
        $common = 'Debug', 'ErrorAction', 'ErrorVariable', 'InformationAction', 'InformationVariable', 'OutBuffer', 'OutVariable', 'PipelineVariable', 'Verbose', 'WarningAction', 'WarningVariable'
        $parameters = (Get-Command $_.Name).ParameterSets.Parameters | Where-Object -Property Name -NotIn $common | Sort-Object -Property Name -Unique
        $parameterNames = $parameters.Name
    }

    Context "General Rules for <commandName>" -ForEach $parameters {