如何使用 Pester 测试函数（如何循环 Context 块）

Question

Hi i am trying to test my functions in the module but I need to know the right syntax. Here is what i have so far.

#array of functions 
     
$functions=('Get-Values',
            'Set-Value',
            'Publish-Value')

foreach($function in $functions) 
  
Context "Test Function $functions"{
    It "$function should exist"{
        "$function" | Should Exist 
    }
}

Answer 1

First this is invalid PowerShell syntax. The foreach loop body must always be enclosed in curly braces: foreach($function in $functions) { <# loop body #> } .

Apart from that, Pester doesn't support regular loops around the structural elements like Describe , Context and It . Since Pester 5 you can use data driven tests instead:

Describe 'My Functions' {

    Context 'Test Function <name>' -ForEach @(
        @{ Name = 'Get-Values' }
        @{ Name = 'Set-Value' }
        @{ Name = 'Publish-Value' }
    ) {
        It 'should exist'  {
            Get-Command $name -EA SilentlyContinue | Should -Not -BeNullOrEmpty
        }
    }
}

Also, Should -Exist tests for existence of filesystem items only. To test existence of command, use Get-Command . The parameter -EA ( -ErrorAction ) SilentlyContinue suppresses error output from Get-Command , when command isn't found. In this case Get-Command outputs $null , so with | Should -Not -BeNullOrEmpty | Should -Not -BeNullOrEmpty we check if command exists.