Invoke-Command's Mock & Code Coverage issue

[Dexter Dhami]

Hi Everyone,

I am seeing this issue while mocking the Invoke-Command, the code coverage is missing the Scriptblock passed to the Invoke-Command.

For Example : Below is the function:

Function EnsureRemotePath {

    [CmdletBinding()]

    param(

        [Parameter(Mandatory)]

        [System.Management.Automation.Runspaces.PSSession]$session,

        [Parameter()]

        [String]$Path

    )

    $pathPresent = Invoke-Command -Session $session -ScriptBlock {Test-Path -Path $using:Path}

    if (-not $pathPresent) {

        Invoke-Command -Session $session -ScriptBlock {$null = New-Item -Path $using:Path -ItemType Directory -Force}

    }

}

Below are the tests, I have written: 

Describe "EnsureRemotePath" -Tags UnitTest {

    $Session = New-PSSession -computername localhost

Context "If the Path exists on the Remote Node" {

# Arrange

Mock -CommandName Invoke-Command -ParameterFilter { $ScriptBlock.ToString().Equals('Test-Path -Path $using:Path')} -MockWith {$True} -Verifiable

Mock -CommandName Invoke-Command -ParameterFilter { $ScriptBlock.ToString().Contains('New-Item')}  -MockWith {}

# Act

EnsureRemotePath -Session $session -path 'C:\temp'

# Assert

It 'Should call Invoke-Command to check if the path on RemotelyNode exists' {

Assert-MockCalled -CommandName Invoke-Command -ParameterFilter { $ScriptBlock.ToString().Equals('Test-Path -Path $using:Path')} -Times 1 -Exactly

Assert-VerifiableMocks

}

It 'Should not create the path as it already exists' {

Assert-MockCalled -CommandName Invoke-Command -ParameterFilter { $ScriptBlock.ToString().Contains('New-Item')}  -Times 0 -Exactly

}

}

Context "If the Path does NOT exist on the Remote Node, it gets created" {

# Arrange

Mock -CommandName Invoke-Command -ParameterFilter { $ScriptBlock.ToString().Equals('Test-Path -Path $using:Path')} -MockWith {$false} -Verifiable

Mock -CommandName Invoke-Command -ParameterFilter { $ScriptBlock.ToString().Contains('New-Item')} -MockWith {} -Verifiable

# Act

EnsureRemotePath -Session $session -path 'C:\temp'

# Assert

It 'Should  create the path.' {

Assert-MockCalled -CommandName Invoke-Command -ParameterFilter { $ScriptBlock.ToString().Contains('New-Item')} -Times 1 -Exactly

Assert-VerifiableMocks

}

}

}

Now when I invoke pester to generate code coverage then the scriptblock used with Invoke-Command are being missed.

PS>Invoke-Pester -CodeCoverage @{ Path = '.\testingpester.ps1'; Function = "EnsureRemotePath" } -TestName "EnsureRemotePath"

Describing EnsureRemotePath

   Context If the Path exists on the Remote Node

    [+] Should call Invoke-Command to check if the path on RemotelyNode exists 3.27

s

    [+] Should not create the path as it already exists 57ms

   Context If the Path does NOT exist on the Remote Node, it gets created

    [+] Should  create the path. 334ms

Tests completed in 3.66s

Passed: 3 Failed: 0 Skipped: 0 Pending: 0 Inconclusive: 0

Code coverage report:

Covered 60.00 % of 5 analyzed commands in 1 file.

Missed commands:

File              Function         Line Command                                   

----              --------         ---- -------                                   

testingpester.ps1 EnsureRemotePath   72 Test-Path -Path $using:Path               

testingpester.ps1 EnsureRemotePath   74 $null = New-Item -Path $using:Path -Ite...

Is there a way in which these missing commands showing up in the code coverage results can be unit tested ?

Regards,

Deepak

[Dave Wyatt]

You could save them as a script block (or function) and test them separately from the calls to Invoke-Command, I suppose.  When you actually pass a script block to Invoke-Command, though, it executes in a separate process that Pester can't track for coverage.

[Dexter Dhami]

Thanks Dave, Let me try that.