mock works with any command (not just functions) and the parameter fi…

…lters are implemented. also implemented Clear-Mock

Functions/Mock.Tests.ps1

@@ -2,7 +2,7 @@ $here = Split-Path -Parent $MyInvocation.MyCommand.Path
$sut = (Split-Path -Leaf $MyInvocation.MyCommand.Path).Replace(".Tests.", ".")
. "$here\$sut"

function FunctionUnderTest {
function FunctionUnderTest ([string]$param1=""){
    return "I am a real world test"
}

@@ -19,8 +19,31 @@ Describe "When calling Mock on existing function" {
    It "Should Invoke the mocked script" {
        $result.should.be("I am the mock test")
    }
    Clear-Mocks
}

Describe "When calling Mock on existing cmdlet" {
    Mock Get-Process {return "I am not Get-Process"}

    $result=Get-Process

    It "Should Invoke the mocked script" {
        $result.should.be("I am not Get-Process")
    }
    Clear-Mocks
}

Describe "When calling Mock on cmdlet Used by Mock" {
    Mock Invoke-Command {return "I am not Invoke-Command"}
    $result = Invoke-Command {return "yes I am"}

    It "Should Invoke the mocked script" {
        $result.should.be("I am not Invoke-Command")
    }
    Clear-Mocks
}


Describe "When calling Mock on non-existing function" {
    try{
        Mock NotFunctionUnderTest {return}
@@ -29,6 +52,29 @@ Describe "When calling Mock on non-existing function" {
    }

    It "Should throw correct error" {
        $result.Exception.Message.should.be("Could not find function NotFunctionUnderTest")
        $result.Exception.Message.should.be("Could not find command NotFunctionUnderTest")
    }
    Clear-Mocks
}

Describe "When calling Mock on existing function without matching params" {
    Mock FunctionUnderTest {return "fake results"} -parameterFilter {$param1 -eq "test"}

    $result=FunctionUnderTest "badTest"

    It "Should redirect to real function" {
        $result.should.be("I am a real world test")
    }
    Clear-Mocks
}

Describe "When calling Mock on existing function with matching params" {
    Mock FunctionUnderTest {return "fake results"} -parameterFilter {$param1 -eq "badTest"}

    $result=FunctionUnderTest "badTest"

    It "Should return mocked result" {
        $result.should.be("fake results")
    }
    Clear-Mocks
}

Functions/Mock.ps1

@@ -1,10 +1,24 @@
function Mock ([string]$function, [ScriptBlock]$mockWith, [switch]$verifiable, [HashTable]$parameterFilters = @{})
$mockTable = @{}

function Mock ([string]$commandName, [ScriptBlock]$mockWith, [switch]$verifiable, [ScriptBlock]$parameterFilter = {$True})
{
    # If verifiable, add to a verifiable hashtable
    if(!(Test-Path Function:\$function)){ Throw "Could not find function $function"}
    Rename-Item Function:\$function script:PesterIsMocking_$function
    Set-Item Function:\script:$function -value $mockWith
    # Mocked function should redirect to real function if param filters are not met
    $origCommand = (Get-Command $commandName -ErrorAction SilentlyContinue)
    if(!$origCommand){ Throw "Could not find Command $commandName"}
    $blocks = @{Mock=$mockWith; Filter=$parameterFilter}
    $mock = $mockTable.$commandName
    if(!$mock) {
        if($origCommand.CommandType -eq "Function") {
            Rename-Item Function:\$commandName script:PesterIsMocking_$commandName
        }
        $metadata=New-Object System.Management.Automation.CommandMetaData $origCommand
        $cmdLetBinding = [Management.Automation.ProxyCommand]::GetCmdletBindingAttribute($metadata)
        $params = [Management.Automation.ProxyCommand]::GetParamBlock($metadata)
        $newContent=Get-Content function:\MockPrototype
        Set-Item Function:\script:$commandName -value "$cmdLetBinding `r`n param ( $params ) `r`n$newContent"
        $mock=@{OriginalCommand=$origCommand;blocks=@($blocks)}
    } else {$mock.blocks += $blocks}
    $mockTable.$commandName = $mock
    # param filters are met, mark in the verifiable table
}

@@ -16,5 +30,20 @@ function Assert-VerifiableMocks {
function Clear-Mocks {
    # Called at the end of Describe
    # Clears the Verifiable table
    # Renames all renamed mocks back to original names
    $mockTable.Keys | % { Microsoft.PowerShell.Management\Remove-Item function:\$_ }
    $script:mockTable = @{}
    Microsoft.PowerShell.Management\Get-ChildItem Function: | ? { $_.Name.StartsWith("PesterIsMocking_") } | % {Microsoft.PowerShell.Management\Rename-Item Function:\$_ "script:$($_.Name.Replace('PesterIsMocking_', ''))"}
}

function MockPrototype {
    $functionName = $MyInvocation.MyCommand.Name
    $mock=$mockTable.$functionName
    $idx=$mock.blocks.Length
    while(--$idx -ge 0) {
        if(Microsoft.PowerShell.Core\Invoke-Command $mock.blocks[$idx].Filter) { 
            Microsoft.PowerShell.Core\Invoke-Command $mockTable.$functionName.blocks.mock
            return
        }
    }
    &($mock.OriginalCommand)
}