PesterによるPowerShellのテスト整備 ── 運用スクリプトを壊しにくくする実務の型

Get-Module Pester -ListAvailable |
  Sort-Object Version -Descending |
  Select-Object Name, Version, Path

Install-Module -Name Pester -Scope CurrentUser -Force -SkipPublisherCheck
Import-Module Pester
Get-Module Pester

function Get-OldLogFile {
    [CmdletBinding()]
    param(
        [Parameter(Mandatory)]
        [string] $Path,

        [int] $Days = 30,

        [string] $Filter = '*.log',

        [datetime] $Now = (Get-Date)
    )

    if (-not (Test-Path -LiteralPath $Path -PathType Container)) {
        throw "Folder not found: $Path"
    }

    $limit = $Now.AddDays(-1 * $Days)

    Get-ChildItem -LiteralPath $Path -Filter $Filter -File |
        Where-Object { $_.LastWriteTime -lt $limit } |
        Sort-Object -Property LastWriteTime |
        Select-Object FullName, Name, Length, LastWriteTime
}

BeforeAll {
    . $PSScriptRoot\Get-OldLogFile.ps1
}

Describe 'Get-OldLogFile' {
    BeforeEach {
        $script:Root = Join-Path $TestDrive 'logs'
        New-Item -ItemType Directory -Path $script:Root -Force | Out-Null

        $oldLog = Join-Path $script:Root 'old.log'
        $newLog = Join-Path $script:Root 'new.log'
        $oldTxt = Join-Path $script:Root 'old.txt'

        Set-Content -LiteralPath $oldLog -Value 'old log' -Encoding UTF8
        Set-Content -LiteralPath $newLog -Value 'new log' -Encoding UTF8
        Set-Content -LiteralPath $oldTxt -Value 'old text' -Encoding UTF8

        (Get-Item -LiteralPath $oldLog).LastWriteTime = [datetime]'2026-05-01T00:00:00'
        (Get-Item -LiteralPath $newLog).LastWriteTime = [datetime]'2026-05-31T00:00:00'
        (Get-Item -LiteralPath $oldTxt).LastWriteTime = [datetime]'2026-05-01T00:00:00'
    }

    It '指定日数より古い .log ファイルだけを返す' {
        $result = Get-OldLogFile `
            -Path $script:Root `
            -Days 30 `
            -Now ([datetime]'2026-06-01T00:00:00')

        $result | Should -HaveCount 1
        $result[0].Name | Should -Be 'old.log'
    }

    It '存在しないフォルダーでは失敗する' {
        { Get-OldLogFile -Path (Join-Path $TestDrive 'missing') } |
            Should -Throw
    }
}

Invoke-Pester -Output Detailed .\Get-OldLogFile.Tests.ps1

It 'works' {
    # ...
}

It '指定日数より古い .log ファイルだけを返す' {
    # ...
}

It 'ちょうど期限日のファイルは対象にしない' {
    # ...
}

It '存在しないフォルダーでは失敗する' {
    # ...
}

$_.LastWriteTime -lt $limit

It 'ちょうど期限日のファイルは対象にしない' {
    $border = Join-Path $script:Root 'border.log'
    Set-Content -LiteralPath $border -Value 'border log' -Encoding UTF8
    (Get-Item -LiteralPath $border).LastWriteTime = [datetime]'2026-05-02T00:00:00'

    $result = Get-OldLogFile `
        -Path $script:Root `
        -Days 30 `
        -Now ([datetime]'2026-06-01T00:00:00')

    $result.Name | Should -Not -Contain 'border.log'
}

It '後続処理で使うプロパティを返す' {
    $result = Get-OldLogFile `
        -Path $script:Root `
        -Days 30 `
        -Now ([datetime]'2026-06-01T00:00:00')

    $propertyNames = $result[0].PSObject.Properties.Name

    $propertyNames | Should -Contain 'FullName'
    $propertyNames | Should -Contain 'Name'
    $propertyNames | Should -Contain 'Length'
    $propertyNames | Should -Contain 'LastWriteTime'
}

Get-ChildItem C:\Logs -Filter *.log -File |
    Where-Object { $_.LastWriteTime -lt (Get-Date).AddDays(-30) } |
    Remove-Item -Force

function Remove-OldLogFile {
    [CmdletBinding(SupportsShouldProcess)]
    param(
        [Parameter(Mandatory)]
        [string] $Path,

        [int] $Days = 30,

        [datetime] $Now = (Get-Date)
    )

    $targets = Get-OldLogFile -Path $Path -Days $Days -Now $Now

    foreach ($target in $targets) {
        if ($PSCmdlet.ShouldProcess($target.FullName, 'Remove old log file')) {
            Remove-Item -LiteralPath $target.FullName -Force
        }
    }
}

Remove-OldLogFile -Path C:\Logs -Days 30 -WhatIf

BeforeAll {
    . $PSScriptRoot\Get-OldLogFile.ps1
    . $PSScriptRoot\Remove-OldLogFile.ps1
}

Describe 'Remove-OldLogFile' {
    It '古いログファイルに対して Remove-Item を呼ぶ' {
        Mock Get-OldLogFile {
            [pscustomobject]@{
                FullName      = 'C:\Logs\old.log'
                Name          = 'old.log'
                Length        = 10
                LastWriteTime = [datetime]'2026-05-01'
            }
        }

        Mock Remove-Item {}

        Remove-OldLogFile `
            -Path 'C:\Logs' `
            -Days 30 `
            -Now ([datetime]'2026-06-01')

        Should -Invoke Remove-Item `
            -Times 1 `
            -Exactly `
            -ParameterFilter { $LiteralPath -eq 'C:\Logs\old.log' }
    }

    It 'WhatIf では Remove-Item を呼ばない' {
        Mock Get-OldLogFile {
            [pscustomobject]@{
                FullName      = 'C:\Logs\old.log'
                Name          = 'old.log'
                Length        = 10
                LastWriteTime = [datetime]'2026-05-01'
            }
        }

        Mock Remove-Item {}

        Remove-OldLogFile `
            -Path 'C:\Logs' `
            -Days 30 `
            -Now ([datetime]'2026-06-01') `
            -WhatIf

        Should -Invoke Remove-Item -Times 0
    }
}

$limit = (Get-Date).AddDays(-30)

Get-ChildItem C:\Logs -Filter *.log -File |
    Where-Object { $_.LastWriteTime -lt $limit } |
    Remove-Item -Force

function Get-OldLogFile {
    param(
        [string] $Path,
        [int] $Days = 30,
        [datetime] $Now = (Get-Date)
    )

    $limit = $Now.AddDays(-1 * $Days)

    Get-ChildItem -LiteralPath $Path -Filter *.log -File |
        Where-Object { $_.LastWriteTime -lt $limit }
}

function Remove-OldLogFile {
    [CmdletBinding(SupportsShouldProcess)]
    param(
        [string] $Path,
        [int] $Days = 30,
        [datetime] $Now = (Get-Date)
    )

    Get-OldLogFile -Path $Path -Days $Days -Now $Now |
        ForEach-Object {
            if ($PSCmdlet.ShouldProcess($_.FullName, 'Remove old log file')) {
                Remove-Item -LiteralPath $_.FullName -Force
            }
        }
}

Describe 'Get-OldLogFile' -Tag 'Unit' {
    It '指定日数より古い .log ファイルだけを返す' {
        # TestDrive を使う速いテスト
    }
}

Describe 'Log maintenance smoke test' -Tag 'Smoke' {
    It '実際のログフォルダーを読み取れる' {
        Test-Path -LiteralPath 'C:\Logs' | Should -BeTrue
    }
}

Invoke-Pester -TagFilter Unit

Invoke-Pester -ExcludeTagFilter Slow, RequiresAdmin, Network

$ErrorActionPreference = 'Stop'

Import-Module Pester

$config = New-PesterConfiguration

$config.Run.Path = @(
    Join-Path $PSScriptRoot '..\tests'
)

$config.Run.Exit = $true
$config.Output.Verbosity = 'Detailed'

$config.TestResult.Enabled = $true
$config.TestResult.OutputFormat = 'JUnitXml'
$config.TestResult.OutputPath = Join-Path $PSScriptRoot '..\test-results.xml'

$config.CodeCoverage.Enabled = $true
$config.CodeCoverage.Path = @(
    Join-Path $PSScriptRoot '..\src'
)
$config.CodeCoverage.OutputPath = Join-Path $PSScriptRoot '..\coverage.xml'

Invoke-Pester -Configuration $config

pwsh -NoProfile -File .\tools\Invoke-ProjectTests.ps1

# 避けたい
$root = 'C:\Logs'
$limit = (Get-Date).AddDays(-30)

param(
    [string] $Path,
    [datetime] $Now = (Get-Date)
)