使用 Pester 5 和 PowerShell 7 模拟类函数 [英] Mocking class functions with Pester 5 and PowerShell 7

问题描述

有人有使用 Pester 5 和 PowerShell 7 模拟点源类函数的示例吗?

Does anyone have an example of mocking a dot-sourced class function with Pester 5 and PowerShell 7?

谢谢.

示例

Classes\MyClass.ps1:

Classes\MyClass.ps1:

class MyClass {
    [void] Run() {
        Write-Host "Class: Invoking run..."
    }
}

MyModule.psm1:

MyModule.psm1:

# Import classes
. '.\Classes\MyClass.ps1'

# Instantiate classes
$MyClass = [MyClass]::new()

# Call class function
$MyClass.Run()

推荐答案

Pester 只模拟 命令 - 而不是类或其方法.

Pester only mocks commands - not classes or their methods.

模拟"的最简单方法用于方法分派测试的 PowerShell 类是利用 PowerShell 标记所有方法 virtual 的事实，从而允许派生类覆盖它们:

The easiest way to "mock" a PowerShell class for method dispatch testing is by taking advantage of the fact that PowerShell marks all methods virtual, thereby allowing derived classes to override them:

class MockedClass : MyClass
{
  Run() { Write-host "Invoking mocked Run()"}
}

---

这种方法的好处是将输入限制为 MyClass 类型的函数仍然可以使用模拟类型:

---

The nice thing about this approach is that functions that constrain input to the MyClass type will still work with the mocked type:

function Invoke-Run
{
  param([MyClass]$Instance)

  $instance.Run()
}

$mocked = [MockedClass]::new()
Invoke-Run -Instance $mocked    # this still works because [MockedClass] derives from [MyClass]

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