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Accepted
Simon Elms
Asked: 2023-09-24 17:21:08 +0800 CST

可以在 It、Before 或 After 块之外调用 Pester v5 Mock 命令吗？

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我有一些旧的 Pester v4 测试，当我尝试在 Pester v5 中运行它们时，它们失败了。

在 Pester v4 中，我读到一旦Mock被调用，它将继续应用于Describe块的其余部分，即使它是在It块内调用的。Describe因此，我会在块之外的块中调用它It，以表明它不仅仅适用于单个It块。

在 Pester v4 中有效的行为似乎在 Pester v5 中不起作用。

这是我正在编写测试的脚本 MyScriptToTest.ps1：

function Get-FirstText ()
{
    return 'Some text'
}

function Get-SecondText ()
{
    return 'Other text'
}

function Get-Text ()
{
    $a = Get-FirstText
    $b = Get-SecondText

    return "$a; $b"
}

以下是 MyScriptToTest.Tests.ps1 中的测试：

BeforeAll {
    . (Join-Path $PSScriptRoot 'MyScriptToTest.ps1')
}

Describe 'Get-FirstText' {
    It 'returns text "Some text"' {
        $result = Get-FirstText
            $result | Should -Be 'Some text'
        } 
}

Describe 'Get-Text' {
    It 'returns text "Some text; Other text"' {
        Get-Text | Should -Be 'Some text; Other text'
        } 

    Mock Get-FirstText { return 'Mock text' }
    
    It 'returns text "Mock text; Other text" after mocking Get-FirstText' {
        Get-Text | Should -Be 'Mock text; Other text'
        } 
}

Pester v5测试输出如下：

Describing Get-FirstText
  [+] returns text "Some text" when called indirectly 13ms (8ms|5ms)

Describing Get-Text
  [+] returns text "Some text; Other text" 66ms (54ms|13ms)
  [-] returns text "Mock text; Other text" after mocking Get-FirstText 42ms (41ms|1ms)
   Expected strings to be the same, but they were different.
   String lengths are both 21.
   Strings differ at index 0.
   Expected: 'Mock text; Other text'
   But was:  'Some text; Other text'
              ^
   at Get-Text | Should -Be 'Mock text; Other text', C:\...\MyScriptToTest.Tests.ps1:20
   at <ScriptBlock>, C:\...\MyScriptToTest.Tests.ps1:20
Tests completed in 565ms
Tests Passed: 2, Failed: 1, Skipped: 0 NotRun: 0

但是，如果我将Mock命令移到块中It，那么它就会起作用：

BeforeAll {
    . (Join-Path $PSScriptRoot 'MyScriptToTest.ps1')
}

Describe 'Get-FirstText' {
    It 'returns text "Some text"' {
        $result = Get-FirstText
            $result | Should -Be 'Some text'
        } 
}

Describe 'Get-Text' {
    It 'returns text "Some text; Other text"' {
        Get-Text | Should -Be 'Some text; Other text'
        }   
   
    It 'returns text "Mock text; Other text" after mocking Get-FirstText' {
        Mock Get-FirstText { return 'Mock text' }
        Get-Text | Should -Be 'Mock text; Other text'
        } 
}

我还没有弄清楚Mock在 Pester v5 中调用命令的新限制。是否仍可以在块内、块外Mock调用该命令？或者现在总是必须在块内调用它？DescribeContextItIt

powershell

1 个回答

  1. Best Answer

    文档Mock描述了 v5+ 对命令必须（现在）放置位置的更改（添加了重点）：

    模拟在其所在的整体Describe/Context位置中不再有效。相反，它们将默认为它们所在的块。

    也就是说，直接Mock放置在一个或多个命令内部的命令（如您问题中的代码中所示）现在实际上被忽略了。DescribeContext

    详细说明：在Pester v5+中，为了使Mock语句有效，必须将其放置在以下构造之一内：

    • BeforeAll在命令内部，因此适用于同一范围内的所有测试。

      • 命令BeforeAll可以直接放置在Describe命令内，或者 - 为了更细粒度的控制 - 放置在嵌套Context命令内。

    • 在单个It命令内，在这种情况下它仅适用于该测试。

    在您的代码上下文中，这意味着：

    Context-级别Mock：

    Describe 'Get-Text' {
    It 'returns text "Some text; Other text"' {
        Get-Text | Should -Be 'Some text; Other text'
        } 

    Context 'With Mock' {

      BeforeAll {
        # Placing the Mock here works, and makes it take effect
        # for all tests in this context.
        Mock Get-FirstText { return 'Mock text' }
      }

      It 'returns text "Mock text; Other text" after mocking Get-FirstText' {
          Get-Text | Should -Be 'Mock text; Other text'
          } 

      # ... potentially more `It` commands to which the Mock applies.
    }
}

    It-级别Mock：

    Describe 'Get-Text' {
    It 'returns text "Some text; Other text"' {
        Get-Text | Should -Be 'Some text; Other text'
        } 

    
    It 'returns text "Mock text; Other text" after mocking Get-FirstText' {
        # Placing the Mock here works, and makes it take effect
        # for this specific test only.
        Mock Get-FirstText { return 'Mock text' }
        Get-Text | Should -Be 'Mock text; Other text'
        } 
}
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