Question

我知道如何编写一个从管道输入流的函数。我可以通过阅读函数的源来合理地告诉它是否能正常执行。但是，有没有任何方法可以实际测试以获得正确的行为？

我接受“测试”的任何定义......是我可以运行的一些手动测试或更自动化的。

如果你需要一个例子，假设我有一个将文本分成单词的功能。

PS> Get-Content ./warandpeace.txt | Split-Text

我如何检查它是否从流水线输入流并立即开始拆分？

Answer 1

您可以编写一个辅助函数，它可以为您提供一些指示，作为传递给它的管道项并由下一个命令处理：

function Print-Pipeline {
    param($Name, [ConsoleColor]$Color)
    begin {
        $ColorParameter = if($PSBoundParameters.ContainsKey('Color')) {
            @{ ForegroundColor = $Color }
        } else {
            @{ }
        }
    }
    process {
        Write-Host "${Name}|Before|$_" @ColorParameter
        ,$_
        Write-Host "${Name}|After|$_" @ColorParameter
    }
}

假设您有一些要测试的功能：

$Text = 'Some', 'Random', 'Text'
function CharSplit1 { $Input | % GetEnumerator }
filter CharSplit2 { $Input | % GetEnumerator }

你可以像那样测试它们：

PS> $Text |
>>> Print-Pipeline Before` CharSplit1 |
>>> CharSplit1 |
>>> Print-Pipeline After` CharSplit1
Before CharSplit1|Before|Some
Before CharSplit1|After|Some
Before CharSplit1|Before|Random
Before CharSplit1|After|Random
Before CharSplit1|Before|Text
Before CharSplit1|After|Text
After CharSplit1|Before|S
S
After CharSplit1|After|S
After CharSplit1|Before|o
o
After CharSplit1|After|o
After CharSplit1|Before|m
m
After CharSplit1|After|m
After CharSplit1|Before|e
e
After CharSplit1|After|e
After CharSplit1|Before|R
R
After CharSplit1|After|R
After CharSplit1|Before|a
a
After CharSplit1|After|a
After CharSplit1|Before|n
n
After CharSplit1|After|n
After CharSplit1|Before|d
d
After CharSplit1|After|d
After CharSplit1|Before|o
o
After CharSplit1|After|o
After CharSplit1|Before|m
m
After CharSplit1|After|m
After CharSplit1|Before|T
T
After CharSplit1|After|T
After CharSplit1|Before|e
e
After CharSplit1|After|e
After CharSplit1|Before|x
x
After CharSplit1|After|x
After CharSplit1|Before|t
t
After CharSplit1|After|t
PS> $Text |
>>> Print-Pipeline Before` CharSplit2 |
>>> CharSplit2 |
>>> Print-Pipeline After` CharSplit2
Before CharSplit2|Before|Some
After CharSplit2|Before|S
S
After CharSplit2|After|S
After CharSplit2|Before|o
o
After CharSplit2|After|o
After CharSplit2|Before|m
m
After CharSplit2|After|m
After CharSplit2|Before|e
e
After CharSplit2|After|e
Before CharSplit2|After|Some
Before CharSplit2|Before|Random
After CharSplit2|Before|R
R
After CharSplit2|After|R
After CharSplit2|Before|a
a
After CharSplit2|After|a
After CharSplit2|Before|n
n
After CharSplit2|After|n
After CharSplit2|Before|d
d
After CharSplit2|After|d
After CharSplit2|Before|o
o
After CharSplit2|After|o
After CharSplit2|Before|m
m
After CharSplit2|After|m
Before CharSplit2|After|Random
Before CharSplit2|Before|Text
After CharSplit2|Before|T
T
After CharSplit2|After|T
After CharSplit2|Before|e
e
After CharSplit2|After|e
After CharSplit2|Before|x
x
After CharSplit2|After|x
After CharSplit2|Before|t
t
After CharSplit2|After|t
Before CharSplit2|After|Text

Answer 2

向Zip函数添加一些Write-Verbose语句，然后使用Split-Text参数调用它。你应该实时看到输出。

Answer 3

啊，我有一个非常简单的解决方案。这个概念是在您正在测试的函数之前将自己的步骤插入到具有明显副作用的管道中。例如......

PS> 1..10 | %{ Write-Host $_; $_ } | function-under-test

如果你的被测功能是“坏”，你会看到1..10的所有输出两次，比如这个

1 2 3 1 2 3

如果被测功能是从管道中懒洋洋地处理项目，你会看到输出是交错的。

1 1 2 2 3 3

我如何测试PowerShell函数是否正确地从管道输入输入？

3 个答案: