lib/Pester/3.3.14/en-US/about_TestDrive.help.txt

TOPIC
    TestDrive

SYNOPSIS
    A PSDrive for file activity limited to the scope of a singe Describe or
    Context block.

DESCRIPTION
    A test may need to work with file operations and validate certain types of
    file activities. It is usually desirable not to perform file activity tests
    that will produce side effects outside of an individual test. Pester
    creates a PSDrive inside the user's temporary drive that is accessible via a
    names PSDrive TestDrive:. Pester will remove this drive after the test
    completes. You may use this drive to isolate the file operations of your
    test to a temporary store.

EXAMPLE
    function Add-Footer($path, $footer) {
        Add-Content $path -Value $footer
    }

    Describe "Add-Footer" {
        $testPath="TestDrive:\test.txt"
        Set-Content $testPath -value "my test text."
        Add-Footer $testPath "-Footer"
        $result = Get-Content $testPath

        It "adds a footer" {
            (-join $result).Should.Be("my test text.-Footer")
        }
    }
    
    When this test completes, the contents of the TestDrive PSDrive will
    be removed.

SEE ALSO
    Context
    Describe
    It
    about_Should