-HaveParameter: DefaultValue is always <empty> for alias

[fflaten]

Checklist

• Issue has a meaningful title
• I have searched the existing issues. See all issues
• I have tested using the latest version of Pester. See Installation and update guide.

What is the issue?

Should -HaveParameter alias123 -DefaultValue ... can't be used with aliases (AliasInfo). Will always say default-value is empty because.

Expected Behavior

Should be able to check a parameters default value when referencing command by alias.

Steps To Reproduce

function Test-Parameter {
    param (
        [Parameter()]
        [string]
        $Name = 'test'
    )
}
New-Alias t Test-Parameter
Get-Command -Name t | Should -HaveParameter 'Name' -DefaultValue 'test'

Describe your environment

Pester version : 5.3.3 C:\Users\Frode\Documents\PowerShell\Modules\pester\5.3.3\Pester.psm1
PowerShell version : 7.3.1
OS version : Microsoft Windows NT 10.0.22621.0

Possible Solution?

Check if inputobject is of type AliasInfo and try to get the function/script using ResolvedCommand. If empty, write warning or fail, but at least we tried.

[fflaten]

Or should we just say aliases are unsupported? You really should know (and use) the real function name when writing tests.