FixedFunction.ps1

function New-PSRepositoryRequirement {
    param (
        [string]$Name,
        [string]$Uri,
        [string]$Policy = 'Trusted'
    )
    New-RequirementGroup 'Repository' -ScriptBlock {
        @{
            Describe = "$Name is registered"
            Test     = {
                $repo = Get-PSRepository -Name $Name
                $repo.SourceLocation -eq $Uri
            }
            Set      = {
                Register-PSRepository -Name $Name `
                    -SourceLocation $Uri `
                    -PublishLocation $Uri `
                    -InstallationPolicy $Policy
            }
        }
    }.GetNewClosure()
}

Requirements.ps1

function New-PSRepositoryRequirement {
    param (
        [string]$Name,
        [string]$Uri,
        [string]$Policy = 'Trusted'
    )
    New-RequirementGroup 'Repository' -ScriptBlock {
        @{
            Describe = "$Name is registered"
            Test     = {
                $repo = Get-PSRepository -Name $Name
                $repo.SourceLocation -eq $Uri
            }
            Set      = {
                Register-PSRepository -Name $Name `
                    -SourceLocation $Uri `
                    -PublishLocation $Uri `
                    -InstallationPolicy $Policy
            }
        }
    }
}


& {New-PSRepositoryRequirement -Name artifactory -Uri https://url/artifactory/api/nuget/powershell}`
| Invoke-Requirement