Output gets butchered if Invoke-Pester is called with 6>&1

[abbbi]

If stream 6 is redirected via 6>&1 the output includes additional newlines and looks like:

       [?] test1
     , is inconclusive, because Skip test on linux
     11ms
     Describing testcaess
      [+] test2
      73ms
       [+] test3
     351ms

[fflaten]

Still reproduceable in Pester v5, but not sure how to address this issue.

Pester currently relies heavily on Write-Host to show progress without filling the output stream with noise. As of Powershell 5.0, Write-Host is just a wrapper around Write-Information which uses stream 6. When you redirect the stream, it loses the formatting when captured (redirected) and you get every message provided to Write-Host on it's own line, something that will happen often since we use multiple calls per line to modify colors.

Demo:

& { Write-Host "Demo" -NoNewline; Write-Host "Time" -NoNewline }
DemoTime

& { Write-Host "Demo" -NoNewline; Write-Host "Time" -NoNewline } 6>&1
Demo
Time

The only solutions I can think of is:

• Use ANSI escaped sequences to output colors/style so we could use a single call to Write-Host per line. Then you'd only lose the formatting on stream-redirect while keeping the original lines/structure. However, ANSI-support is lacking pre-Win10. Would require us to check on $host.UI.SupportsVirtualTerminal -eq $true and provide two output-plugins. I know ANSI has been mentioned in RFC: Better API for Invoke-Pester #1265 too.
• Replace Write-Host with [Console]::WriteLine/Write. Would be faster, but you'd lose the ability to redirect the output inside of powershell (would have to call invoke-pester in a sub-process).

[nohwnd]

@abbbi Why do you need that redirect? Maybe you can work around that in a different way.

@fflaten Both your suggestions are valid, but as you pointed out are also not without their downsides. Unless there is a really good reason for that redirect I'd say we should close this as won't fix.

[fflaten]

Correction about my ANSI-suggestion. Even redirected, you'd keep the formatting. I'd suggest implementing it at some point to support colors in CI/CD logs too as mentioned in the related issue.

We could then keep this issue in mind to use one call to write-host per line in that.

[nohwnd]

Moved that comment to #1953

[abbbi]

@abbbi Why do you need that redirect? Maybe you can work around that in a different way.

its not a requirement. I was executing pester via vagrant provisioning scripts, and noticed that the output format is quite broken then.

[nohwnd]

In that case we won't fix that because it would just replace this issue with another. Sorry.