Desperately need -ExcludeTags filter on Invoke-Pesteer

[fearthecowboy]

Howdy,

I'm writing the test suite for OneGet right now, and I reaaaaaaaly need a -ExcludeTags filter parameter on Invoke-Pester so I can run tests that aren't tagged with a particular tag.

@Jaykul said you guys were awesome and could do a quick implementation for a simple request like that really fast.

:)

[Jaykul]

Just to be clear, "Exclude" would win over "Tag" right? So, if we add this, and there is:

Describe "Files Must Have Names" "Named", "Special" {
   It "Has a Name" {
      $File = Get-Item ([IO.Path]::GetTempFileName())
      $File.Name | Should Not BeNullOrEmpty
  }
}

It wouldn't be run if we Invoke-Pester -Tag Named -Exclude Special

Right?

[fearthecowboy]

Yeah, sounds good to me.

[fearthecowboy]

Made a pull request for that.

#233

[dlwyatt]

Holy overnight emails, Batman! :)

Just to kick an idea around here, what do you think would be less confusing to the user? Having two separate parameters for Include / Exclude tags, or having a single parameter with negation semantics baked in? For example:

Invoke-Pester -Tags '*DoIt*', '!*DontDoIt*'

# versus

Invoke-Pester -Tags '*DoIt*' -ExcludeTags '*DontDoIt*'

In either case, we'd have to be clear on the behavior of the module when a user sends in multiple tags (negate takes precedence over allow, read from left to right, etc.) I'm just asking about the interface at this point, not the functionality.

[nohwnd]

@dlwyatt For me the (Include/)Exclude makes the most sense, because the Include Exclude syntax is familiar from Get-ChildItem -Include and -Exclude. Plus it is instantly visible in IntelliSense.

[Jaykul]

Yeah, I briefly considered putting negation into the tags filter itself, but backwards compatibility on the tags implementation is extremely fragile, and this would break it, because currently Pester does exact matching, so "!Fun" is a valid tag.

Note: although we don't allow spaces at invoke/test time, we do allow spaces in the actual tags -- even though they'll never match (this is a bug, but it can't be fixed without breaking changes!).

[Jaykul]

It might be useful to rename the "Tag" parameter to "IncludeTag" (with the "Tags" alias it already has, this wouldn't break anything) ...

[dlwyatt]

Sounds good, will review this tonight.