Best/cleaner way to run same test against multiple instances.

[OranguTech]

Hello again, I have a test like this:

    It 'Checks DB Compatibility Level is 2025' {
        $DB = Get-DbaDatabase $DBConnection -Database @('ACMECustomers', 'ACMEProducts';) | Get-DbaDbCompatibility
        $DB.Compatibility | Should -Be 'Version170'
     
    }

This works fine against a single instance, but if I run that against multiple endpoints, the result is an array, and then the test fails.

Is there a more "pester native" way to say "Run this test against every instance I hand you" other than foreach?

        #Multi Version 
        $DB | % { $_.Compatibility | Should -Be 'Version170'  }

But that's
1 - A bit less clear, and semantically just feels "ugly".
2 - If one instance fails, it's not clear which instance, just that at least one did.

(This is currently using Pester v5)

[fflaten]

I'd recommend using data-driven tests. It would scale your tests to match the number of instance*databases and identity each combination in the test name/path. E.g.

Describe "SQL Checks" {
    BeforeDiscovery {
        $DBConnections = ... # Define/get one or more instance names
    }

    Context 'Instance <_>' -ForEach $DBConnections {
        BeforeDiscovery {
            $currentConn = $_ # not required, just to simplify explanation
            $Databases = Get-DbaDatabase $currentConn -Database @('ACMECustomers', 'ACMEProducts')
        }

        Context 'Database <_.Name>' -ForEach $Databases {
            BeforeAll {
                $currentDb = $_ # not required, just to simplify explanation
            }
            It 'Is compatible with Version170' {
                $compat = $currentDb | Get-DbaDbCompatibility
                $compat.Compatibility | Should-Be 'Version170'
            }
        }
    }
}

---

Side-note: In Pester v6 you could replace $DB | % { $_.Compatibility | Should -Be 'Version170' } in your original post with $DB | Should-All { $_.Compatibility | Should-Be 'Version170' }, but it wouldn't help you identify the database.