Should exist behaving oddly?

[pcgeek86]

I have the following Pester test, which is failing. Anyone know how to rewrite this test so that it succeeds? How do I properly use the Should Exist command?

Describe DNS {
  it 'Google DNS should be accessible' {
    (Resolve-DnsName -Server 8.8.8.8 -Name trevorsullivan.net) | Should Exist
  }
}

Actual Result

 [-] Google DNS should be accessible 113ms
   Expected: {Microsoft.DnsClient.Commands.DnsRecord_A} to exist
   4:     (Resolve-DnsName -Server 8.8.8.8 -Name trevorsullivan.net) | Should Exist
   at <ScriptBlock>, <No file>: line 4

Expected Result

Test passes.

[fflaten]

Should -Exists is for testing paths, ex. a filesystem path. See https://pester.dev/docs/assertions/#exist

In your example, you'd probably want to use Should -Not -BeNullOrEmpty, or save the response in a variable and test one or more properties (count, IP, record types etc.) using Should -Be, Should -HaveCount etc.

[pcgeek86]

Thanks, I also tried Should Not Throw and that seemed to work okay.

[fflaten]

Also an option, but remember:

• Resolve-DnsName doesn't throw a terminating error (required for -Throw to work) by default. Use -ErrorAction Stop.
• Should -Throw expects a scriptblock unlike the other assertions

Ex: { Resolve-DnsName -Server 8.8.8.8 -Name trevorsullivan.net -ErrorAction Stop } | Should -Not -Throw.