Pester for Presentations – Ensuring it goes ok

Whilst I was at PSCONFEU I presented a session on writing pester tests instead of using checklists. You can see it here

During the talk I showed the pester test that I use to make sure that everything is ready for my presentation. A couple of people have asked me about this and wanted to know more so I thought that I would blog about it.

Some have said that I might be being a little OCD about it 😉 I agree that it could seem like that but there is nothing worse than having things go wrong during your presentation. It makes your heart beat faster and removes the emphasis from the presentation that you give.

When it is things that you as a presenter could have been able to foresee, like a VM not being started or a database not being restored to the pre-demo state or being logged in as the wrong user then it is much worse

I use Pester to ensure that my environment for my presentation is as I expect and in fact, in Hanover when I ran through my Pester test for my NUC environment I found that one of my SQL Servers had decided to be in a different time zone and therefore the SQL Service would not authenticate and start. I was able to quickly remove the references to that server and save myself from a sea of red during my demos

For those that don’t know. Pester is a PowerShell module for Test Driven Development

Pester provides a framework for running unit tests to execute and validate PowerShell commands from within PowerShell. Pester consists of a simple set of functions that expose a testing domain-specific language (DSL) for isolating, running, evaluating and reporting the results of PowerShell commands

If you have PowerShell version 5 then you will have Pester already installed although you should update it to the latest version. If not you can get Pester from the PowerShell Gallery follow the instructions on that page to install it. This is a good post to start learning about Pester

What can you test? Everything. Well, specifically everything that you can write a PowerShell command to check. So when I am setting up for my presentation I check the following things. I add new things to my tests as I think of them or as I observe things that may break my presentations. Most recently that was ensuring that my Visual Studio Code session was running under the correct user. I did that like this

Describe "Presentation Test" {
    Context "VSCode" {
        It "Should be using the right username" {
            whoami | Should Be 'TheBeard\Rob'
       }
    }
}

01 - username.PNG

I think about the things that are important to me for my presentation.  I want to ensure that I only have one VS Code window open to avoid that situation where I am clicking through windows looking for the correct window. I can do that using Get-Process

It "Should have Code Insiders Open" {
(Get-Process 'Code - Insiders' -ErrorAction SilentlyContinue)| Should Not BeNullOrEmpty
}
        It "Should have One VS Code Process" {
            (Get-Process 'Code - Insiders' -ErrorAction SilentlyContinue).Count | Should Be 1
        }

I use -ErrorAction SilentlyContinue so that I don’t get a sea of red when I run the tests. Next I want to check my PowerPoint is ready for my presentation

[code langauge=”PowerShell”]
It "Should have PowerPoint Open" {
(Get-Process POWERPNT -ErrorAction SilentlyContinue).Count | Should Not BeNullOrEmpty
}
It "Should have One PowerPoint Open" {
(Get-Process POWERPNT -ErrorAction SilentlyContinue).Count | Should Be 1
}
It "Should have the correct PowerPoint Presentation Open" {
(Get-Process POWERPNT -ErrorAction SilentlyContinue).MainWindowTitle| Should Be ‘dbatools – SQL Server and PowerShell together – PowerPoint’
}

Again I use Get-Process. I check if PowerPoint is open, if there is one PowerPoint open and I use the MainWindowTitle property to check that it is the right PowerPoint presentation after nearly starting a presentation for SqlServer module with the dbatools slides!

I don’t want any distractions when I am presenting. I have the sort of friends who will notice if I get notifications for twitter popping up on my screen and repeatedly send tweets to make people laugh. (I admit, I’m one of those friends – I do this too!)

02 - Friends!!.PNG

Now I cannot get a test for quiet hours working. You can apparently use a Registry key, which of course you can check with PowerShell but I was unable to get it working. I haven’t looked at testing for Presentation Mode  but I test that those programmes are shut down, again using Get-Process

        It "Mail Should be closed" {
            (Get-Process HxMail -ErrorAction SilentlyContinue).Count | Should Be 0
        }
        It "Tweetium should be closed" {
            (Get-Process WWAHost -ErrorAction SilentlyContinue).Count | Should Be 0
        }
        It "Slack should be closed" {
            (Get-Process slack* -ErrorAction SilentlyContinue).Count | Should BE 0
        }

I am generally presenting with SQL Server so I need to make sure that SQL Server is running. I do this with Get-Service

Context "Local SQL" {
        It "DBEngine is running" {
            (Get-Service mssqlserver).Status | Should Be Running
        }
        It "SQL Server Agent is running" {
            (Get-Service sqlserveragent).Status | Should Be Running
        }
        It "DAVE DBEngine is running" {
            (Get-Service mssql*Dave).Status | Should Be Running
        }
        It "DAVE Agent is running" {
            (Get-Service sqlagent*dave).Status | Should Be Running
        }
    }

In this example I am testing that the SQL Service and the Agent service are running on both of my local instances.

I use a NUC running Hyper-V to enable me to show a number of SQL Servers running in a domain environment so I need to be able to test those too. I set the values of the servers I need into a variable and check that the VM is running and that they respond to ping

 Context "VM State" {
        $NUCServers = 'BeardDC1','BeardDC2','LinuxvNextCTP14','SQL2005Ser2003','SQL2012Ser08AG3','SQL2012Ser08AG1','SQL2012Ser08AG2','SQL2014Ser12R2','SQL2016N1','SQL2016N2','SQL2016N3','SQLVnextN1','SQL2008Ser12R2'
        $NUCVMs = Get-VM -ComputerName beardnuc | Where-Object {$_.Name -in $NUCServers}
            foreach($VM in $NUCVms)
                {
                $VMName = $VM.Name
                  It "$VMName Should be Running"{
                    $VM.State | Should Be 'Running'
                  }
			    }
    }
Context "THEBEARD_Domain" {
            $NUCServers = 'BeardDC1','BeardDC2','LinuxvNextCTP14','SQL2005Ser2003','SQL2012Ser08AG3','SQL2012Ser08AG1','SQL2012Ser08AG2','SQL2014Ser12R2','SQL2016N1','SQL2016N2','SQL2016N3','SQLVnextN1','SQL2008Ser12R2'
            foreach($VM in $NUCServers)
                {
                                 It "$VM Should respond to ping" {
				(Test-Connection -ComputerName $VM -Count 1 -Quiet -ErrorAction SilentlyContinue) | Should be $True
				}
                }
    }

I also need to check if the SQL Service and the Agent Service is running on each server

  Context "SQL State" {
        $SQLServers = (Get-VM -ComputerName beardnuc | Where-Object {$_.Name -like '*SQL*'  -and $_.State -eq 'Running'}).Name
        foreach($Server in $SQLServers)
        {
          $DBEngine = Get-service -ComputerName $Server -Name MSSQLSERVER
           It "$Server  DBEngine should be running" {
                $DBEngine.Status | Should Be 'Running'
            }
           It "$Server DBEngine Should be Auto Start" {
            $DBEngine.StartType | Should be 'Automatic'
           }
              $Agent= Get-service -ComputerName $Server -Name SQLSERVERAGENT
              It "$Server Agent should be running" {
                  $Agent.Status | Should Be 'Running'
           }
           It "$Server Agent Should be Auto Start" {
            $Agent.StartType | Should be 'Automatic'
           }
        }
        It "Linux SQL Server should be accepting connections" {
            $cred = Import-Clixml C:\temp\sa.xml
            {Connect-DbaSqlServer -SqlServer LinuxvnextCTP14 -Credential $cred -ConnectTimeout 60} | Should Not Throw
        }

    }
}

I check that the Linux SQL Server is available by storing the credential using Export-CliXML  and then use that credential with Connect-DbaSqlServer from dbatools

Using a NUC means I sometimes have fun with networking so I have a couple of tests for that too. Testing for the correct DNS Servers and gateways

    It "Should have DNS Servers for correct interface" {
        (Get-DnsClientServerAddress -InterfaceAlias 'Ethernet 3').Serveraddresses | Should Be @('10.0.0.1','10.0.0.2')
    }
    It "Should have correct gateway for alias"{
        (Get-NetIPConfiguration -InterfaceAlias 'Ethernet 3').Ipv4DefaultGateway.NextHop | Should Be '10.0.0.10'
    }

All of those are generic tests that have evolved over time and are run for every presentation but when I have specific things you require for a single presentation I test for those too.

For Example, later this week Cláudio Silva and I are presenting on dbatools at TUGAIT  We are showing the Test-DbaMaxMemory  , Get-DbaMaxMemory and Set-DbaMaxMemory commands so we need to ensure that the Max Memory for some servers is (In) Correctly set. I use Connect-DbaSqlServer to create an SMO Server object and test that

    It "Max Memory on SQl2012SerAG1 2 and 3 should be 2147483647" {
        (Connect-DbaSqlServer SQL2012Ser08AG1).Configuration.MaxServerMemory.RunValue | Should Be 2147483647
        (Connect-DbaSqlServer SQL2012Ser08AG2).Configuration.MaxServerMemory.RunValue | Should Be 2147483647
        (Connect-DbaSqlServer SQL2012Ser08AG3).Configuration.MaxServerMemory.RunValue | Should Be 2147483647
    }

We are also showing the Test-DbaIdentityUsage command so a column needs to be pre-prepared in AdventureWorks2014 to be able to show the error

    It "ShiftID LastValue Should be 255" {
        $a = Test-DbaIdentityUsage -SqlInstance ROB-XPS -Databases AdventureWorks2014 -NoSystemDb
        $a.Where{$_.Column -eq 'ShiftID'}.LastValue | should Be 255
    }

To ensure that we have orphaned files available for the Find-DbaOrphanedFile command I use this

    It "has Orphaned Files ready"{
        (Find-DbaOrphanedFile -SqlServer SQL2016N2).Count | Should Be 30
    }

There are any number of things that you may want to test to ensure that, as best as possible, the demo gods are not going to come and bite you in the middle of your presentation.

  • Files or Folders exist (or dont exist)
  • Databases, Agent Jobs, Alerts
  • Operators, Logins
  • SSIS packages, SSRS Reports
  • PowerBi files
  • Azure connectivity
  • Azure components

The list is endless, just look at what you require for your presentation.

Anything you can check with PowerShell you can test with Pester so build up your Pester presentation tests and reduce the reliance on the demo gods! I’ll still leave this here just to be safe!!

pray to the demo gods.jpg

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Pester Test Inception and the Show Parameter

My fantastic friend Andre Kamman b | t  and I presented at PSConfEu last week

C_EDtK0XoAA1PL7 (2).jpg

and whilst we were there we were chatting about running Pester Tests. He wanted to know how he could run a Pester Test and not lose the failed tests as they scrolled past him. In his particular example we were talking about running hundreds of tests on thousands of databases on hundreds of servers

01 - pesters.gif

I guess it looks something like that!!

I explained about the -Show parameter which allows you to filter the results that you see. Using Get-Help Invoke-Pester you can see this

   -Show
Customizes the output Pester writes to the screen. Available options are None, Default,
Passed, Failed, Pending, Skipped, Inconclusive, Describe, Context, Summary, Header, All, Fails.

The options can be combined to define presets.
Common use cases are:

None – to write no output to the screen.
All – to write all available information (this is default option).
Fails – to write everything except Passed (but including Describes etc.).

A common setting is also Failed, Summary, to write only failed tests and test summary.

This parameter does not affect the PassThru custom object or the XML output that
is written when you use the Output parameters.

Required?                    false
Position?                    named
Default value                All
Accept pipeline input?       false
Accept wildcard characters?  false

So there are numerous options available to you. Lets see what they look like

I will use a dummy test which creates 10 Context blocks and runs from 1 to 10 and checks if the number has a remainder when divided by 7

Describe "Only the 7s Shall Pass" {
    $Servers = 0..10
    foreach($Server in $servers)
    {
        Context "This is the context for $Server" {
        foreach($A in 1..10){
            It "Should Not Pass for the 7s" {
                $A % 7 | Should Not Be 0
                }
            }
        }
    }
}

Imagine it is 10 servers running 10 different tests

For the Show parameter All is the default, which is the output that you are used to

02 - All.gif

None does not write anything out. You could use this with -Passthru which will pass ALL of the test results to a variable and if you added -OutputFile and -OutputFormat then you can save ALL of the results to a file for consumption by another system. The -Show parameter only affects the output from the Invoke-Pester command to the host not the output to the files or the variable.

Header only returns the header from the test results and looks like this ( I have included the none so that you can see!)

03 - none and header.PNG

Summary, as expected returns only the summary of the results

04 - summary.PNG

You can use more than one value for the Show parameter so if you chose Header, Summary, Describe you would get this

05 - headerdesscribe sumnmary.PNG

You could use Failed to only show the failed tests which looks like this

06 - failed.PNG

but Andre explained that he also want to be able to see some progress whilst the test was running. If there were no failures then he would not se anything at all.

So Fails might be the answer (or Failed and Summary but that would not show the progress)

07 - fails.PNG

Fails shows the Header, Describe, Context  and also shows the Summary.

However we carried on talking. PSConfEU is a fantastic place to talk about PowerShell 🙂 and wondered what would happen if you invoked Pester from inside a Pester test. I was pretty sure that it would work as Pester is just PowerShell but I thought it would be fun to have a look and see how we could solve that requirement

So I created 3 “Internal Tests” these are the ones we don’t want to see the output for. I then wrote an overarching Pester test to call them. In that Pester test script I assigned the results of each test to a variable which. When you examine it you see

08 - Pester Object.PNG

The custom object that is created shows the counts of all different results of the tests, the time it took and also the test result.

So I could create a Pester Test to check the Failed Count property of that Test result

$InternalTest1.FailedCount | Should Be 0

To make sure that we don’t lose the results of the tests we can output  them to a file like this

$InternalTest1 = Invoke-Pester .\Inside1.Tests.ps1 -Show None -PassThru -OutputFile C:\temp\Internal_Test1_Results.xml -OutputFormat NUnitXml

So now we can run Invoke-Pester and point it at that file and it will show the progress and the final result on the screen.

09 finale.PNG

You could make use of this in different ways

  • Server 1
    • Database1
    • Database2
    • Database3
    • Database4
  • Server 2
    • Database1
      Database2
      Database3
      Database4
  • Server 3
    • Database1
      Database2
      Database3
      Database4

Or by Test Category

  • Backup
    • Server1
    • Server 2
    • Server 3
    • Server 4
  • Agent Jobs
    • Server 1
    • Server 2
    • Server 3
    • Server 4
  • Indexes
    • Server 1
    • Server 2
    • Server 3
    • Server 4

Your only limitation is your imagination.

As we have mentioned PSConfEU you really should check out the videos on the youtube channel All of the videos that were successfully recorded will be on there. You could start with this one and mark your diaries for April 16-20 2018