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Category: Testing

Using Pester To Validate Script Installations

Published 2016-09-29 by Kevin Feasel

Rob Sewell wants to use Pester to guarantee that he has Ola’s maintenance scripts installed on a server:

First I thought about what I would look for in SSMS when I had installed the maintenance solution and made a list of the things that I would check which looked something like this. This would be the checklist you would create (or have already created) for yourself or a junior following this install. This is how easy you can turn that checklist into a Pester Test and remove the human element and open your install for automated testing

  • SQL Server Agent is running – Otherwise the jobs won’t run🙂

  • We should have 4 backup jobs with a name of

  • DatabaseBackup – SYSTEM_DATABASES – FULL

  • DatabaseBackup – USER_DATABASES – FULL

  • DatabaseBackup – USER_DATABASES – DIFF

  • DatabaseBackup – USER_DATABASES – LOG

  • We should have Integrity Check and Index Optimisation Jobs

  • We should have the clean up jobs

  • All jobs should be scheduled

  • All jobs should be enabled

  • The jobs should have succeeded

There’s a very nice script and walkthrough of the process if you click through.

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Automating Data Warehouse Testing

Published 2016-09-26 by Kevin Feasel

Koos van Strien discusses warehouse testing:

Case: we’ve integrated two sources of customers. We want to add a third source.

Q: How do we at the same time know that our current integration and solutions will continue to work while at the same time integrating the new sources?

A: Test it.

Q: How do we get faster deployments and more stability?

A: Automate the tests, so they can run continuously.

This is an interesting concept; do read the whole thing.

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Understand Your Testing Utilities

Published 2016-09-13 by Kevin Feasel

David Klee shows an issue with using iperf for load testing:

The load test utility had maxed out the compute resource that it had available, due to internal limitations within iperf itself.  It’s a shame that this utility is not multi-threaded, because I think we could have a much greater result of improvement on this system.

Monitor the utilities that you’re using to do load testing, because limitations like this might skew your results!

Everything eventually hits a bottleneck.  In David’s case, the bottleneck was in the testing tool itself.

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tSQLt Visual Studio Test Adapter

Published 2016-08-19 by Kevin Feasel

Ed Elliott has a Visual Studio extension to run tSQLt tests:

What is this?

This lets you use Visual Studio to run tSQLt tests easily. Visual Studio has a built in framework for finding and executing tests so that if you have tSQLt tests in an SSDT project for example, although this just requires you have the .sql files in source control and does not require ssdt – you can easily see and execute your tests via the Visual Studio Test Explorer window. It is also available for use in your favorite build server via the vstest.console.exe tool or if you have vsts then you can use the default test task.

Combined with Visual Studio database tests for integration testing, this gives you a pretty fair start on database testing technology.

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Load Testing Analysis Services

Published 2016-08-16 by Kevin Feasel

Bill Anton provides Powershell code to load test Analysis Services cubes:

One of the more time consuming pieces in this process is step 4 – setting up a solution that can generate a concurrent query workload. Bob Duffy (b | t) has written blogs and delivered presentations on the topic of Analysis Services load testing. However, when it comes to tooling (unless something changed recently) I believe he’s still using a custom .NET Visual Studio Test solution for the test harness. And unless you know .NET, you’re going to have a pretty difficult time getting setup… which is why I was so happy when, earlier this year, Chris Schmidt (b | t) wrote a post over on MSDN demonstrating a method for load testing an Analysis Services database using PowerShell.

This weekend I finally had some time to expand upon Chris’ code sample and add several new features… e.g. parameters (target server/database, level of concurrency, queries per batch, etc) and the ability to retrieve MDX (or DAX) queries from a SQL table. In my experience, it’s quite a bit easier to generate a table of MDX/DAX queries rather than a bunch of txt files with a query in each file.

My first thought was “Well, that doesn’t seem too complicated.”  Which means that Bill did a great job.

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Unit Testing Of Spark Streaming

Published 2016-08-10 by Kevin Feasel

Felipe Fernandez shows how to unit test Spark Streaming:

Controlling the lifecycle of Spark can be cumbersome and tedious. Fortunately, Spark Testing Baseproject offers us Scala Traits that handle those low-level details for us. Streaming has an extra bit of complexity as we need to produce data for ingestion in a timely way. At the same time, Spark internal clock needs to tick in a controlled way if we want to test timed operations as sliding windows.

This is part one of a series.  I’m interesting in seeing where this goes.

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Credentials In Azure Automation

Published 2016-08-09 by Kevin Feasel

Mark Vaillancourt explains Azure automation credentials:

With that String parameters, it is easy to just type what I want in the textbox. But, for the PSCredential parameter at the bottom, I was unsure what to do. I figured, since this is just a textbox, I couldn’t just magically pass in a Credential Asset. So, I tried passing in an expression that used the Get-AzureRmAutomationCredential cmdlet that returns the Credential Asset specified. That didn’t work very well. I then started digging through documentation, figuring I would see references and examples of passing a Credential Asset in the Test Pane. It took me a bit, but I finally landed on an Azure.com blog post titled Azure Automation: Runbook Input, Output, and Nested Runbooks. While this post didn’t match all that closely with the search criteria around the Test Pane, it did contain my answer in a section on starting Runbooks:

The answer turns out to be pretty simple.

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Writing Good Tests In R

Published 2016-07-08 by Kevin Feasel

Brian Rowe discusses testing strategy in R:

It’s not uncommon for tests to be written at the get-go and then forgotten about. Remember that as code changes or incorrect behavior is found, new tests need to be written or existing tests need to be modified. Possibly worse than having no tests is having a bunch of tests spitting out false positives. This is because humans are prone to habituation and desensitization. It’s easy to become habituated to false positives to the point where we no longer pay attention to them.

Temporarily disabling tests may be acceptable in the short term. A more strategic solution is to optimize your test writing. The easier it is to create and modify tests, the more likely they will be correct and continue to provide value. For my testing, I generally write code to automate a lot of wiring to verify results programmatically.

I started this article with almost no idea how to test R code.  I still don’t…but this article does help.  I recommend reading it if you want to write production-quality R code.

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MSTest Output

Published 2016-06-16 by Kevin Feasel

Richie Lee shows how to use TestContext.WriteLine to debug MSTest runs:

Unit testing can sometimes throw up unexpected issues that are entirely concerned with the unit tests and not the application under test. Recently I’ve been having issues with DateTime formats affecting the results of the unit tests: the format of the DateTime was different on the build server than it was on my local machine. The stored procedure could not be altered (because reasons*). The datetime formats on both SQL and Windows were identical to my machine, and running the test itself on the build box caused the test to go green, so clearly there was something funky going on in the build process. SO I needed to find a way of logging the values during the process to verify where the issue was. And, as luck would have it, MSTest has such a method to help you. First create a private instance of the TestContext object in the TestClass, then you create a public property.

This turns out to be really easy to do.

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Pester For Configuration Checks

Published 2016-05-26 by Kevin Feasel

Rob Sewell talks about SQL Server configuration testing using Pester, a Powershell test framework:

Occasionally, for reasons I haven’t explored I had to test against the value property of the returned object

          It "The Full User Database Backup should be scheduled Weekly $OlaUserFullSchedule" {
$Return.OlaUserFullSchedule.value | Should Be $OlaUserFullSchedule
}

I wanted to be able to run the tests against environments or groups of servers with different default values so I parameterised the Test Results as well and then the logical step was to turn it into a function and then I could do some parameter splatting. This also gives me the opportunity to show all of the things that I am currently giving parameters to the test for

This is a nice walkthrough of Rob’s contribution, available on GitHub.

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