Testing Against a Remote Docker Host with AL Test Runner

Apologies for another post about AL Test Runner. If you don’t use or care about the extension you can probably stop reading now and come back next time. It isn’t my intention to keep banging on about it – but the latest version (v0.2.1) does plug a significant gap.

Next time I’ll move onto a different subject – some thoughts about how we use Git to manage our code effectively.

Developing Against a Remote Docker Container

While I still prefer developing against a local Docker container I know that many others publish their apps to a container hosted somewhere else. In which case your options for running tests against that container are:

  • Using the Remote Development capability of VS Code to open a terminal and execute PowerShell on the remote host – discussed here and favoured by Tobias Fenster (although his views on The Beautiful Game may make you suspicious of any of his opinions 😉)
  • Enabling PS-Remoting and opening a PowerShell session to the host to execute some commands over the network – today’s topic

Again, shout out to Max and colleagues for opening a pull request with their changes to enable this and for testing these latest mods.

Enable PS Remoting

Firstly, you’re going to need to be able to open a PowerShell session to the Docker host with:

New-PSSession <computer name>

I won’t pretend to understand the intricacies of setting this up in different scenarios – you should probably read the blog of someone who knows what they are talking about if you need help with it.

The solution will likely include:

  • Opening a PowerShell session on the host as administrator and running Enable-PSRemoting
  • Making sure the firewall is open to the port that you are connecting over
  • Passing a credential and possibly an authentication type to New-PSSession

To connect to my test server in Azure I run the following:

New-PSSession <server name> -Credential (Get-Credential) -Authentication Basic

AL Test Runner Config

They are several new keys in the AL Test Runner config file to accommodate remote containers. There are also a few new commands to help create the required config.

The Open Config File command will open the config JSON file or create it, if it doesn’t already exist. Set Container Credential and Set VM Credential can be used to set the credentials used to connect to the container and the remote host respectively.

The required config keys are:

Sample AL Test Runner config
  • dockerHost – the name of the server that is hosting the Docker containers. This name will be used to create the remote PowerShell session. Leaving this blank implies that containers are hosted locally and the extension will work as before
  • vmUserName / vmSecurePassword – the credentials used to connect to the Docker host
  • remoteContainerName – the name of the container to run tests against
  • newPSSessionOptions – switches and parameters that should be added to New-PSSession to open the session to the Docker host (see below)

The extension uses New-PSSession to open the PowerShell session to the Docker host. The ComputerName and Credential parameters will populated from the dockerHost and vmUserName / vmSecurePassword config values respectively.

Any additional parameters that must be specified should be added to the newPSSessionOptions config key. As in my case I run

New-PSSession <server name> -Credential <credential> -Authentication Basic

I need to set newPSSessionOptions in the config file to “-Authentication Basic”. You can use this key for -useSSL, -Port, -SessionOption or whatever else you need to open the session.

With the config complete you should be able to execute tests, output the results and decorate the test codeunits as if you were working locally. Beautiful.

As ever, feedback, suggestions and contributions welcome. Hosted on GitHub.

Remote Development with VS Code and AL Test Runner

The most obvious limitation of the AL Test Runner extension for VS Code has been that you need to run VS Code on the Docker host machine. That’s fine for us because we do all our development on local Docker containers but I’m aware that this isn’t everyone’s preferred process.

Local Repo and VS Code, Remote Docker Host

I guess if you’re not hosting the Docker container locally then you are hosting it on some remote server – maybe on your own hardware or maybe in Azure or another cloud. To get AL Test Runner working in this scenario you’d need the AL Test Runner PowerShell module imported on the host and PS Remoting enabled to execute PowerShell on the host from your local VS Code terminal.

This post isn’t about getting that working. It’s not supported yet – although I do have a pull request to review from a team that are using it like this (thanks Max).

Remote Development with VS Code

An alternative approach is to use remote development with VS Code. The files that you are working on and the Docker host are remote but you are using VS Code locally. Kind of like RemoteDesktop Apps – the benefit of running on a server and using its resources but with the experience of an app that is running locally.

Install Open SSH server on the remote machine, install some VS Code extensions (using an insider build of VS Code – for now) and connect over SSH to the machine. Some magic happens at the other end and a few spells, invocations and minutes later a VS Code Server is installed on the remote machine.

I won’t go into the setup. I mostly followed this excellent blog post from Tobias Fenster and used aka.ms/getbc to create a new VM in Azure to test with.

It allows you to work in a local VS Code window but access the file system of the server and execute commands on it. Install VS Code extensions and PowerShell modules as if you are working locally and they are installed on the remote.

It is smooth. Impressively so. You quickly forget that you aren’t just working with files and extensions on your local machine. This clip shows:

  • Selecting a folder on the remote server from my recent history
  • Connecting via SSH
  • Entering the password for the remote account that I am authenticating as (a local account as my VM in Azure is not joined to a domain)
  • Running all the tests in the project and working with VS Code as I would do locally
Connecting to remote host via SSH and running some tests

I still prefer actual local development, but I have to admit that this is pretty great.

AL Test Runner

I span up a remote development scenario out of curiosity but I also wanted to test how/if AL Test Runner would work. It works almost seamlessly. Almost. There is just a little stretch of exposing stitching – but it’s easy to work around.

Local and remote extensions in VS Code

Once you’ve opened a remote development window you’ll need to:

  • Install the AL extension
  • Install the AL Test Runner extension
  • Install the navcontainerhelper PowerShell module (you can use install-module in the integrated terminal)

If you try to run tests you’ll find that it appears to hang indefinitely. Actually it has popped a window to enter the credentials to connect to the server with – but you can’t see it and it won’t continue until you dismiss the window.

If you’re interested in trying it the workaround for now is to manually edit the config.json file in the .altestrunner folder.

When you first install the extension you won’t have a config.json file. Running a test, any test is enough to create it. You’ll also notice that the command appears to hang in the terminal. You can kill that terminal once the file has been created.

Open config.json and enter the userName to authenticate with BC. Next you need to enter the securePassword (this is not your plain text password). You can get the secure password running the following in the terminal:

ConvertTo-SecureString 'your password' -AsPlainText -Force | ConvertFrom-SecureString

Copy the huge string from the output into the securePassword key of the config file. After that you should be good to go.

At some point I’ll also work on the ability to use remote PowerShell to execute tests on a remote Docker host from your local machine. After all, Max has already done most of the work for me 🙂

AL Test Runner for Visual Studio Code

TL;DR

I’ve written an extension for VS Code to help run your AL tests in local Docker containers. Search for “AL Test Runner” in the extension marketplace or click here. Feedback, bugs, feature suggestions all gratefully received on the GitHub repo or james@jpearson.blog

Intro

As soon as Freddy added capability to the navcontainerhelper module to execute automated tests I was excited about the potential for:

  1. Making test execution in our build pipeline simpler and more reliable
  2. Running tests from Visual Studio Code as part while developing

I’ve written about both aspects in the past, but especially #1 recently – about incorporating automated tests into your Azure DevOps pipeline.

This post is about #2 – incorporating running tests as early as possible into your development cycle.

Finding Bugs ASAP

You’ve probably heard the idea – and it’s common sense even if you haven’t – that the cost of finding a bug in your software increases the later in the development/deployment cycle you find it.

If you realise you made a silly mistake in code that you wrote 2 minutes ago – there’s likely no harm done. Realise there is a bug in software that is now live in customers’ databases and the implications could be much greater. Potentially annoyed customers, data that now needs fixing, support cases, having to rush out a hotfix etc.

We’ve all been there. It’s not a nice place to visit. I once deleted all the (hundreds of thousands of) records in the Purch. Rcpt. Line table with a Rec.DELETEALL on a temporary table…turns out it wasn’t temporary…and I was working in the live database.

Writing automated tests can help catch problems before you release them out into the wild. They force you to think about the expected behaviour of the code and then test whether it actually behaves like that. Hopefully if the code that we push to a branch in Azure DevOps has a bug it will cause a test to fail, the artifacts won’t be published, the developer will get an email and the customer won’t be the hapless recipient of our mistake. No harm done.

However, the rising cost of finding a bug over time still applies. Especially if the developer has started working on something else or gone home. Getting back your head back into the code, reproducing and finding the bug and fixing it are harder if you’ve had a break from the code than if you went looking for it straight away.

Running Tests from VS Code

That’s why I’m keen that we run tests from VS Code as we are writing them. Write a test, see it fail, write the code, see the test pass, repeat.

I’ve written about this before. You can use tasks in VS Code to execute the required PowerShell to run the tests. The task gives you access to the current file and line no. so that you can fancy stuff like running only the current test or test codeunit.

AL Test Runner

However, I was keen to improve on this and so have started work on a VS Code extension – AL Test Runner.

Running the current test with AL Test Runner and navcontainerhelper

The goals are to:

  • Make it as simple as possible to run the current test, tests in the current codeunit or all tests in the extension with commands and keyboard shortcuts
  • Cache the test results
  • Decorate test methods according to the latest test results – pass, fail or untested
  • Provide extra details e.g. error message and callstack when hovering over the test name
  • Add a snippet to make it easier to create new tests with placeholders for GIVEN, WHEN and THEN statements

Important: this is for running tests with the navcontainerhelper PowerShell module against a local Docker container. Please make sure that you are using the latest version of navcontainerhelper.

Getting Started

  • Download the extension from the extension marketplace in VS Code and reload the window.
  • Open a folder containing an AL project
  • Open a test codeunit, you should notice that the names of test methods are decorated with an amber background (as there are no results available for those tests)
    • The colours for passing, failing and untested tests are configurable if you don’t like them or they don’t fit with your VS Code theme. Alternatively you can turn test decoration off altogether if you don’t like it
  • Place the cursor in a test method and run the “AL Test Runner: Run Current Test” command (Ctrl+Alt+T)
  • You should be prompted to select a debug configuration (from launch.json), company name, test suite name and credentials as appropriate (depends if you’re running BC14 or BC15, if you have multiple companies, authentication type etc.)
    • I’ve noticed that sometimes the output isn’t displayed in the new terminal when it is first created – I don’t know why. Subsequent commands always seem to show up fine 🤷‍♂️
  • Use the “ttestprocedure” to create new test methods

.gitignore

If you’re using Git then I’d recommend adding the .altestrunner folder to your .gitignore file:

.altestrunner/

Committing the config file and the test results xml files doesn’t feel like a great idea.

You Can Ditch Our Build Helper for Dynamics 365 Business Central

I’m a bit of a minimalist when it comes to tooling, so I’m always happy to ditch a tool because its functionality can be provided by something else I’m already using.

In a previous post I described how we use our Build Helper AL app to prep a test suite with the test codeunits and methods that you want to run. Either as part of a CI/CD pipeline or to run from VS Code.

Freddy K has updated the navcontainerhelper PowerShell module and improved the testing capabilities – see this post for full details.

The new extensionId parameter for the Run-TestsInBCContainer function removes the need to prepare the test suite before running the tests. Happily, that means we can dispense with downloading, publishing, installing, synchronising and calling the Build Helper app.

The next version of our own PowerShell module will read the app id from app.json and use the extensionId parameter to run the tests. Shout out to Freddy for making it easier than ever to run the tests from the shell 👍

Stop Writing Automated Tests and Get On With Some Real Code

To be fair, these weren’t the exact words that were used, but a view was expressed from the keynote stage at Directions last week along these lines. Frustration that developers now have to concern themselves with infrastructure, like Docker, and writing automated tests rather than “real” code.

I couldn’t resist a short post in response to this view.

If It Doesn’t Add Value, Stop Doing It!

First, no one is forcing you to write automated tests – apart from Microsoft, who want them with your AppSource app submission. Even then, I haven’t heard of Microsoft rejecting an app because it wasn’t accompanied by enough automated tests.

I’m an advocate of developers taking responsibility for their own practices. Don’t follow a best practice simply because someone else tells you it’s a best practice. You know your scenario, your team, your code and your customers better than anyone else. You are best placed to judge whether implementing a new practice is worth the cost of getting started with it.

AppSource aside, if you are complaining about the amount of time you have to spend on writing tests then you have no one to blame but yourself. Or maybe your boss. If you don’t see the value in writing automated tests then you probably should stop wasting your time writing them!

Automated Tests vs “Real” Code

Part of the frustration with tests seemed to be that they aren’t even “real” code. If by “real” code we are referring to the code that we deliver and sell to customers then no, tests aren’t real code.

But what are we trying to achieve? Surely working, maintainable code that adds value for our customers.

We might invest in lots of things in pursuit of that goal. Time spent manually testing, sufficient hardware to develop and test the code on, an internet connection to communicate with each other and the customer, office space to work in, training courses and materials, coffee. We’re not selling these things to the customer either but no one would question that they are necessary to achieve the goal of delivering working software. Especially the coffee.

Whether or not automated tests are “real” code is the wrong question. The important judgement is whether the time spent on writing them makes a big enough contribution to the quality of the product that you eventually ship.

I won’t make the case for automated testing here. That’s for a different post. Or a different book. Suffice to say, I do think it is worth the investment.

But We’ve Got a Backlog of Code Not Covered By Tests

One problem you might have is that you’ve got a backlog of legacy code that isn’t covered by any automated tests. Trying to write tests to cover it all will take ages. This frustration also seemed to be expressed by the speaker at Directions. It even got a round of applause from some of the Directions audience.

My response would be the same – you are best placed to make a pragmatic judgement. Of course it would be nice to have 100% code coverage of your tens of thousands of lines of legacy code – but if you’ll have to stop developing new features for six months to achieve it, is it worth it? Probably not.

Automated tests should give you confidence that the code works as expected. If you are already confident that your existing code works then there might be limited value in writing a suite of tests to prove it.

Try starting with tests to cover new features that you develop or bug fixes. With these cases you’ve got some code that you aren’t confident works as expected – or that you know doesn’t. Take the opportunity to document and prove the expected behaviour with some tests. Over time you’ll build a valuable suite of tests that you can run to demonstrate that each new release of your product works and that bugs haven’t been reintroduced.

With some practice you’ll find that you can use the library codeunits to create scenarios with little test code e.g. you can create a customer, item and sales order, post it and get the posted sales invoice in 2 lines of code.

Interested? More here