Tag Archives: Visual Studio

Live Testing in Visual Studio 2017

While working on this project, I decided that I would see how useful the new feature of “Live Testing” is for TDD.

Once you’ve created your suite of tests, turning live testing on gives you some interesting information:

As you can see, there are some slight contradictions here in what it’s telling me. The first test is failing, the test for Count has a line (which indicates not covered). However, code lens is telling me there are two covering tests.

My suspicion here is that live testing is being too clever for its own good; for example, looking at the tests themselves, shows that only the first Enqueue statement is covered:

My thoughts are that the engine works out where the test fails, and so, in the case above, it’s telling me that the tests are not running the line of code that tests the Count functionality. What I’m guessing is that this is because the tests are failing before that.

I can prove this by creating a further unit test:

And, indeed, this now shows coverage:

As I start to add the functionality, I can quickly see that the tests are now passing:

Changing the way code is written

The interesting thing here is that is promotes two things:
1. Defined tests – if a test covers more than one thing, it will show as uncovered initially
2. Tests first – obviously, there need to be tests to show test coverage

Caveats

1. Annoyingly, by default, you continually have to opt in for live unit testing. It only starts when you select to “Start” live unit testing, and this must be done each time you launch VS. This is configurable, and can be switched on by default in options:

2. If the build fails, it shows nothing.

3. Live testing is only available in Visual Studio Enterprise.

NUnit

One thing that only occurred to me as notable while I was writing this is that the tests that I’ve written are in NUnit. So the Live Testing clearly works with none MSTests, and probably works with anything that’ll show up in Test Explorer / Code Lens.

References

https://blogs.msdn.microsoft.com/visualstudio/2017/03/09/live-unit-testing-in-visual-studio-2017-enterprise/

Convert a standard C# project into a Unit Test project

I recently (accidentally) created a Unit Test project as a standard C# class library. Although you don’t need to change this to a test library (it basically just gives you the test icon instead of the class icon), I felt that, if I wanted to do this, it shouldn’t require that I delete and recreate the project.

To change the project type

If you open the csproj for a class library, it looks like this (or some of it does):

<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
  <PropertyGroup>
    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
    <ProjectGuid>{93F28F24-AD9B-4839-8697-6DA48BAB2048}</ProjectGuid>
    <OutputType>Library</OutputType>
    <AppDesignerFolder>Properties</AppDesignerFolder>
    <RootNamespace>MyProject.UnitTests</RootNamespace>
    <AssemblyName>MyProject.UnitTests</AssemblyName>
    <TargetFrameworkVersion>v4.5.2</TargetFrameworkVersion>
    <FileAlignment>512</FileAlignment>

All you need to do is add the correct ProjectTypeGuids:

<ProjectTypeGuids>{3AC096D0-A1C2-E12C-1390-A8335801FDAB};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>

References

https://www.codeproject.com/Reference/720512/List-of-Visual-Studio-Project-Type-GUIDs

http://stackoverflow.com/questions/2911565/what-is-the-significance-of-projecttypeguids-tag-in-the-visual-studio-project-fi

Start Two Project Simultaneously

In Investigating message queues with RabbitMQ and ActiveMQ, I came across a problem that I’ve never considered before. Starting two projects at the same time.

The well-known (at least to me) way of doing this was to start the start-up project, and then right-click the second project, and select Start New Instance:

2proj

However, this is laborious when you’re constantly starting both projects. So, the alternative is to right click the solution, and select Set StartUp Projects… :

2proj2

Then you can select to start multiple projects:

2proj3

A small thing, but saves a lot of time.

The “GenerateResource” task failed unexpectedly

I recently started getting this error on a solution:

GenerateResource

It didn’t actually report any errors, other than this and, no matter what I tried (deleting the suo file, rebuilding, cleaning, etc.), it wouldn’t go away.

Finally, I ran up a command prompt and tried to compile it there. I immediately got this error:

MyViewModel.cs(63,28): error CS1056: Unexpected character ‘$’ [C:\Users\Paul\Desktop\MyApp\MyApp\kqlonrzo.tmp_proj]

Okay, so, the project definitely did use the new $ character. Here’s the thing, whilst I was trying to compile using VS2015, the version of the command prompt that I had run was 2012. The next thing was to try running the command prompt for VS2015.

This gave a less than useful error regarding `MyProject.csproj.metadata` file. So, next I tried compiling the project directly from the command line.

Finally, that worked. Unfortunately, I was unable to break the compile again. However, it isn’t the first time that I’ve encountered this error: hence this post.

So, whilst not proven, for next time, try compiling the solution using the command line and, if that doesn’t work, try compiling the individual project file first.

Now using Visual Studio 14 CTP

I was previously using VS2013, but after running 14 just once, I saw no reason to go back. I thought I’d jot down some notes on my experience of this update. A quick caveat though: VS14 is a CTP, so if you’re thinking about using it to maintain the code for your nuclear reactor, then probably don’t.

Faster

Okay, so this is my perception. I’m working on a personal project on the train to and from work. VS14 loads almost a station before VS2013 did. Now, if that’s not a fair and accurate benchmark, I don’t know what is!

Debugging

One particularly cool feature is that you can see the CPU execution time for previous statement during debugging. Typically, this is a meaninglessly low figure of x milliseconds; but occasionally it shows an unexpectedly high figure.

This can be dangerous, because if you saw a statement that took 30ms, which executed once when the user presses a button in your app, you might think nothing of it… unless all the other statements take 2ms. At this point, you might spend 1/2 hour trying to work out what the bottleneck is. You might even find it: and speed up your app by 28ms.

Refactor

Shift-Alt-F10 on a non-existent method now gives you a preview of what it’s about to do. Possibly not the most useful feature in the world to be honest, but if you want a field and it tries to create a property then you know (obviously, if you’d just read the description of what it will create, that would also tell you). The Using statement tells you where it will create the statement:

preview

However, I can’t find any way you can affect the preview – which would have been a nice feature; for example, say you wanted to create a public field rather than internal; or, you wanted to define a constant and give it a constant value.

Light bulbs now appear next to potential refactoring. One example was an unnecessary using statement I had. It had turned grey; I didn’t understand this until I noticed that a light bulb had appeared next to it, which helpfully informed me that I didn’t need the statement.

Also, code analysis seems to be an opt-in thing now – rather than the previous version which seemed to constantly kidnap whichever tab it was on.

It is still a CTP

Line numbers were turned on in VS2013 and were off in 14.