How to set the culture in a dotnetcore xunit test

Question

I have the following unit test that I'm porting from a .Net Framework library to .Net core xunint test library. The project the unit test needs to be added to is

https://github.com/dotliquid/dotliquid

and is being added to the selected file as show here

The unit test I'm trying to add is

[Test]
public void ParsingWithCommaDecimalSeparatorShouldWork()
{
    var ci = new CultureInfo(CultureInfo.CurrentCulture.Name)
             {
                 NumberFormat =
                 {
                     NumberDecimalSeparator = ","
                     , NumberGroupSeparator = "."
                 }
             };
    Thread.CurrentThread.CurrentCulture = ci;

    var t = Template.Parse("{{2.5}}");
    var result = t.Render( new Hash(), CultureInfo.InvariantCulture );
    Assert.AreEqual( result, "2.5"   );
}

However the test fails to compile in dotnet core.

Severity Code Description Project File Line Suppression State Error CS1061 'Thread' does not contain a definition for 'CurrentCulture' and no extension method 'CurrentCulture' accepting a first argument of type 'Thread' could be found (are you missing a using directive or an assembly reference?) DotLiquid.Tests(net451) C:\Users\phelan\workspace\dotliquid\src\DotLiquid.Tests\OutputTests.cs 113 N/A

I need to have different unit tests with different cultures. I would like to create an XUnit theory where each instance passes in a different culture for the unit test to verify against. How is this done in .NetCore?

Aaron Roberts · Accepted Answer · 2017-09-13T15:41:55.737

11

I looked at some of the dotnet source and I found this.

CultureInfo.DefaultThreadCurrentCulture = ci;

Basically it looks like you can set the default thread current culture from a static property of CultureInfo rather than from Thread.CurrentThread

poking around a bit more I found this

public CultureInfo CurrentCulture
{
    get
    {
        Contract.Ensures(Contract.Result<CultureInfo>() != null);
        return CultureInfo.CurrentCulture;
    }

    set
    {
        Contract.EndContractBlock();

        // If you add more pre-conditions to this method, check to see if you also need to 
        // add them to CultureInfo.DefaultThreadCurrentCulture.set.

        if (m_CurrentCulture == null && m_CurrentUICulture == null)
            nativeInitCultureAccessors();

        CultureInfo.CurrentCulture = value;
    }
}

This is in Thread.cs. So you can set the CultureInfo.CurrentCulture property explicitly.

example:

CultureInfo.CurrentCulture = new CultureInfo("en-GB"); ;

Assert.Equal("£1,000.00", String.Format("{0:C}", 1000));

CultureInfo.CurrentCulture = new CultureInfo("en-US"); ;

Assert.Equal("$1,000.00", String.Format("{0:C}", 1000));

csproj file for unit test project:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>netcoreapp1.0</TargetFramework>

    <IsPackable>false</IsPackable>

    <ApplicationIcon />

    <OutputType>Library</OutputType>

    <StartupObject />
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.3.0-preview-20170425-07" />
    <PackageReference Include="xunit" Version="2.2.0" />
    <PackageReference Include="xunit.runner.visualstudio" Version="2.2.0" />
  </ItemGroup>

</Project>

edited Sep 13 '17 at 15:41

answered Sep 13 '17 at 13:35

Aaron Roberts

1,342
10
21

but I *can* spin up new threads in the test case so the tip is worth a +1 even if it's not exactly the correct answer. – bradgonesurfing Sep 13 '17 at 13:49
Fails at runtime ;) – bradgonesurfing Sep 13 '17 at 14:43
I am running VS 2017 with Core 2.0 and the tests are passing (also passed in core 1.1) – Aaron Roberts Sep 13 '17 at 14:46
Hmmm. Let me check. Sandbox is in a mess at the moment. I was sure I got some kind of exception when I tried it. – bradgonesurfing Sep 13 '17 at 14:47
No I just get a build failure with dotnet core app 1.0 ( maybe with 2.0 ) this has been improved ?? https://dl.dropboxusercontent.com/s/ahljp4bqjig3zkl/devenv_2017-09-13_17-23-16.png – bradgonesurfing Sep 13 '17 at 15:23
According to the docs `CultureInfo.CurrentCulture` is read/write as of .Net Framework 4.6, and has always been in .NetCore. Are you sure your project is targeting the correct framework? – Aaron Roberts Sep 13 '17 at 15:40
Can please you post your csproj file so I can see what you have configured. – bradgonesurfing Sep 13 '17 at 15:40
My Bad net461;netcoreapp1.0 upgraded from net451;netcoreapp1.0 works – bradgonesurfing Sep 13 '17 at 15:41
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/154360/discussion-between-aaron-roberts-and-bradgonesurfing). – Aaron Roberts Sep 13 '17 at 15:44
In the examples above the desired culture is obtained by creating a new instance. When you do not intend to modify this instance `CultureInfo.GetCultureInfo("en-GB")` should be used, which gives you a read-only default. – Henk van Boeijen Jun 17 '20 at 10:09

score 0 · Answer 2 · answered Sep 13 '17 at 13:48

The solution is to set

CultureInfo.DefaultThreadCurrentCulture = ci;

and then spin up a new thread. This will set the current culture for the next thread. The final test case is.

[Test]
public void ParsingWithCommaDecimalSeparatorShouldWork()
{
    var ci = new CultureInfo(CultureInfo.CurrentCulture.Name)
             {
                 NumberFormat =
                 {
                     NumberDecimalSeparator = ","
                     , NumberGroupSeparator = "."
                 }
             };

    CultureInfo.DefaultThreadCurrentCulture = ci;
    var result = "";
    var thread = new Thread
        ( delegate()
        {
            Console.WriteLine(CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator);
            Console.WriteLine(CultureInfo.CurrentCulture.NumberFormat.NumberGroupSeparator);

            var t = Template.Parse("{{2.5}}");
            result = t.Render(new Hash(), CultureInfo.InvariantCulture);
        } );
    thread.Start();
    thread.Join();
    Assert.AreEqual(result, "2.5");

}

which is a bit messy but get the job done.

How to set the culture in a dotnetcore xunit test

2 Answers2