Unable to get coverage when running tests with Microsoft.AspNetCore.Mvc.Testing

Hello there, I have an issue with a simple repro solution: Three projects :

• WebApp (netcoreapp3.1 with aspnetcore, very simple api)
• Business (netstandard2.0 with only one static class/method)
• Tests (netcoreapp3.1 with xunit and two tests)

The first test instantiate my api controller executes the method and assert on the result. The second one do almost the same but by instantiating the whole aspnetcore pipeline via the WebApplicationFactory.

The version are as follows:

coverlet.msbuild Version="2.9.0"
Microsoft.AspNetCore.Mvc.Testing Version="3.1.5"
Microsoft.NET.Test.Sdk Version="16.6.1"
xunit Version="2.4.1"
xunit.runner.visualstudio Version="2.4.2"

public class UnitTest1
{
    [Fact]
    public void Test1()
    {
        var sut = new DataController();
        var actionResult = sut.Get() as OkObjectResult;
        Assert.NotNull(actionResult);
        Assert.StartsWith("H", (string)actionResult.Value);
        Assert.EndsWith("!", (string)actionResult.Value);
        var t = typeof(WebApplicationFactory<Startup>);
    }

    //[Fact(Skip = "meh")]
    [Fact]
    public async Task Test2()
    {
        var webApplicationFactory = new WebApplicationFactory<Startup>()
            .WithWebHostBuilder(builder =>
            {
                builder.UseEnvironment("Development");
            });
        using var client = webApplicationFactory.CreateClient();
        var r = await client.GetAsync("data");
        var c = await r.Content.ReadAsStringAsync();
        Assert.StartsWith("H", c);
        Assert.EndsWith("!", c);
        r.EnsureSuccessStatusCode();
    }
}

When I run as is I got this coverage :

dotnet test .\Tests\Tests.csproj -p:CollectCoverage=true -p:CoverletOutputFormat="json%2copencover%2ccobertura"

+----------+--------+--------+--------+
| Module   | Line   | Branch | Method |
+----------+--------+--------+--------+
| Business | 0%     | 0%     | 0%     |
+----------+--------+--------+--------+
| WebApp   | 86,36% | 100%   | 80%    |
+----------+--------+--------+--------+

When I skip Test2 I got this coverage:

dotnet test .\Tests\Tests.csproj -p:CollectCoverage=true -:CoverletOutputFormat="json%2copencover%2ccobertura"

+----------+--------+--------+--------+
| Module   | Line   | Branch | Method |
+----------+--------+--------+--------+
| Business | 71,42% | 50%    | 100%   |
+----------+--------+--------+--------+
| WebApp   | 18,18% | 100%   | 20%    |
+----------+--------+--------+--------+

It seems that hosting with WebApplicationFactory makes the coverage unavailable. I can provide the whole solution if needed.

My env :

> dotnet --version
3.1.400-preview-015178

> [System.Environment]::OSVersion.Version
Major  Minor  Build  Revision
-----  -----  -----  --------
10     0      19042  0

[MarcoRossignoli]

We’re working on some solutions, but I don’t have eta at the moment, btw you can use a trick used by one of our user https://github.com/coverlet-coverage/coverlet/pull/225#issuecomment-573896446

Also check if your coverage report generator can merge files like reportgenerator https://www.palmmedia.de/OpenSource/ReportGenerator

[MarcoRossignoli]

I can provide the whole solution if needed.

Could be related to known issue https://github.com/coverlet-coverage/coverlet/blob/master/Documentation/KnownIssues.md#1-vstest-stops-process-execution-earlydotnet-test Can you try with collectors integration? https://github.com/coverlet-coverage/coverlet/blob/master/Documentation/VSTestIntegration.md

It it doesn’t work please can you provide the solution so I can test on my local?