Test projects sometimes require <OutputType>Exe</OutputType>

[NTaylorMullen]

Description

Migrating existing test projects from project.json => csproj results in class library based test projects. The problem with this is trying to run dotnet test fails. This doesn't always seem to be a problem because I've also migrated more complex projects that look to work without the <OutputType>Exe</OutputType> requirement (added a repro project to show where it does fail).

Steps to reproduce

• dotnet migrate this super simple project.
• Remove the dotnet-test-xunit dependency from the migrated csproj to work around this issue.
• dotnet restore
• dotnet test

Expected behavior

Microsoft (R) Test Execution Command Line Tool Version 15.0.0.0
Copyright (c) Microsoft Corporation.  All rights reserved.

Starting test execution, please wait...
Passed   Tests.Tests.Test1

Total tests: 1. Passed: 1. Failed: 0. Skipped: 0.
Test Run Successful.
Test execution time: 1.9826 Seconds

Actual behavior

Microsoft (R) Test Execution Command Line Tool Version 15.0.0.0
Copyright (c) Microsoft Corporation.  All rights reserved.

Starting test execution, please wait...
Error: Could not find testhost.dll for source 'C:\Users\nimullen\Documents\temp\TestMigrationProject\bin\Debug\netcoreapp1.1\TestMigrationProject.dll'. Make sure test project has a nuget reference of package "microsoft.testplatform.testhost".

Environment

dotnet --info:

.NET Command Line Tools (1.0.0-preview3-004056)

Product Information:
 Version:            1.0.0-preview3-004056
 Commit SHA-1 hash:  ccc4968bc3

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.14393
 OS Platform: Windows
 RID:         win10-x64

Microsoft.NET.Test.Sdk version tested:
15.0.0-preview-20161024-02

[natemcmaster]

I hit this too. It seems .NET Framework tests will run when <OutputType> is missing, but .NET Core tests fail as Taylor described. Using 15.0.0-preview-20161123-03.

[codito]

This issue is by design. A multitargeted test project should have following structure:

<OutputType Condition=" '$(TargetFramework)' != 'net46' ">Exe</OutputType>
<TargetFrameworks>net46;netcoreapp1.0;netcoreapp1.1</TargetFrameworks>

netXX test projects have always been libraries. netcoreapp test projects need to exe as per dotnet/sdk#201.

[natemcmaster]

Would it make sense to put something like this in Microsoft.NET.Test.SDK?

<OutputType Condition=" $(TargetFramework.StartsWith('netcoreapp') ">Exe</OutputType>

[NTaylorMullen]

Why do desktop targeting test projects need to be console applications? In the past a test project did not need to be a console application in order to work.

[natemcmaster]

IIUC under the hood, the project.json build system had special knowledge about the ‘testRunner’ attribute, and changed compilation slightly to enable unit test to run on .NET Core. (on example: it output the runtimeconfig.json file). I think the experience we’re looking for is that by indicating “this project is a test project”, we’d expect the sdk to figure out things as much as possible…including things such as OutputType.

[codito]

Created #287 as an umbrella issue for discussing the options around this.

[codito]

Closing this in favor of #287