System.TestStructs ships with Micrososoft.Extensions.DependencyInjection.Specification.Tests but builds from test directory

[ericstj]

#48858 started shipping System.TestStructs.

Micrososoft.Extensions.DependencyInjection.Specification.Tests is shipped to be used by 3rd party implementers of Micrososoft.Extensions.DependencyInjection in order to test their implementations. This was something done in dotnet/extensions, then dropped when we moved the source to dotnet/runtime, and brought back due to #37108 (comment) cc @maryamariyan @JunTaoLuo

@eerhardt added tests to this test assembly in 21ff47c which require the System.TestStructs assembly in order to test how DI implementations handle structs with parameterless constructors.

@ViktorHofer brought up some questions after we merged the PR and some issues arose around wether we should be shipping System.TestStructs as it is, or if it should be moved somewhere to better indicate that its a test assembly. For example https://github.com/dotnet/runtime/tree/main/src/libraries/Common/src or https://github.com/dotnet/runtime/tree/main/src/libraries/Common/tests.

We might also consider if we want to change the assembly name, public key token, or anything else about how we build this or other "shipping test assemblies".

This issue aims to gather concensus on these questions. Those mentioned, please weigh in.

[ghost]

Tagging subscribers to this area: @safern, @ViktorHofer, @Anipik
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Issue Details

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#48858 started shipping System.TestStructs.

Micrososoft.Extensions.DependencyInjection.Specification.Tests is shipped to be used by 3rd party implementers of Micrososoft.Extensions.DependencyInjection in order to test their implementations. This was something done in dotnet/extensions, then dropped when we moved the source to dotnet/runtime, and brought back due to #37108 (comment) cc @maryamariyan @JunTaoLuo

@eerhardt added tests to this test assembly in 21ff47c which require the System.TestStructs assembly in order to test how DI implementations handle structs which parameterized constructors.

@ViktorHofer brought up some questions after we merged the PR and some issues arose around wether we should be shipping System.TestStructs as it is, or if it should be moved somewhere to better indicate that its a test assembly. For example https://github.com/dotnet/runtime/tree/main/src/libraries/Common/src or https://github.com/dotnet/runtime/tree/main/src/libraries/Common/tests.

We might also consider if we want to change the assembly name, public key token, or anything else about how we build this or other "shipping test assemblies".

This issue aims to gather concensus on these questions. Those mentioned, please weigh in.

Author:	ericstj
Assignees:	-
Labels:	area-Infrastructure-libraries, untriaged
Milestone:	-

[eerhardt]

The test added in 21ff47c did find a behavioral difference in Unity DI container: unitycontainer/microsoft-dependency-injection#87. So it seems like a valuable test.

Note that once the C# feature comes in which allows parameterless constructors on structs, we can remove the dependency on the TestStructs assembly and just create one in the test assembly.

[ViktorHofer]

Note that once the C# feature comes in which allows parameterless constructors on structs, we can remove the dependency on the TestStructs assembly and just create one in the test assembly.

Is that a NET6 deliverable? If yes then I'm fine to wait, otherwise I would prefer to address this issue sooner.

[eerhardt]

Is that a NET6 deliverable?

According to https://github.com/dotnet/roslyn/blob/master/docs/Language%20Feature%20Status.md#c-next, it is currently in progress. @cston @jcouv @333fred could answer if parameterless struct constructors will make it for NET6.

[333fred]

Chuck is working on them. I would expect that they should make it.

[ericstj]

@eerhardt in this case do you want to remove this test for now until we have the language feature?

[ViktorHofer]

Closing as mitigated with b0ba53a.