Agents not copied to project referencing nunit.engine package

[CharliePoole]

When a project references the engine package, the directories containing the various agents are not actually copied to output as intended. @jnm2 and I have had some off-line discussion about this and I'm doing some experimenting to find out if the particular type of target project makes a difference... i.e. sdk or non-sdk, package reference or package.config.

I guess we had never noticed this because we don't consume the package in the console runner. The VS adapter consumes it but only runs tests in-process, so no visible issue has ever arisen.

[CharliePoole]

I built two simple runners using the same code. One targets net45 and the other net5.0. Visual Studio creates a non-sdk-style project using packages.config for net45 and an sdk-style project using package references for net5.0.

I added the nunit.engine nuget package to both projects. Neither project actually copies the content files (which includes the agents) into the output directory.

I ran the net45 project against a .NET framework test. It throws an exception when trying to start a process because the agent is not found where it's expected to be. If I run in process, it succeeds.

I ran the net 5.0 project against a .NET Core 2.1 test. Even though the files are not visible, it is able to use the info available to locate and run the agent files.

[CharliePoole]

It occurs to me that this would not be a problem if all our agents were pluggable extensions. Then the extension service would just find them! I'm experimenting with this approach for TestCentric. See testcentric/testcentric-gui#832

[CharliePoole]

Moved to 4.0 on the basis that the use of pluggable agents is a 4.0 feature.

[manfred-brands]

contentFiles element are not recognized by packages.config projects (NuGet/Home#7672)
You would have to duplicate the files in both the content and contentFiles folders to support both.
Alternatively, would it be better to put those file in a runtime folder as they are needed at runtime?

[CharliePoole]

@manfred-brands See issue #909 for a potential solution to this and some other problems. The issue is an Epic (contains other issues) and I've made some progress on it.