Random build failures: Publish the test logs

[TomFinley]

Companion issue to #1471. As mentioned there we are currently lacking information about test failures.

Our tests actually do produce sizable logs that could conceivably be of help, if we were only able to access them. This includes most notable output files that are compared against baseline files, as well as in many cases the trained models themselves. For example, for a Debug build, and the Microsoft.ML.Core.Tests test, we would want to publish bin/AnyCPU.Debug/Microsoft.ML.Core.Tests/netcoreapp2.1/TestOutput as an artifact of the build. (The same for all tests.) We would of course want the test artifacts for all test assemblies to be published, as well as for either debug and release, as well as for all of the currently supported platform.

We of course used to do this, but this capability was somehow lost when we moved to the new build infrastructure a few months ago I believe.

So for example, if we view this build (note that some will not be able to access this!), we have published this artifact named PackageAssets, as seen below.

This appears at least at first glance to be controlled from this in our repo.

machinelearning/build/vsts-ci.yml

Lines 30 to 35 in a26eca7

	- task: PublishBuildArtifacts@1
	displayName: Publish Linux package assets
	inputs:
	pathToPublish: $(Build.SourcesDirectory)/bin/obj/packages
	artifactName: PackageAssets
	artifactType: container

@eerhardt has already provided some assistance in this area, though as of yet I have been unable to find time to follow up on his hints.

• Documentation on publishing build artifacts.
• A specific example, from Roslyn (not our repo of course), of doing just that.

Our specific .yml configuration files for doing the continuous integration are at the following locations:

• .vsts-dotnet-ci.yml
• build/ci/phase-template.yml
• build/vsts-ci.yml

It may be as simple as following Roslyn's example and modifying build/vsts-ci.yml to just publish a few more things, but I'm not altogether confident of this.

This may be a task best suited to someone with some experience mucking about in these configuration files.

[montebhoover]

Tom, you are exactly right, this will be as simple as modifying build/vsts-ci.yml. I'll make a quick PR to update that and we'll start having access to the build logs produced by the VSTS agents.