Unable to add trimming tests for OOB assemblies

[steveharter]

When trimming tests are added to an OOB assembly, such as System.Data.OleDb, the build\test command results in error messages like this due to the source assembly not being found. This is due to missing target architecture in the path:

C:\git\ComponentModel\.dotnet\sdk\9.0.100-preview.3.24204.13\Microsoft.Common.CurrentVersion.targets(4983,5): error MSB3030: Could not copy the file "C:\git\ComponentModel\artifacts\bin\System.Data.Odbc\Release\net9.0\System.Data.
Odbc.dll" because it was not found. [C:\git\ComponentModel\artifacts\bin\trimmingTests\projects\System.Data.Odbc.TrimmingTests\OdbcParameterTest\win-x64\project.csproj]

In this case, there is no net9.0 subfolder, but there is net9.0-windows, net9.0-unix, etc.

FWIW adding trimming tests include:

• Adding a ILLink.Descriptors.xml file to the library's tests folder with a reference to that in the test's cproj file like this:
  • <TrimmerRootDescriptor Include="$(MSBuildThisFileDirectory)ILLink.Descriptors.xml" />
• Adding a TrimmingTests folder to the library's tests folder which includes a .proj file as well as .cs files for the tests.
• Building like this:
  • build.cmd -s libs.tests /p:TestAssemblies=false /p:TestTrimming=true

Linking #102244 for the need to add OOB trimming tests.

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[ericstj]

I wonder if this is due to how the test is referencing the src library? @steveharter could you share the change you tried that didn't work here?

FWIW, I see the product test uses the following frameworks.

runtime/src/libraries/System.Data.OleDb/tests/System.Data.OleDb.Tests.csproj

Line 3 in a4407a1

<TargetFrameworks>$(NetCoreAppCurrent)-windows;$(NetFrameworkMinimum)</TargetFrameworks>

I could imagine if the trimming test wasn't using the same it might hit a case where the assembly it needed wasn't built in a vertical build - since the vertical build will only build a subset of the frameworks.