You are working on the solution REPO-ROOT/Test/UnitTest/UnitTest.sln,
therefore SOLUTION-ROOT is REPO-ROOT/Test/UnitTest.
The REPO-ROOT/Test/UnitTest/UnitTest/UnitTest.vcxproj is the unit test project.
When any *.h or *.cpp file is changed, unit test is required to run.
When any test case fails, you must fix the issue immediately, even those errors are unrelated to the issue you are working on.
REPO-ROOT/Test/Linux stores linux configurations for UnitTest.vcxproj.
You need to build, test and debug in that specific folder, otherwise the unit test will not function properly. On Linux, only configuration "debug x64" is available, no need to build or run projects with other configurations.