Use dotnet test on linux

test.ps1

@@ -11,15 +11,19 @@ param(
 
 if ($codecov -eq 'true') {
 
-  # xunit doesn't understand custom params so use dotnet test
+  # xunit doesn't understand custom params so use dotnet test.
   # Coverage tests are run in debug because the coverage tools are triggering a JIT error in filter processors
   # that causes the blue component of transformed values to be corrupted.
   dotnet clean -c Debug
   dotnet test -c Debug -f $targetFramework /p:codecov=true
 }
+elseif ($os -ne 'windows-latest') {
+  # xunit doesn't run without mono on linux and macos.
+  dotnet test --no-build -c Release -f $targetFramework
+}
 else {
 
-  # There were issues matching the correct installed runtime if we do not specify it explicitly:
+  # xunit has issues matching the correct installed runtime if we do not specify it explicitly.
   # https://github.com/xunit/xunit/issues/1476
   # This fix assumes the base version is installed.
   $coreTargetFrameworkRegex = '^netcoreapp(\d+\.\d+)$'
@@ -27,16 +31,15 @@ else {
     $fxVersion = "--fx-version ${matches[1]}.0"
   }
 
-  # xunit requires explicit path
+  # xunit requires explicit path.
   Set-Location $env:XUNIT_PATH
 
-  # xunit doesn't actually understand -x64 as an option
+  # xunit doesn't actually understand -x64 as an option.
   if ($platform -ne '-x86') {
     $platform = ''
   }
 
-  dotnet clean -c Release
+  dotnet xunit --no-build -c Release -f $targetFramework ${fxVersion} $platform
-  dotnet xunit -c Release -f $targetFramework ${fxVersion} $platform
 
   Set-Location $PSScriptRoot
 }