Change tests to not modify Core_Root (#23470)

Redesign tests that needed to modify Core_Root to no longer do so.

- Loader.FromNativePaths: Use `CORE_LIBRARIES` instead of `COREROOT`
- Loader.AssemblyDependencyResolver: Split out the invalid hosting test that needs hostpolicy to not be preloaded. Have `CoreRun` and `CoreShim` preload hostpolicy when a path to a hostpolicy is specified in the `MOCK_HOSTPOLICY` environment variable.
- Add a `CLRTest.MockHosting.targets` file that is imported when a test requires hostpolicy. It adds the reference to the mock hostpolicy and ensures that the `MOCK_HOSTPOLICY` environment variable is correctly set in the test scripts.

Fixes #23429.

19 files changed, 125 insertions, 134 deletions

diff --git a/tests/src/CLRTest.Execute.Bash.targets b/tests/src/CLRTest.Execute.Bash.targets
index a73f20555c..44dfcdb204 100644
--- a/tests/src/CLRTest.Execute.Bash.targets
+++ b/tests/src/CLRTest.Execute.Bash.targets
@@ -253,7 +253,6 @@ fi
       </PropertyGroup>
       <PropertyGroup>
       <_CLRTestRunFile Condition="'$(CLRTestIsHosted)'=='true'">"$CORE_ROOT/corerun"</_CLRTestRunFile>
-      
       <BashCLRTestLaunchCmds>$(BashIlrtTestLaunchCmds)</BashCLRTestLaunchCmds>
 
       <BashCLRTestLaunchCmds Condition="'$(CLRTestKind)' == 'BuildAndRun'">
diff --git a/tests/src/CLRTest.Execute.targets b/tests/src/CLRTest.Execute.targets
index ff0becbf25..de79609130 100644
--- a/tests/src/CLRTest.Execute.targets
+++ b/tests/src/CLRTest.Execute.targets
@@ -71,6 +71,7 @@ This file contains the logic for providing Execution Script generation.
   <Import Project="CLRTest.CrossGen.targets" />
   <Import Project="CLRTest.GC.targets" />
   <Import Project="CLRTest.Execute.*.targets" />
+  <Import Project="CLRTest.MockHosting.targets" Condition="'$(RequiresMockHostPolicy)' == 'true'" />
   
   <Target Name="GenerateExecutionScriptsInternal"
     Condition="$(_CLRTestNeedsToRun) or $(_CLRTestBuildsExecutable)"
diff --git a/tests/src/CLRTest.MockHosting.targets b/tests/src/CLRTest.MockHosting.targets
new file mode 100644
index 0000000000..a139caaeb8
--- /dev/null
+++ b/tests/src/CLRTest.MockHosting.targets
@@ -0,0 +1,21 @@
+<!--
+***********************************************************************************************
+CLRTest.MockHosting.targets
+
+This file contains the logic for correctly hooking up a mock hostpolicy to a test.
+
+***********************************************************************************************
+-->
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <HostPolicyFileExtension>.so</HostPolicyFileExtension>
+    <HostPolicyFileExtension Condition="'$(TargetsOSX)' =='true'">.dylib</HostPolicyFileExtension>
+  </PropertyGroup>
+  <ItemGroup>
+    <ProjectReference Include="$(MSBuildThisFileDirectory)/Common/hostpolicymock/CMakeLists.txt" />
+    <!-- %28 decodes to '('. It's needed to keep MSBuild from trying to parse $(pwd) as an MSBuild property -->
+    <CLRTestBashEnvironmentVariable Include="export MOCK_HOSTPOLICY=$%28pwd)/hostpolicy$(HostPolicyFileExtension)" />
+    <!-- %25 decodes to '%'. It's needed to keep %cd itself from being decoded since we want '%cd%' directly in the script. -->
+    <CLRTestBatchEnvironmentVariable Include="set MOCK_HOSTPOLICY=%25cd%\hostpolicy.dll" />
+  </ItemGroup>
+</Project>
diff --git a/tests/src/Common/CoreCLRTestLibrary/HostPolicyMock.cs b/tests/src/Common/CoreCLRTestLibrary/HostPolicyMock.cs
index f354d9ab56..0bbce1b6e5 100644
--- a/tests/src/Common/CoreCLRTestLibrary/HostPolicyMock.cs
+++ b/tests/src/Common/CoreCLRTestLibrary/HostPolicyMock.cs
@@ -43,35 +43,8 @@ namespace TestLibrary
         [UnmanagedFunctionPointer(CallingConvention.Cdecl, CharSet = HostpolicyCharSet)]
         public delegate void ErrorWriterDelegate(string message);
 
-        public static string DeleteExistingHostpolicy(string coreRoot)
-        {
-#if REFERENCING_SYSTEMPRIVATECORELIB
-            throw new Exception("This API is not supported when compiled referencing SPCL");
-
-#else
-            string hostPolicyFileName = XPlatformUtils.GetStandardNativeLibraryFileName("hostpolicy");
-            string destinationPath = Path.Combine(coreRoot, hostPolicyFileName);
-
-            if (File.Exists(destinationPath))
-            {
-                File.Delete(destinationPath);
-            }
-
-            return destinationPath;
-#endif
-        }
-
         public static void Initialize(string testBasePath, string coreRoot)
         {
-#if !REFERENCING_SYSTEMPRIVATECORELIB
-            string hostPolicyFileName = XPlatformUtils.GetStandardNativeLibraryFileName("hostpolicy");
-            string destinationPath = DeleteExistingHostpolicy(coreRoot);
-
-            File.Copy(
-                Path.Combine(testBasePath, hostPolicyFileName),
-                destinationPath);
-#endif
-
             _assemblyDependencyResolverType = typeof(AssemblyDependencyResolver);
 
             // This is needed for marshalling of function pointers to work - requires private access to the ADR unfortunately
diff --git a/tests/src/Interop/COM/Activator/Activator.csproj b/tests/src/Interop/COM/Activator/Activator.csproj
index b656a5c1e9..51b0b73ea4 100644
--- a/tests/src/Interop/COM/Activator/Activator.csproj
+++ b/tests/src/Interop/COM/Activator/Activator.csproj
@@ -8,7 +8,7 @@
     <SchemaVersion>2.0</SchemaVersion>
     <OutputType>Exe</OutputType>
     <ReferenceSystemPrivateCoreLib>true</ReferenceSystemPrivateCoreLib>
-
+    <RequiresMockHostPolicy>true</RequiresMockHostPolicy>
     <!-- Test unsupported outside of windows -->
     <TestUnsupportedOutsideWindows>true</TestUnsupportedOutsideWindows>
     <DisableProjectBuild Condition="'$(TargetsWindows)' != 'true'">true</DisableProjectBuild>
@@ -29,7 +29,6 @@
     <ProjectReference Include="Servers\AssemblyB.csproj" />
     <ProjectReference Include="Servers\AssemblyC.csproj" />
     <ProjectReference Include="Servers\AssemblyContracts.csproj" />
-    <ProjectReference Include="../../../Common/hostpolicymock/CMakeLists.txt" />
   </ItemGroup>
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
 
diff --git a/tests/src/Interop/COM/NativeClients/DefaultInterfaces.csproj b/tests/src/Interop/COM/NativeClients/DefaultInterfaces.csproj
index 040ec132bf..f8a5dd6d22 100644
--- a/tests/src/Interop/COM/NativeClients/DefaultInterfaces.csproj
+++ b/tests/src/Interop/COM/NativeClients/DefaultInterfaces.csproj
@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.props))\dir.props" />
-  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), Interop.settings.targets))\Interop.settings.targets" />
   <PropertyGroup>
     <IgnoreCoreCLRTestLibraryDependency>true</IgnoreCoreCLRTestLibraryDependency>
     <CLRTestScriptLocalCoreShim>true</CLRTestScriptLocalCoreShim>
+    <RequiresMockHostPolicy>true</RequiresMockHostPolicy>
 
     <TestUnsupportedOutsideWindows>true</TestUnsupportedOutsideWindows>
     <DisableProjectBuild Condition="'$(TargetsUnix)' == 'true'">true</DisableProjectBuild>
@@ -16,8 +16,8 @@
   <ItemGroup>
     <ProjectReference Include="DefaultInterfaces/CMakeLists.txt" />
     <ProjectReference Include="../NetServer/NetServer.DefaultInterfaces.ilproj" />
-    <ProjectReference Include="../../../Common/hostpolicymock/CMakeLists.txt" />
     <ProjectReference Include="../../../Common/CoreCLRTestLibrary/CoreCLRTestLibrary.csproj" />
   </ItemGroup>
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), Interop.settings.targets))\Interop.settings.targets" />
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
-</Project>
\ No newline at end of file
+</Project>
diff --git a/tests/src/Interop/COM/NativeClients/Licensing.csproj b/tests/src/Interop/COM/NativeClients/Licensing.csproj
index dba48db706..3bebdce282 100644
--- a/tests/src/Interop/COM/NativeClients/Licensing.csproj
+++ b/tests/src/Interop/COM/NativeClients/Licensing.csproj
@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.props))\dir.props" />
-  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), Interop.settings.targets))\Interop.settings.targets" />
   <PropertyGroup>
     <IgnoreCoreCLRTestLibraryDependency>true</IgnoreCoreCLRTestLibraryDependency>
     <CLRTestScriptLocalCoreShim>true</CLRTestScriptLocalCoreShim>
+    <RequiresMockHostPolicy>true</RequiresMockHostPolicy>
 
     <TestUnsupportedOutsideWindows>true</TestUnsupportedOutsideWindows>
     <DisableProjectBuild Condition="'$(TargetsUnix)' == 'true'">true</DisableProjectBuild>
@@ -16,8 +16,8 @@
   <ItemGroup>
     <ProjectReference Include="Licensing/CMakeLists.txt" />
     <ProjectReference Include="../NetServer/NetServer.csproj" />
-    <ProjectReference Include="../../../Common/hostpolicymock/CMakeLists.txt" />
     <ProjectReference Include="../../../Common/CoreCLRTestLibrary/CoreCLRTestLibrary.csproj" />
   </ItemGroup>
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), Interop.settings.targets))\Interop.settings.targets" />
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
-</Project>
\ No newline at end of file
+</Project>
diff --git a/tests/src/Interop/COM/NativeClients/Primitives.csproj b/tests/src/Interop/COM/NativeClients/Primitives.csproj
index 305f1048b3..932fdb7342 100644
--- a/tests/src/Interop/COM/NativeClients/Primitives.csproj
+++ b/tests/src/Interop/COM/NativeClients/Primitives.csproj
@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.props))\dir.props" />
-  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), Interop.settings.targets))\Interop.settings.targets" />
   <PropertyGroup>
     <IgnoreCoreCLRTestLibraryDependency>true</IgnoreCoreCLRTestLibraryDependency>
     <CLRTestScriptLocalCoreShim>true</CLRTestScriptLocalCoreShim>
+    <RequiresMockHostPolicy>true</RequiresMockHostPolicy>
 
     <TestUnsupportedOutsideWindows>true</TestUnsupportedOutsideWindows>
     <DisableProjectBuild Condition="'$(TargetsUnix)' == 'true'">true</DisableProjectBuild>
@@ -16,8 +16,8 @@
   <ItemGroup>
     <ProjectReference Include="Primitives/CMakeLists.txt" />
     <ProjectReference Include="../NetServer/NetServer.csproj" />
-    <ProjectReference Include="../../../Common/hostpolicymock/CMakeLists.txt" />
     <ProjectReference Include="../../../Common/CoreCLRTestLibrary/CoreCLRTestLibrary.csproj" />
   </ItemGroup>
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), Interop.settings.targets))\Interop.settings.targets" />
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
-</Project>
\ No newline at end of file
+</Project>
diff --git a/tests/src/Interop/IJW/LoadIjwFromModuleHandle/LoadIjwFromModuleHandle.csproj b/tests/src/Interop/IJW/LoadIjwFromModuleHandle/LoadIjwFromModuleHandle.csproj
index 395a81c286..165826ccd8 100644
--- a/tests/src/Interop/IJW/LoadIjwFromModuleHandle/LoadIjwFromModuleHandle.csproj
+++ b/tests/src/Interop/IJW/LoadIjwFromModuleHandle/LoadIjwFromModuleHandle.csproj
@@ -12,6 +12,7 @@
     <SolutionDir Condition="$(SolutionDir) == '' Or $(SolutionDir) == '*Undefined*'">..\..\</SolutionDir>
     <ReferenceSystemPrivateCoreLib>true</ReferenceSystemPrivateCoreLib>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <RequiresMockHostPolicy>true</RequiresMockHostPolicy>
 
     <!-- IJW is Windows-only -->
     <!-- Test unsupported outside of windows -->
@@ -43,7 +44,6 @@
   <ItemGroup>
     <ProjectReference Include="../IjwNativeCallingManagedDll/CMakeLists.txt" />
     <ProjectReference Include="../ijwhostmock/CMakeLists.txt" />
-    <ProjectReference Include="../../../Common/hostpolicymock/CMakeLists.txt" />
   </ItemGroup>
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), Interop.settings.targets))\Interop.settings.targets" />
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
diff --git a/tests/src/Interop/Interop.settings.targets b/tests/src/Interop/Interop.settings.targets
index fc906f200d..f67ae45432 100644
--- a/tests/src/Interop/Interop.settings.targets
+++ b/tests/src/Interop/Interop.settings.targets
@@ -4,11 +4,6 @@
     <InteropCommonDir>$(MSBuildThisFileDirectory)common/</InteropCommonDir>
   </PropertyGroup>
 
-  <!-- Environment properties -->
-  <PropertyGroup>
-    <DefineConstants Condition="'$(ReferenceSystemPrivateCoreLib)' == 'true'">$(DefineConstants);REFERENCING_SYSTEMPRIVATECORELIB</DefineConstants>
-  </PropertyGroup>
-
   <!-- Add the CoreCLRTestLibrary dependency -->
   <ItemGroup Condition="('$(IgnoreCoreCLRTestLibraryDependency)' != 'true') And ('$(ReferenceSystemPrivateCoreLib)' != 'true')">
     <ProjectReference
@@ -20,7 +15,7 @@
        Compile in relevant files used for testing interop. -->
   <ItemGroup Condition="('$(IgnoreCoreCLRTestLibraryDependency)' != 'true') And ('$(ReferenceSystemPrivateCoreLib)' == 'true')">
     <Compile Include="$(MSBuildThisFileDirectory)\..\Common\CoreCLRTestLibrary\Assertion.cs" />
-    <Compile Include="$(MSBuildThisFileDirectory)\..\Common\CoreCLRTestLibrary\HostPolicyMock.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)\..\Common\CoreCLRTestLibrary\HostPolicyMock.cs" Condition="'$(RequiresMockHostPolicy)' == 'true'"/>
     <Compile Include="$(MSBuildThisFileDirectory)\..\Common\CoreCLRTestLibrary\XPlatformUtils.cs" />
   </ItemGroup>
 
diff --git a/tests/src/Loader/AssemblyDependencyResolverTests/AssemblyDependencyResolverTests.cs b/tests/src/Loader/AssemblyDependencyResolver/AssemblyDependencyResolverTests/AssemblyDependencyResolverTests.cs
index 3e74a6627d..1b6e2a2a7a 100644
--- a/tests/src/Loader/AssemblyDependencyResolverTests/AssemblyDependencyResolverTests.cs
+++ b/tests/src/Loader/AssemblyDependencyResolver/AssemblyDependencyResolverTests/AssemblyDependencyResolverTests.cs
@@ -312,10 +312,6 @@ namespace AssemblyDependencyResolverTests
         public static int Main()
         {
             return TestBase.RunTests(
-                // It's important that the invalid hosting test runs first as it relies on the ability
-                // to delete (if it's there) the hostpolicy.dll. All other tests will end up loading the dll
-                // and thus locking it.
-                typeof(InvalidHostingTest),
                 typeof(AssemblyDependencyResolverTests),
                 typeof(NativeDependencyTests));
         }
diff --git a/tests/src/Loader/AssemblyDependencyResolverTests/AssemblyDependencyResolverTests.csproj b/tests/src/Loader/AssemblyDependencyResolver/AssemblyDependencyResolverTests/AssemblyDependencyResolverTests.csproj
index e2dd0a4df3..0564626a6a 100644
--- a/tests/src/Loader/AssemblyDependencyResolverTests/AssemblyDependencyResolverTests.csproj
+++ b/tests/src/Loader/AssemblyDependencyResolver/AssemblyDependencyResolverTests/AssemblyDependencyResolverTests.csproj
@@ -8,18 +8,15 @@
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
     <ProjectTypeGuids>{786C830F-07A1-408B-BD7F-6EE04809D6DB};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
-    <!-- The test fails if ran twice in the same process. In one of the test cases, it expects a hostpolicy to not to be found, but it actually is found in the second pass -->
-    <UnloadabilityIncompatible>true</UnloadabilityIncompatible>
+    <RequiresMockHostPolicy>true</RequiresMockHostPolicy>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="AssemblyDependencyResolverTests.cs" />
-    <Compile Include="InvalidHostingTest.cs" />
     <Compile Include="NativeDependencyTests.cs" />
     <Compile Include="TestBase.cs" />
   </ItemGroup>
   <ItemGroup>
-    <ProjectReference Include="../../Common/CoreCLRTestLibrary/CoreCLRTestLibrary.csproj" />
-    <ProjectReference Include="../../Common/hostpolicymock/CMakeLists.txt" />
+    <ProjectReference Include="../../../Common/CoreCLRTestLibrary/CoreCLRTestLibrary.csproj" />
   </ItemGroup>
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
 </Project>
diff --git a/tests/src/Loader/AssemblyDependencyResolverTests/NativeDependencyTests.cs b/tests/src/Loader/AssemblyDependencyResolver/AssemblyDependencyResolverTests/NativeDependencyTests.cs
index e7ac906e02..e7ac906e02 100644
--- a/tests/src/Loader/AssemblyDependencyResolverTests/NativeDependencyTests.cs
+++ b/tests/src/Loader/AssemblyDependencyResolver/AssemblyDependencyResolverTests/NativeDependencyTests.cs
diff --git a/tests/src/Loader/AssemblyDependencyResolverTests/TestBase.cs b/tests/src/Loader/AssemblyDependencyResolver/AssemblyDependencyResolverTests/TestBase.cs
index 74532c6a78..74532c6a78 100644
--- a/tests/src/Loader/AssemblyDependencyResolverTests/TestBase.cs
+++ b/tests/src/Loader/AssemblyDependencyResolver/AssemblyDependencyResolverTests/TestBase.cs
diff --git a/tests/src/Loader/AssemblyDependencyResolver/MissingHostPolicyTests/InvalidHostingTest.cs b/tests/src/Loader/AssemblyDependencyResolver/MissingHostPolicyTests/InvalidHostingTest.cs
new file mode 100644
index 0000000000..892fe7be48
--- /dev/null
+++ b/tests/src/Loader/AssemblyDependencyResolver/MissingHostPolicyTests/InvalidHostingTest.cs
@@ -0,0 +1,43 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+using System;
+using System.IO;
+using System.Runtime.Loader;
+using TestLibrary;
+using Xunit;
+
+using Assert = Xunit.Assert;
+
+namespace AssemblyDependencyResolverTests
+{
+    class InvalidHostingTest
+    {        
+        public static int Main(string [] args)
+        {
+            try
+            {
+                string assemblyLocation = typeof(InvalidHostingTest).Assembly.Location;
+                string testBasePath = Path.GetDirectoryName(assemblyLocation);
+                string componentDirectory = Path.Combine(testBasePath, $"InvalidHostingComponent_{Guid.NewGuid().ToString().Substring(0, 8)}");
+                Directory.CreateDirectory(componentDirectory);
+                string componentAssemblyPath = Path.Combine(componentDirectory, "InvalidHostingComponent.dll");
+                File.WriteAllText(componentAssemblyPath, "Mock assembly");
+                
+                object innerException = Assert.Throws<InvalidOperationException>(() =>
+                {
+                    AssemblyDependencyResolver resolver = new AssemblyDependencyResolver(
+                        Path.Combine(testBasePath, componentAssemblyPath));
+                }).InnerException;
+
+                Assert.IsType<DllNotFoundException>(innerException);
+            }
+            catch (Exception ex)
+            {
+                Console.WriteLine(ex);
+                return 101;
+            }
+            return 100;
+        }
+    }
+}
diff --git a/tests/src/Loader/AssemblyDependencyResolver/MissingHostPolicyTests/MissingHostPolicyTests.csproj b/tests/src/Loader/AssemblyDependencyResolver/MissingHostPolicyTests/MissingHostPolicyTests.csproj
new file mode 100644
index 0000000000..f165028c1a
--- /dev/null
+++ b/tests/src/Loader/AssemblyDependencyResolver/MissingHostPolicyTests/MissingHostPolicyTests.csproj
@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.props))\dir.props" />  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <CLRTestKind>BuildAndRun</CLRTestKind>
+    <CLRTestPriority>1</CLRTestPriority>
+    <ProjectGuid>{ABB86728-A3E0-4489-BD97-A0BAB00B322F}</ProjectGuid>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectTypeGuids>{786C830F-07A1-408B-BD7F-6EE04809D6DB};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="InvalidHostingTest.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="../../../Common/CoreCLRTestLibrary/CoreCLRTestLibrary.csproj" />
+  </ItemGroup>
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
+</Project>
diff --git a/tests/src/Loader/AssemblyDependencyResolverTests/InvalidHostingTest.cs b/tests/src/Loader/AssemblyDependencyResolverTests/InvalidHostingTest.cs
deleted file mode 100644
index d1fc56ecf4..0000000000
--- a/tests/src/Loader/AssemblyDependencyResolverTests/InvalidHostingTest.cs
+++ /dev/null
@@ -1,71 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-using System;
-using System.IO;
-using System.Runtime.Loader;
-using TestLibrary;
-using Xunit;
-
-using Assert = Xunit.Assert;
-
-namespace AssemblyDependencyResolverTests
-{
-    class InvalidHostingTest : TestBase
-    {
-        private string _componentDirectory;
-        private string _componentAssemblyPath;
-        private string _officialHostPolicyPath;
-        private string _localHostPolicyPath;
-        private string _renamedHostPolicyPath;
-
-        protected override void Initialize()
-        {
-            // Make sure there's no hostpolicy available
-            _officialHostPolicyPath = HostPolicyMock.DeleteExistingHostpolicy(CoreRoot);
-            string hostPolicyFileName = XPlatformUtils.GetStandardNativeLibraryFileName("hostpolicy");
-            _localHostPolicyPath = Path.Combine(TestBasePath, hostPolicyFileName);
-            _renamedHostPolicyPath = Path.Combine(TestBasePath, hostPolicyFileName + "_renamed");
-            if (File.Exists(_renamedHostPolicyPath))
-            {
-                File.Delete(_renamedHostPolicyPath);
-            }
-            File.Move(_localHostPolicyPath, _renamedHostPolicyPath);
-
-            _componentDirectory = Path.Combine(TestBasePath, $"InvalidHostingComponent_{Guid.NewGuid().ToString().Substring(0, 8)}");
-            Directory.CreateDirectory(_componentDirectory);
-            _componentAssemblyPath = Path.Combine(_componentDirectory, "InvalidHostingComponent.dll");
-            File.WriteAllText(_componentAssemblyPath, "Mock assembly");
-        }
-
-        protected override void Cleanup()
-        {
-            if (Directory.Exists(_componentDirectory))
-            {
-                Directory.Delete(_componentDirectory, recursive: true);
-            }
-
-            if (File.Exists(_renamedHostPolicyPath))
-            {
-                File.Move(_renamedHostPolicyPath, _localHostPolicyPath);
-            }
-        }
-
-        public void TestMissingHostPolicy()
-        {
-            object innerException = Assert.Throws<InvalidOperationException>(() =>
-            {
-                AssemblyDependencyResolver resolver = new AssemblyDependencyResolver(
-                    Path.Combine(TestBasePath, _componentAssemblyPath));
-            }).InnerException;
-
-            Assert.IsType<DllNotFoundException>(innerException);
-        }
-
-        // Note: No good way to test the missing entry point case where hostpolicy.dll
-        // exists, but it doesn't have the right entry points.
-        // Loading a "wrong" hostpolicy.dll into the process is non-revertable operation
-        // so we would not be able to run other tests along side this one.
-        // Having a standalone .exe just for that one test is not worth it.
-    }
-}
diff --git a/tests/src/Loader/NativeLibs/FromNativePaths.cs b/tests/src/Loader/NativeLibs/FromNativePaths.cs
index 7f9975311c..29e7a5486a 100644
--- a/tests/src/Loader/NativeLibs/FromNativePaths.cs
+++ b/tests/src/Loader/NativeLibs/FromNativePaths.cs
@@ -5,6 +5,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Runtime.InteropServices;
 
 public class FromNativePaths
@@ -29,17 +30,21 @@ public class FromNativePaths
         // search paths for corerun include the folder where corerun resides. Move the native library there to verify that it
         // can be loaded from there.
 
-        var coreRoot = Environment.GetEnvironmentVariable("CORE_ROOT");
-        if (string.IsNullOrWhiteSpace(coreRoot))
+        var coreLibraries = Environment.GetEnvironmentVariable("CORE_LIBRARIES");
+        if (string.IsNullOrWhiteSpace(coreLibraries))
         {
-            Console.WriteLine("FromNativePaths failed: CORE_ROOT is not defined.");
+            Console.WriteLine("FromNativePaths failed: CORE_LIBRARIES is not defined.");
             return false;
         }
-        if (!Directory.Exists(coreRoot))
+
+        // In case there were multiple paths in CORE_LIBRARIES, assume that the last one is the one added in the test script.
+        coreLibraries = coreLibraries.Split(new [] {TestLibrary.Utilities.IsWindows ? ';' : ':'}, StringSplitOptions.RemoveEmptyEntries).Last();
+
+        if (!Directory.Exists(coreLibraries))
         {
             Console.WriteLine(
-                "FromNativePaths failed: Directory specified by CORE_ROOT does not exist: {0}",
-                coreRoot);
+                "FromNativePaths failed: Directory specified by CORE_LIBRARIES does not exist: {0}",
+                coreLibraries);
             return false;
         }
 
@@ -51,7 +56,7 @@ public class FromNativePaths
             if (!File.Exists(nativeLibraryName))
                 continue;
 
-            var destinationPath = Path.Combine(coreRoot, nativeLibraryName);
+            var destinationPath = Path.Combine(coreLibraries, nativeLibraryName);
             try
             {
                 var destinationFileInfo = new FileInfo(destinationPath);
diff --git a/tests/src/Loader/NativeLibs/FromNativePaths.csproj b/tests/src/Loader/NativeLibs/FromNativePaths.csproj
index c607beb4e4..5ce7e02a60 100644
--- a/tests/src/Loader/NativeLibs/FromNativePaths.csproj
+++ b/tests/src/Loader/NativeLibs/FromNativePaths.csproj
@@ -18,7 +18,21 @@
     <Compile Include="FromNativePaths.cs" />
   </ItemGroup>
   <ItemGroup>
+    <ProjectReference Include="..\..\Common\CoreCLRTestLibrary\CoreCLRTestLibrary.csproj" />
     <ProjectReference Include="CMakeLists.txt" />
   </ItemGroup>
+  <ItemGroup>
+    <CLRTestBashEnvironmentVariable Include="export CORE_LIBRARIES=$CORE_LIBRARIES:$%28pwd)/Subdirectory" />
+    <CLRTestBatchEnvironmentVariable Include="set CORE_LIBRARIES=$CORE_LIBRARIES%3B%25cd%\\Subdirectory" />
+  </ItemGroup>
+  <PropertyGroup>
+    <PathEnvSetupCommands>
+    <![CDATA[
+      mkdir Subdirectory
+      ]]>
+    </PathEnvSetupCommands>
+    <BashCLRTestPreCommands>$(BashCLRTestPreCommands);$(PathEnvSetupCommands)</BashCLRTestPreCommands>
+    <CLRTestBatchPreCommands>$(BatchCLRTestPreCommands);$(PathEnvSetupCommands)</CLRTestBatchPreCommands>
+  </PropertyGroup>
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
-</Project>
\ No newline at end of file
+</Project>