I'm working on a PoSh project that generates CSharp code, and then Add-Types it into memory.

The new types use existing types in an on disk DLL, which is loaded via Add-Type.

All is well and good untill I actualy try to invoke methods on the new types. Here's an example of what I'm doing:

$PWD = "."
rm -Force $PWD\TestClassOne*
$code = "
namespace TEST{
public class TestClassOne
{
    public int DoNothing()
    {
        return 1;
    }
}
}"
$code | Out-File tcone.cs
Add-Type -OutputAssembly $PWD\TestClassOne.dll -OutputType Library -Path $PWD\tcone.cs
Add-Type -Path $PWD\TestClassOne.dll
$a = New-Object TEST.TestClassOne
"Using TestClassOne"
$a.DoNothing()


"Compiling TestClassTwo"
Add-Type -Language CSharpVersion3 -TypeDefinition "
namespace TEST{
public class TestClassTwo
{
    public int CallTestClassOne()
    {
        var a = new TEST.TestClassOne();
        return a.DoNothing();
    }
}
}" -ReferencedAssemblies $PWD\TestClassOne.dll
"OK"
$b = New-Object TEST.TestClassTwo
"Using TestClassTwo"
$b.CallTestClassOne()

Running the above script gives the following error on the last line:

Exception calling "CallTestClassOne" with "0" argument(s): "Could not load file or assembly 'TestClassOne,...' or one of its dependencies. The system cannot find the file specified." At AddTypeTest.ps1:39 char:20 + $b.CallTestClassOne <<<< () + CategoryInfo : NotSpecified: (:) [], MethodInvocationException + FullyQualifiedErrorId : DotNetMethodException

What am I doing wrong?