diff --git a/clr_loader/netfx.py b/clr_loader/netfx.py
index 24460ca..4efe841 100644
--- a/clr_loader/netfx.py
+++ b/clr_loader/netfx.py
@@ -14,13 +14,15 @@ def __init__(
     ):
         initialize()
         if config_file is not None:
-            config_file_s = str(config_file)
+            config_file_s = str(config_file).encode("utf8")
         else:
             config_file_s = ffi.NULL
 
+        domain_s = domain.encode("utf8") if domain else ffi.NULL
+
         self._domain_name = domain
         self._config_file = config_file
-        self._domain = _FW.pyclr_create_appdomain(domain or ffi.NULL, config_file_s)
+        self._domain = _FW.pyclr_create_appdomain(domain_s, config_file_s)
 
     def info(self) -> RuntimeInfo:
         return RuntimeInfo(
@@ -41,6 +43,11 @@ def _get_callable(self, assembly_path: StrOrPath, typename: str, function: str):
             function.encode("utf8"),
         )
 
+        if func == ffi.NULL:
+            raise RuntimeError(
+                f"Failed to resolve {typename}.{function} from {assembly_path}"
+            )
+
         return func
 
     def shutdown(self):
diff --git a/netfx_loader/ClrLoader.cs b/netfx_loader/ClrLoader.cs
index af89cee..32b4c01 100644
--- a/netfx_loader/ClrLoader.cs
+++ b/netfx_loader/ClrLoader.cs
@@ -32,8 +32,10 @@ public static IntPtr CreateAppDomain(
             {
                 var setup = new AppDomainSetup
                 {
+                    ApplicationBase = AppDomain.CurrentDomain.BaseDirectory,
                     ConfigurationFile = configFile
                 };
+                Print($"Base: {AppDomain.CurrentDomain.BaseDirectory}");
                 var domain = AppDomain.CreateDomain(name, null, setup);
 
                 Print($"Located domain {domain}");
diff --git a/tests/test_common.py b/tests/test_common.py
index a33dec0..8a9e36d 100644
--- a/tests/test_common.py
+++ b/tests/test_common.py
@@ -76,27 +76,15 @@ def test_coreclr(example_netcore: Path):
 
 
 def test_coreclr_properties(example_netcore: Path):
-    from multiprocessing import get_context
-
-    p = get_context("spawn").Process(
-        target=_do_test_coreclr_autogenerated_runtimeconfig,
-        args=(example_netstandard,),
-        kwargs=dict(properties=dict(APP_CONTEXT_BASE_DIRECTORY=str(example_netcore))),
+    run_in_subprocess(
+        _do_test_coreclr_autogenerated_runtimeconfig,
+        example_netstandard,
+        properties=dict(APP_CONTEXT_BASE_DIRECTORY=str(example_netcore)),
     )
-    p.start()
-    p.join()
-    p.close()
 
 
 def test_coreclr_autogenerated_runtimeconfig(example_netstandard: Path):
-    from multiprocessing import get_context
-
-    p = get_context("spawn").Process(
-        target=_do_test_coreclr_autogenerated_runtimeconfig, args=(example_netstandard,)
-    )
-    p.start()
-    p.join()
-    p.close()
+    run_in_subprocess(_do_test_coreclr_autogenerated_runtimeconfig, example_netstandard)
 
 
 def _do_test_coreclr_autogenerated_runtimeconfig(
@@ -114,25 +102,31 @@ def _do_test_coreclr_autogenerated_runtimeconfig(
     sys.platform != "win32", reason=".NET Framework only exists on Windows"
 )
 def test_netfx(example_netstandard: Path):
-    from clr_loader import get_netfx
-
-    netfx = get_netfx()
-    asm = netfx.get_assembly(example_netstandard / "example.dll")
-
-    run_tests(asm)
+    run_in_subprocess(_do_test_netfx, example_netstandard)
 
 
 @pytest.mark.skipif(
     sys.platform != "win32", reason=".NET Framework only exists on Windows"
 )
 def test_netfx_chinese_path(example_netstandard: Path, tmpdir_factory):
-    from clr_loader import get_netfx
-
     tmp_path = Path(tmpdir_factory.mktemp("example-中国"))
     shutil.copytree(example_netstandard, tmp_path, dirs_exist_ok=True)
 
-    netfx = get_netfx()
-    asm = netfx.get_assembly(os.path.join(example_netstandard, "example.dll"))
+    run_in_subprocess(_do_test_netfx, tmp_path)
+
+
+@pytest.mark.skipif(
+    sys.platform != "win32", reason=".NET Framework only exists on Windows"
+)
+def test_netfx_separate_domain(example_netstandard):
+    run_in_subprocess(_do_test_netfx, example_netstandard, domain="some domain")
+
+
+def _do_test_netfx(example_netstandard, **kwargs):
+    from clr_loader import get_netfx
+
+    netfx = get_netfx(**kwargs)
+    asm = netfx.get_assembly(example_netstandard / "example.dll")
 
     run_tests(asm)
 
@@ -142,3 +136,12 @@ def run_tests(asm):
     test_data = b"testy mctestface"
     res = func(test_data)
     assert res == len(test_data)
+
+
+def run_in_subprocess(func, *args, **kwargs):
+    from multiprocessing import get_context
+
+    p = get_context("spawn").Process(target=func, args=args, kwargs=kwargs)
+    p.start()
+    p.join()
+    p.close()