diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/TextureExportManager.cs b/Assets/UniGLTF/Runtime/UniGLTF/IO/TextureExportManager.cs
index 54806083e..f8208be4b 100644
--- a/Assets/UniGLTF/Runtime/UniGLTF/IO/TextureExportManager.cs
+++ b/Assets/UniGLTF/Runtime/UniGLTF/IO/TextureExportManager.cs
@@ -33,12 +33,11 @@ namespace UniGLTF
 
         public TextureExportManager(IEnumerable<Texture> textures)
         {
-            /*
             if (textures == null)
             {
-                throw new System.ArgumentNullException();
+                // empty list for UnitTest
+                textures = new Texture[] { };
             }
-			*/
             m_textures = textures.ToList();
             m_exportTextures = new List<Texture>(Enumerable.Repeat<Texture>(null, m_textures.Count));
         }
diff --git a/Assets/VRM.Samples/Editor/Tests/VRMImportExportTests.cs b/Assets/VRM.Samples/Editor/Tests/VRMImportExportTests.cs
index ebbcf2b28..136c0a197 100644
--- a/Assets/VRM.Samples/Editor/Tests/VRMImportExportTests.cs
+++ b/Assets/VRM.Samples/Editor/Tests/VRMImportExportTests.cs
@@ -10,10 +10,10 @@ namespace VRM.Samples
 {
     public static class JsonExtensions
     {
-        public static void SetValue<T>(this JsonNode node, string key, T value, Action<JsonFormatter, T> seri)
+        public static void SetValue<T>(this JsonNode node, string key, T value, Action<JsonFormatter, T> serialize)
         {
             var f = new JsonFormatter();
-            seri(f, value);
+            serialize(f, value);
             var p = Utf8String.From(key);
             var bytes = f.GetStoreBytes();
             node.SetValue(p, bytes);
diff --git a/Assets/VRM.Samples/Editor/Tests/VRMMaterialTests.cs b/Assets/VRM.Samples/Editor/Tests/VRMMaterialTests.cs
index 9032d6d40..d9aa3031d 100644
--- a/Assets/VRM.Samples/Editor/Tests/VRMMaterialTests.cs
+++ b/Assets/VRM.Samples/Editor/Tests/VRMMaterialTests.cs
@@ -6,67 +6,62 @@ namespace VRM.Samples
 {
     public class VRMMaterialTests
     {
-        /*
+        static UniGLTF.glTFMaterial ExportLoaded(string resourceName)
+        {
+            var material = Resources.Load<Material>(resourceName);
+            var exporter = new VRMMaterialExporter();
+            var textureManager = new UniGLTF.TextureExportManager(null);
+            var exported = exporter.ExportMaterial(material, textureManager);
+
+            // parse glTFExtensionExport to glTFExtensionImport
+            exported.extensions = exported.extensions.Deserialize();
+
+            return exported;
+        }
+
         [Test]
         public void ExportTest()
         {
             {
-                var material = Resources.Load<Material>("Materials/vrm_unlit_texture");
-                var exporter = new VRMMaterialExporter();
-                var exported = exporter.ExportMaterial(material, null);
-                Assert.NotNull(exported.extensions.KHR_materials_unlit);
+                var exported = ExportLoaded("Materials/vrm_unlit_texture");
+                Assert.True(UniGLTF.glTF_KHR_materials_unlit.IsEnable(exported));
                 Assert.AreEqual("OPAQUE", exported.alphaMode);
             }
             {
-                var material = Resources.Load<Material>("Materials/vrm_unlit_transparent");
-                var exporter = new VRMMaterialExporter();
-                var exported = exporter.ExportMaterial(material, null);
-                Assert.NotNull(exported.extensions.KHR_materials_unlit);
+                var exported = ExportLoaded("Materials/vrm_unlit_transparent");
+                Assert.True(UniGLTF.glTF_KHR_materials_unlit.IsEnable(exported));
                 Assert.AreEqual("BLEND", exported.alphaMode);
             }
             {
-                var material = Resources.Load<Material>("Materials/vrm_unlit_cutout");
-                var exporter = new VRMMaterialExporter();
-                var exported = exporter.ExportMaterial(material, null);
-                Assert.NotNull(exported.extensions.KHR_materials_unlit);
+                var exported = ExportLoaded("Materials/vrm_unlit_cutout");
+                Assert.True(UniGLTF.glTF_KHR_materials_unlit.IsEnable(exported));
                 Assert.AreEqual("MASK", exported.alphaMode);
             }
             {
-                var material = Resources.Load<Material>("Materials/vrm_unlit_transparent_zwrite");
-                var exporter = new VRMMaterialExporter();
-                var exported = exporter.ExportMaterial(material, null);
-                Assert.NotNull(exported.extensions.KHR_materials_unlit);
+                var exported = ExportLoaded("Materials/vrm_unlit_transparent_zwrite");
+                Assert.True(UniGLTF.glTF_KHR_materials_unlit.IsEnable(exported));
                 Assert.AreEqual("BLEND", exported.alphaMode);
             }
             {
-                var material = Resources.Load<Material>("Materials/mtoon_opaque");
-                var exporter = new VRMMaterialExporter();
-                var exported = exporter.ExportMaterial(material, null);
-                Assert.NotNull(exported.extensions.KHR_materials_unlit);
+                var exported = ExportLoaded("Materials/mtoon_opaque");
+                Assert.True(UniGLTF.glTF_KHR_materials_unlit.IsEnable(exported));
                 Assert.AreEqual("OPAQUE", exported.alphaMode);
             }
             {
-                var material = Resources.Load<Material>("Materials/mtoon_transparent");
-                var exporter = new VRMMaterialExporter();
-                var exported = exporter.ExportMaterial(material, null);
-                Assert.NotNull(exported.extensions.KHR_materials_unlit);
+                var exported = ExportLoaded("Materials/mtoon_transparent");
+                Assert.True(UniGLTF.glTF_KHR_materials_unlit.IsEnable(exported));
                 Assert.AreEqual("BLEND", exported.alphaMode);
             }
             {
-                var material = Resources.Load<Material>("Materials/mtoon_cutout");
-                var exporter = new VRMMaterialExporter();
-                var exported = exporter.ExportMaterial(material, null);
-                Assert.NotNull(exported.extensions.KHR_materials_unlit);
+                var exported = ExportLoaded("Materials/mtoon_cutout");
+                Assert.True(UniGLTF.glTF_KHR_materials_unlit.IsEnable(exported));
                 Assert.AreEqual("MASK", exported.alphaMode);
             }
             {
-                var material = Resources.Load<Material>("Materials/mtoon_culloff");
-                var exporter = new VRMMaterialExporter();
-                var exported = exporter.ExportMaterial(material, null);
-                Assert.NotNull(exported.extensions.KHR_materials_unlit);
+                var exported = ExportLoaded("Materials/mtoon_culloff");
+                Assert.True(UniGLTF.glTF_KHR_materials_unlit.IsEnable(exported));
                 Assert.True(exported.doubleSided);
             }
         }
-    */
     }
 }