diff --git a/tests/auth/test_jwt.py b/tests/auth/test_jwt.py
index 5eb81ec..0866ec9 100644
--- a/tests/auth/test_jwt.py
+++ b/tests/auth/test_jwt.py
@@ -52,6 +52,16 @@ class TestJWTAuth:
         with pytest.raises(ValueError, match="JWT token cannot be empty"):
             JWTAuth(None, mock_wiki_base_url)
 
+    def test_init_with_empty_base_url_raises_error(self, mock_jwt_token):
+        """Test that empty base URL raises ValueError."""
+        with pytest.raises(ValueError, match="Base URL cannot be empty"):
+            JWTAuth(mock_jwt_token, "")
+
+    def test_init_with_whitespace_base_url_raises_error(self, mock_jwt_token):
+        """Test that whitespace-only base URL raises ValueError."""
+        with pytest.raises(ValueError, match="Base URL cannot be empty"):
+            JWTAuth(mock_jwt_token, "   ")
+
     def test_get_headers_returns_bearer_token(self, jwt_auth, mock_jwt_token):
         """Test that get_headers returns proper Authorization header."""
         headers = jwt_auth.get_headers()
diff --git a/tests/endpoints/test_assets.py b/tests/endpoints/test_assets.py
index 0ec29dd..d1ba662 100644
--- a/tests/endpoints/test_assets.py
+++ b/tests/endpoints/test_assets.py
@@ -161,3 +161,347 @@ class TestAssetsEndpoint:
 
         with pytest.raises(ValidationError):
             endpoint.rename(1, "")
+
+    # Move operations
+    def test_move_asset(self, endpoint):
+        """Test moving an asset to a different folder."""
+        mock_response = {
+            "data": {
+                "assets": {
+                    "moveAsset": {
+                        "responseResult": {"succeeded": True},
+                        "asset": {
+                            "id": 1,
+                            "filename": "test.png",
+                            "ext": "png",
+                            "kind": "image",
+                            "mime": "image/png",
+                            "fileSize": 1024,
+                            "folderId": 5,
+                            "authorId": 1,
+                            "authorName": "Admin",
+                            "createdAt": "2024-01-01T00:00:00Z",
+                            "updatedAt": "2024-01-01T00:00:00Z",
+                        },
+                    }
+                }
+            }
+        }
+        endpoint._post = Mock(return_value=mock_response)
+
+        asset = endpoint.move(1, 5)
+
+        assert asset.folder_id == 5
+
+    def test_move_asset_validation_error(self, endpoint):
+        """Test move asset with invalid inputs."""
+        with pytest.raises(ValidationError):
+            endpoint.move(0, 1)  # Invalid asset ID
+
+        with pytest.raises(ValidationError):
+            endpoint.move(1, -1)  # Invalid folder ID
+
+    # Folder operations
+    def test_create_folder(self, endpoint):
+        """Test creating a folder."""
+        mock_response = {
+            "data": {
+                "assets": {
+                    "createFolder": {
+                        "responseResult": {"succeeded": True},
+                        "folder": {"id": 1, "slug": "documents", "name": "Documents"},
+                    }
+                }
+            }
+        }
+        endpoint._post = Mock(return_value=mock_response)
+
+        folder = endpoint.create_folder("documents", "Documents")
+
+        assert isinstance(folder, AssetFolder)
+        assert folder.slug == "documents"
+        assert folder.name == "Documents"
+
+    def test_create_folder_minimal(self, endpoint):
+        """Test creating a folder with minimal parameters."""
+        mock_response = {
+            "data": {
+                "assets": {
+                    "createFolder": {
+                        "responseResult": {"succeeded": True},
+                        "folder": {"id": 2, "slug": "images", "name": None},
+                    }
+                }
+            }
+        }
+        endpoint._post = Mock(return_value=mock_response)
+
+        folder = endpoint.create_folder("images")
+
+        assert folder.slug == "images"
+        assert folder.name is None
+
+    def test_create_folder_validation_error(self, endpoint):
+        """Test create folder with invalid slug."""
+        with pytest.raises(ValidationError):
+            endpoint.create_folder("")  # Empty slug
+
+        with pytest.raises(ValidationError):
+            endpoint.create_folder("///")  # Just slashes
+
+    def test_delete_folder(self, endpoint):
+        """Test deleting a folder."""
+        mock_response = {
+            "data": {
+                "assets": {
+                    "deleteFolder": {
+                        "responseResult": {"succeeded": True}
+                    }
+                }
+            }
+        }
+        endpoint._post = Mock(return_value=mock_response)
+
+        result = endpoint.delete_folder(1)
+
+        assert result is True
+
+    def test_delete_folder_validation_error(self, endpoint):
+        """Test delete folder with invalid ID."""
+        with pytest.raises(ValidationError):
+            endpoint.delete_folder(0)
+
+        with pytest.raises(ValidationError):
+            endpoint.delete_folder(-1)
+
+    # List operations with filters
+    def test_list_assets_with_folder_filter(self, endpoint):
+        """Test listing assets filtered by folder."""
+        mock_response = {
+            "data": {
+                "assets": {
+                    "list": [
+                        {
+                            "id": 1,
+                            "filename": "doc.pdf",
+                            "ext": "pdf",
+                            "kind": "binary",
+                            "mime": "application/pdf",
+                            "fileSize": 2048,
+                            "folderId": 1,
+                            "folder": {"id": 1, "slug": "documents", "name": "Documents"},
+                            "authorId": 1,
+                            "authorName": "Admin",
+                            "createdAt": "2024-01-01T00:00:00Z",
+                            "updatedAt": "2024-01-01T00:00:00Z",
+                        }
+                    ]
+                }
+            }
+        }
+        endpoint._post = Mock(return_value=mock_response)
+
+        assets = endpoint.list(folder_id=1)
+
+        assert len(assets) == 1
+        assert assets[0].folder_id == 1
+
+    def test_list_assets_with_kind_filter(self, endpoint):
+        """Test listing assets filtered by kind."""
+        mock_response = {
+            "data": {
+                "assets": {
+                    "list": [
+                        {
+                            "id": 1,
+                            "filename": "photo.jpg",
+                            "ext": "jpg",
+                            "kind": "image",
+                            "mime": "image/jpeg",
+                            "fileSize": 5120,
+                            "folderId": 0,
+                            "authorId": 1,
+                            "authorName": "Admin",
+                            "createdAt": "2024-01-01T00:00:00Z",
+                            "updatedAt": "2024-01-01T00:00:00Z",
+                        }
+                    ]
+                }
+            }
+        }
+        endpoint._post = Mock(return_value=mock_response)
+
+        assets = endpoint.list(kind="image")
+
+        assert len(assets) == 1
+        assert assets[0].kind == "image"
+
+    def test_list_assets_empty(self, endpoint):
+        """Test listing assets when none exist."""
+        mock_response = {"data": {"assets": {"list": []}}}
+        endpoint._post = Mock(return_value=mock_response)
+
+        assets = endpoint.list()
+
+        assert len(assets) == 0
+
+    # Error handling
+    def test_get_asset_not_found(self, endpoint):
+        """Test getting non-existent asset."""
+        mock_response = {
+            "data": {"assets": {"single": None}},
+            "errors": [{"message": "Asset not found"}],
+        }
+        endpoint._post = Mock(return_value=mock_response)
+
+        with pytest.raises(APIError, match="Asset not found"):
+            endpoint.get(999)
+
+    def test_delete_asset_failure(self, endpoint):
+        """Test delete asset API failure."""
+        mock_response = {
+            "data": {
+                "assets": {
+                    "deleteAsset": {
+                        "responseResult": {"succeeded": False, "message": "Permission denied"}
+                    }
+                }
+            }
+        }
+        endpoint._post = Mock(return_value=mock_response)
+
+        with pytest.raises(APIError, match="Permission denied"):
+            endpoint.delete(1)
+
+    def test_rename_asset_failure(self, endpoint):
+        """Test rename asset API failure."""
+        mock_response = {
+            "data": {
+                "assets": {
+                    "renameAsset": {
+                        "responseResult": {"succeeded": False, "message": "Name already exists"}
+                    }
+                }
+            }
+        }
+        endpoint._post = Mock(return_value=mock_response)
+
+        with pytest.raises(APIError, match="Name already exists"):
+            endpoint.rename(1, "duplicate.png")
+
+    def test_move_asset_failure(self, endpoint):
+        """Test move asset API failure."""
+        mock_response = {
+            "data": {
+                "assets": {
+                    "moveAsset": {
+                        "responseResult": {"succeeded": False, "message": "Folder not found"}
+                    }
+                }
+            }
+        }
+        endpoint._post = Mock(return_value=mock_response)
+
+        with pytest.raises(APIError, match="Folder not found"):
+            endpoint.move(1, 999)
+
+    def test_create_folder_failure(self, endpoint):
+        """Test create folder API failure."""
+        mock_response = {
+            "data": {
+                "assets": {
+                    "createFolder": {
+                        "responseResult": {"succeeded": False, "message": "Folder already exists"}
+                    }
+                }
+            }
+        }
+        endpoint._post = Mock(return_value=mock_response)
+
+        with pytest.raises(APIError, match="Folder already exists"):
+            endpoint.create_folder("existing")
+
+    def test_delete_folder_failure(self, endpoint):
+        """Test delete folder API failure."""
+        mock_response = {
+            "data": {
+                "assets": {
+                    "deleteFolder": {
+                        "responseResult": {"succeeded": False, "message": "Folder not empty"}
+                    }
+                }
+            }
+        }
+        endpoint._post = Mock(return_value=mock_response)
+
+        with pytest.raises(APIError, match="Folder not empty"):
+            endpoint.delete_folder(1)
+
+    # Pagination
+    def test_iter_all_assets(self, endpoint):
+        """Test iterating over all assets with pagination."""
+        # First page (smaller batch to ensure pagination works)
+        mock_response_page1 = {
+            "data": {
+                "assets": {
+                    "list": [
+                        {
+                            "id": i,
+                            "filename": f"file{i}.png",
+                            "ext": "png",
+                            "kind": "image",
+                            "mime": "image/png",
+                            "fileSize": 1024,
+                            "folderId": 0,
+                            "authorId": 1,
+                            "authorName": "Admin",
+                            "createdAt": "2024-01-01T00:00:00Z",
+                            "updatedAt": "2024-01-01T00:00:00Z",
+                        }
+                        for i in range(1, 6)  # 5 items
+                    ]
+                }
+            }
+        }
+
+        # Second page (empty - pagination stops)
+        mock_response_page2 = {"data": {"assets": {"list": []}}}
+
+        endpoint._post = Mock(
+            side_effect=[mock_response_page1, mock_response_page2]
+        )
+
+        all_assets = list(endpoint.iter_all(batch_size=5))
+
+        assert len(all_assets) == 5
+        assert all_assets[0].id == 1
+        assert all_assets[4].id == 5
+
+    # Normalization edge cases
+    def test_normalize_asset_data_minimal(self, endpoint):
+        """Test normalizing asset data with minimal fields."""
+        data = {
+            "id": 1,
+            "filename": "test.png",
+            "ext": "png",
+            "kind": "image",
+            "mime": "image/png",
+            "fileSize": 1024,
+        }
+
+        normalized = endpoint._normalize_asset_data(data)
+
+        assert normalized["id"] == 1
+        assert normalized["filename"] == "test.png"
+        # Check that snake_case fields are present
+        assert "file_size" in normalized
+        assert normalized["file_size"] == 1024
+
+    def test_list_folders_empty(self, endpoint):
+        """Test listing folders when none exist."""
+        mock_response = {"data": {"assets": {"folders": []}}}
+        endpoint._post = Mock(return_value=mock_response)
+
+        folders = endpoint.list_folders()
+
+        assert len(folders) == 0
diff --git a/wikijs/models/asset.py b/wikijs/models/asset.py
index ac32bc2..8cc5998 100644
--- a/wikijs/models/asset.py
+++ b/wikijs/models/asset.py
@@ -2,7 +2,7 @@
 
 from typing import Optional
 
-from pydantic import Field, field_validator
+from pydantic import ConfigDict, Field, field_validator
 
 from .base import BaseModel, TimestampedModel
 
@@ -10,15 +10,12 @@ from .base import BaseModel, TimestampedModel
 class AssetFolder(BaseModel):
     """Asset folder model."""
 
+    model_config = ConfigDict(populate_by_name=True)
+
     id: int = Field(..., description="Folder ID")
     slug: str = Field(..., description="Folder slug/path")
     name: Optional[str] = Field(None, description="Folder name")
 
-    class Config:
-        """Pydantic configuration."""
-
-        populate_by_name = True
-
 
 class Asset(TimestampedModel):
     """Wiki.js asset model.
@@ -75,10 +72,7 @@ class Asset(TimestampedModel):
         """Get file size in kilobytes."""
         return self.file_size / 1024
 
-    class Config:
-        """Pydantic configuration."""
-
-        populate_by_name = True
+    model_config = ConfigDict(populate_by_name=True)
 
 
 class AssetUpload(BaseModel):
@@ -102,10 +96,7 @@ class AssetUpload(BaseModel):
             raise ValueError("File path cannot be empty")
         return v.strip()
 
-    class Config:
-        """Pydantic configuration."""
-
-        populate_by_name = True
+    model_config = ConfigDict(populate_by_name=True)
 
 
 class AssetRename(BaseModel):
@@ -137,10 +128,7 @@ class AssetRename(BaseModel):
             raise ValueError("Filename cannot be empty")
         return v.strip()
 
-    class Config:
-        """Pydantic configuration."""
-
-        populate_by_name = True
+    model_config = ConfigDict(populate_by_name=True)
 
 
 class AssetMove(BaseModel):
@@ -170,10 +158,7 @@ class AssetMove(BaseModel):
             raise ValueError("Folder ID must be non-negative")
         return v
 
-    class Config:
-        """Pydantic configuration."""
-
-        populate_by_name = True
+    model_config = ConfigDict(populate_by_name=True)
 
 
 class FolderCreate(BaseModel):
@@ -199,7 +184,4 @@ class FolderCreate(BaseModel):
             raise ValueError("Slug cannot be just slashes")
         return v
 
-    class Config:
-        """Pydantic configuration."""
-
-        populate_by_name = True
+    model_config = ConfigDict(populate_by_name=True)
diff --git a/wikijs/models/group.py b/wikijs/models/group.py
index 64b246f..56e5fa8 100644
--- a/wikijs/models/group.py
+++ b/wikijs/models/group.py
@@ -2,7 +2,7 @@
 
 from typing import List, Optional
 
-from pydantic import Field, field_validator
+from pydantic import ConfigDict, Field, field_validator
 
 from .base import BaseModel, TimestampedModel
 
@@ -10,18 +10,17 @@ from .base import BaseModel, TimestampedModel
 class GroupPermission(BaseModel):
     """Group permission model."""
 
+    model_config = ConfigDict(populate_by_name=True)
+
     id: str = Field(..., description="Permission identifier")
     name: Optional[str] = Field(None, description="Permission name")
 
-    class Config:
-        """Pydantic configuration."""
-
-        populate_by_name = True
-
 
 class GroupPageRule(BaseModel):
     """Group page access rule model."""
 
+    model_config = ConfigDict(populate_by_name=True)
+
     id: str = Field(..., description="Rule identifier")
     path: str = Field(..., description="Page path pattern")
     roles: List[str] = Field(default_factory=list, description="Allowed roles")
@@ -29,24 +28,16 @@ class GroupPageRule(BaseModel):
     deny: bool = Field(default=False, description="Whether this is a deny rule")
     locales: List[str] = Field(default_factory=list, description="Allowed locales")
 
-    class Config:
-        """Pydantic configuration."""
-
-        populate_by_name = True
-
 
 class GroupUser(BaseModel):
     """User member of a group (minimal representation)."""
 
+    model_config = ConfigDict(populate_by_name=True)
+
     id: int = Field(..., description="User ID")
     name: str = Field(..., description="User name")
     email: str = Field(..., description="User email")
 
-    class Config:
-        """Pydantic configuration."""
-
-        populate_by_name = True
-
 
 class Group(TimestampedModel):
     """Wiki.js group model.
@@ -95,10 +86,7 @@ class Group(TimestampedModel):
             raise ValueError("Group name cannot exceed 255 characters")
         return v.strip()
 
-    class Config:
-        """Pydantic configuration."""
-
-        populate_by_name = True
+    model_config = ConfigDict(populate_by_name=True)
 
 
 class GroupCreate(BaseModel):
@@ -111,6 +99,8 @@ class GroupCreate(BaseModel):
         page_rules: List of page access rule configurations
     """
 
+    model_config = ConfigDict(populate_by_name=True)
+
     name: str = Field(..., min_length=1, max_length=255, description="Group name")
     redirect_on_login: Optional[str] = Field(
         None, alias="redirectOnLogin", description="Redirect path on login"
@@ -134,11 +124,6 @@ class GroupCreate(BaseModel):
             raise ValueError("Group name cannot exceed 255 characters")
         return v.strip()
 
-    class Config:
-        """Pydantic configuration."""
-
-        populate_by_name = True
-
 
 class GroupUpdate(BaseModel):
     """Model for updating an existing group.
@@ -152,6 +137,8 @@ class GroupUpdate(BaseModel):
         page_rules: Updated page access rules
     """
 
+    model_config = ConfigDict(populate_by_name=True)
+
     name: Optional[str] = Field(
         None, min_length=1, max_length=255, description="Group name"
     )
@@ -177,11 +164,6 @@ class GroupUpdate(BaseModel):
             raise ValueError("Group name cannot exceed 255 characters")
         return v.strip()
 
-    class Config:
-        """Pydantic configuration."""
-
-        populate_by_name = True
-
 
 class GroupAssignUser(BaseModel):
     """Model for assigning a user to a group.
@@ -191,14 +173,11 @@ class GroupAssignUser(BaseModel):
         user_id: User ID
     """
 
+    model_config = ConfigDict(populate_by_name=True)
+
     group_id: int = Field(..., alias="groupId", description="Group ID")
     user_id: int = Field(..., alias="userId", description="User ID")
 
-    class Config:
-        """Pydantic configuration."""
-
-        populate_by_name = True
-
 
 class GroupUnassignUser(BaseModel):
     """Model for removing a user from a group.
@@ -208,10 +187,7 @@ class GroupUnassignUser(BaseModel):
         user_id: User ID
     """
 
+    model_config = ConfigDict(populate_by_name=True)
+
     group_id: int = Field(..., alias="groupId", description="Group ID")
     user_id: int = Field(..., alias="userId", description="User ID")
-
-    class Config:
-        """Pydantic configuration."""
-
-        populate_by_name = True
diff --git a/wikijs/models/user.py b/wikijs/models/user.py
index bb71337..96ee627 100644
--- a/wikijs/models/user.py
+++ b/wikijs/models/user.py
@@ -3,7 +3,7 @@
 import re
 from typing import List, Optional
 
-from pydantic import EmailStr, Field, field_validator
+from pydantic import ConfigDict, EmailStr, Field, field_validator
 
 from .base import BaseModel, TimestampedModel
 
@@ -63,11 +63,7 @@ class User(TimestampedModel):
 
         return v.strip()
 
-    class Config:
-        """Pydantic model configuration."""
-
-        populate_by_name = True
-        str_strip_whitespace = True
+    model_config = ConfigDict(populate_by_name=True, str_strip_whitespace=True)
 
 
 class UserCreate(BaseModel):
@@ -122,11 +118,7 @@ class UserCreate(BaseModel):
 
         return v
 
-    class Config:
-        """Pydantic model configuration."""
-
-        populate_by_name = True
-        str_strip_whitespace = True
+    model_config = ConfigDict(populate_by_name=True, str_strip_whitespace=True)
 
 
 class UserUpdate(BaseModel):
@@ -185,8 +177,4 @@ class UserUpdate(BaseModel):
 
         return v
 
-    class Config:
-        """Pydantic model configuration."""
-
-        populate_by_name = True
-        str_strip_whitespace = True
+    model_config = ConfigDict(populate_by_name=True, str_strip_whitespace=True)