Add tests and validation for EventTheme schema

Introduced extensive test cases to validate `EventTheme` schemas, ensuring proper handling of valid and invalid inputs, optional fields, and partial updates. Enhanced schema validation by adding constraints for `name`, `color_palette`, and `fonts` fields, as well as updating `id` to use `UUID` type for consistency. These changes improve data integrity and increase confidence in schema-related functionality.

backend/app/schemas/event_theme.py

@@ -1,13 +1,27 @@
+# app/schemas/event_theme.py
 from typing import Dict, Optional
-from pydantic import BaseModel
+from uuid import UUID  # Add this import
+from pydantic import BaseModel, Field, validator, field_validator
 
 
 class EventThemeBase(BaseModel):
-    name: str
+    name: str = Field(..., min_length=1)  # Ensures name is not empty
     description: Optional[str] = None
     preview_image_url: Optional[str] = None
-    color_palette: Dict[str, str]
-    fonts: Dict[str, str]
+    color_palette: Dict[str, str] = Field(..., min_items=1)  # Ensures at least one color
+    fonts: Dict[str, str] = Field(..., min_items=1)  # Ensures at least one font
+
+    @field_validator('color_palette')
+    def validate_color_palette(cls, v):
+        if not v:
+            raise ValueError("color_palette cannot be empty")
+        return v
+
+    @field_validator('fonts')
+    def validate_fonts(cls, v):
+        if not v:
+            raise ValueError("fonts cannot be empty")
+        return v
 
 
 class EventThemeCreate(EventThemeBase):
@@ -20,12 +34,18 @@ class EventThemeUpdate(EventThemeBase):
     fonts: Optional[Dict[str, str]] = None
 
 
+# Move EventThemeInDBBase before EventThemeResponse
 class EventThemeInDBBase(EventThemeBase):
-    id: str
+    id: UUID  # Changed from str to UUID to match the model
 
     class Config:
         from_attributes = True
 
 
+# Now EventThemeResponse can properly inherit from EventThemeInDBBase
+class EventThemeResponse(EventThemeInDBBase):
+    pass
+
+
 class EventTheme(EventThemeInDBBase):
     pass