tests: Add tests for deleting prompts by ID (#2156)

# Description

Please include a summary of the changes and the related issue. Please
also include relevant motivation and context.

## Checklist before requesting a review

Please delete options that are not relevant.

- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented hard-to-understand areas
- [ ] I have ideally added tests that prove my fix is effective or that
my feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged

## Screenshots (if appropriate):

backend/modules/prompt/tests/test_prompt.py

@@ -1,3 +1,11 @@
+import uuid
+
+import pytest
+from fastapi import HTTPException
+from modules.prompt.repository.prompts import Prompts
+from modules.prompt.service.prompt_service import DeletePromptResponse
+
+
 def test_get_public_prompts(client, api_key):
     response = client.get(
         "/prompts",
@@ -5,3 +13,30 @@ def test_get_public_prompts(client, api_key):
     )
     assert response.status_code == 200
     assert len(response.json()) == 0
+
+
+def test_delete_prompt_by_id():
+    # Arrange
+    prompts = Prompts()
+    prompt_id = uuid.uuid4()  # Generate a valid UUID
+
+    # Act
+    result = prompts.delete_prompt_by_id(prompt_id)
+
+    # Assert
+    assert isinstance(result, DeletePromptResponse)
+    assert result.status == "deleted"
+    assert result.prompt_id == prompt_id
+
+
+def test_delete_prompt_by_id_not_found():
+    # Arrange
+    prompts = Prompts()
+    prompt_id = uuid.uuid4()  # Generate a valid UUID
+
+    # Act and Assert
+    with pytest.raises(HTTPException) as exc_info:
+        prompts.delete_prompt_by_id(prompt_id)
+
+    assert exc_info.value.status_code == 404
+    assert str(exc_info.value.detail) == "Prompt not found"