feat: Customizable OpenAI prompts (#5146) (#6588)

Co-authored-by: Michael Genson <71845777+michael-genson@users.noreply.github.com>
Co-authored-by: Michael Genson <genson.michael@gmail.com>

tests/unit_tests/services_tests/test_openai_service.py

@@ -0,0 +1,77 @@
+import pytest
+
+import mealie.services.openai.openai as openai_module
+from mealie.services.openai.openai import OpenAIService
+
+
+class _SettingsStub:
+    OPENAI_ENABLED = True
+    OPENAI_MODEL = "gpt-4o"
+    OPENAI_WORKERS = 1
+    OPENAI_SEND_DATABASE_DATA = False
+    OPENAI_ENABLE_IMAGE_SERVICES = True
+    OPENAI_CUSTOM_PROMPT_DIR = None
+    OPENAI_BASE_URL = None
+    OPENAI_API_KEY = "dummy"
+    OPENAI_REQUEST_TIMEOUT = 30
+    OPENAI_CUSTOM_HEADERS = {}
+    OPENAI_CUSTOM_PARAMS = {}
+
+
+@pytest.fixture()
+def settings_stub(tmp_path, monkeypatch):
+    s = _SettingsStub()
+
+    prompts_dir = tmp_path / "prompts"
+    (prompts_dir / "recipes").mkdir(parents=True)
+    default_prompt = prompts_dir / "recipes" / "parse-recipe-ingredients.txt"
+    default_prompt.write_text("DEFAULT PROMPT")
+
+    monkeypatch.setattr(OpenAIService, "PROMPTS_DIR", prompts_dir)
+
+    def _fake_get_app_settings():
+        return s
+
+    monkeypatch.setattr(openai_module, "get_app_settings", _fake_get_app_settings)
+    return s
+
+
+def test_get_prompt_default_only(settings_stub):
+    svc = OpenAIService()
+    out = svc.get_prompt("recipes.parse-recipe-ingredients")
+    assert out == "DEFAULT PROMPT"
+
+
+def test_get_prompt_custom_dir_used(settings_stub, tmp_path):
+    custom_dir = tmp_path / "custom"
+    (custom_dir / "recipes").mkdir(parents=True)
+    (custom_dir / "recipes" / "parse-recipe-ingredients.txt").write_text("CUSTOM PROMPT")
+
+    settings_stub.OPENAI_CUSTOM_PROMPT_DIR = str(custom_dir)
+
+    svc = OpenAIService()
+    out = svc.get_prompt("recipes.parse-recipe-ingredients")
+    assert out == "CUSTOM PROMPT"
+
+
+def test_get_prompt_custom_empty_falls_back_to_default(settings_stub, tmp_path):
+    custom_dir = tmp_path / "custom"
+    (custom_dir / "recipes").mkdir(parents=True)
+    (custom_dir / "recipes" / "parse-recipe-ingredients.txt").write_text("")
+
+    settings_stub.OPENAI_CUSTOM_PROMPT_DIR = str(custom_dir)
+    svc = OpenAIService()
+    out = svc.get_prompt("recipes.parse-recipe-ingredients")
+    assert out == "DEFAULT PROMPT"
+
+
+def test_get_prompt_raises_when_no_files(settings_stub, monkeypatch):
+    # Point PROMPTS_DIR to an empty temp folder (already done in fixture) but remove default file
+    prompts_dir = OpenAIService.PROMPTS_DIR
+    for p in prompts_dir.rglob("*.txt"):
+        p.unlink()
+
+    svc = OpenAIService()
+    with pytest.raises(OSError) as ei:
+        svc.get_prompt("recipes.parse-recipe-ingredients")
+    assert "Unable to load prompt" in str(ei.value)