Add /api/transcribe endpoint with Whisper

tests/test_main.py

@@ -1,4 +1,6 @@
-"""Tests for the FastAPI application."""
+"""Tests for the FastAPI micro-api."""
+
+import io
 
 import pytest
 from fastapi.testclient import TestClient
@@ -26,30 +28,76 @@ class TestHealth:
         assert data["status"] == "running"
 
 
+class TestTranscribe:
+    def test_transcribe_no_file(self):
+        response = client.post("/api/transcribe")
+        assert response.status_code == 422  # FastAPI validation error
+
+    def test_transcribe_invalid_model(self):
+        # Create a tiny WAV file (44-byte header + silence)
+        wav_header = (
+            b"RIFF\x24\x00\x00\x00WAVEfmt \x10\x00\x00\x00"
+            b"\x01\x00\x01\x00\x44\xac\x00\x00\x88\x58\x01\x00"
+            b"\x02\x00\x10\x00data\x00\x00\x00\x00"
+        )
+        response = client.post(
+            "/api/transcribe?model=invalid_model",
+            files={"file": ("test.wav", io.BytesIO(wav_header), "audio/wav")},
+        )
+        assert response.status_code == 400
+        assert "Invalid model" in response.json()["detail"]
+
+    def test_transcribe_invalid_format(self):
+        response = client.post(
+            "/api/transcribe",
+            files={"file": ("test.txt", io.BytesIO(b"hello"), "text/plain")},
+        )
+        assert response.status_code == 400
+        assert "Unsupported format" in response.json()["detail"]
+
+    def test_transcribe_empty_file(self):
+        response = client.post(
+            "/api/transcribe",
+            files={"file": ("empty.wav", io.BytesIO(b""), "audio/wav")},
+        )
+        assert response.status_code == 400
+        assert "Empty" in response.json()["detail"]
+
+    def test_transcribe_accepts_wav_with_tiny_model(self):
+        """Test that the endpoint accepts a valid WAV file (tiny model won't load)."""
+        wav_header = (
+            b"RIFF\x24\x00\x00\x00WAVEfmt \x10\x00\x00\x00"
+            b"\x01\x00\x01\x00\x44\xac\x00\x00\x88\x58\x01\x00"
+            b"\x02\x00\x10\x00data\x00\x00\x00\x00"
+        )
+        response = client.post(
+            "/api/transcribe?model=tiny",
+            files={"file": ("test.wav", io.BytesIO(wav_header), "audio/wav")},
+        )
+        # 422 if file format is too broken for whisper, 200 if it just returns empty
+        # 500 if model not downloaded (expected in CI)
+        assert response.status_code in (200, 422, 500)
+
+
 class TestDatabase:
     def test_init_db_creates_tables(self):
         from app.database import init_db
-
-        # Should not raise
         init_db()
 
 
 class TestModels:
     def test_item_create_validation(self):
         from app.models import ItemCreate
-
         item = ItemCreate(name="test-item")
         assert item.name == "test-item"
 
     def test_item_create_requires_name(self):
         from app.models import ItemCreate
-
         with pytest.raises(Exception):
             ItemCreate()
 
     def test_item_response_serialization(self):
         from app.models import ItemResponse
-
         item = ItemResponse(id=1, name="test")
         data = item.model_dump()
         assert data["id"] == 1