Add tests for extract_barcode_from_image

9 new test cases covering: plain digit response, thinking-tag stripping,
digit extraction from surrounding text, empty/no-digit response → None,
exception handling → None, correct model/URL forwarding, EAN_PROMPT usage,
and base64 image encoding in request payload.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_vision_llm.py

@@ -1,8 +1,11 @@
 """Tests für die Vision-LLM JSON-Extraktion."""
 
+from pathlib import Path
+from unittest.mock import MagicMock, patch
+
 import pytest
 
-from musiksammlung.vision_llm import _extract_json
+from musiksammlung.vision_llm import EAN_PROMPT, _extract_json, extract_barcode_from_image
 
 
 def test_extract_pure_json():
@@ -35,3 +38,90 @@ def test_extract_json_empty_raises():
 def test_extract_json_no_json_raises():
     with pytest.raises(ValueError, match="Kein JSON"):
         _extract_json("Hier ist kein JSON, nur Text.")
+
+
+# ---------------------------------------------------------------------------
+# extract_barcode_from_image
+# ---------------------------------------------------------------------------
+
+def _mock_response(content: str) -> MagicMock:
+    """Erstellt einen Mock-httpx-Response mit gegebenem LLM-Inhalt."""
+    resp = MagicMock()
+    resp.json.return_value = {"message": {"content": content}}
+    resp.raise_for_status.return_value = None
+    return resp
+
+
+class TestExtractBarcodeFromImage:
+    """Tests für extract_barcode_from_image."""
+
+    def test_returns_digits_from_plain_response(self, tmp_path: Path) -> None:
+        img = tmp_path / "cover.jpg"
+        img.write_bytes(b"fake")
+        with patch("httpx.post", return_value=_mock_response("4006408262121")):
+            result = extract_barcode_from_image(img)
+        assert result == "4006408262121"
+
+    def test_strips_thinking_tags(self, tmp_path: Path) -> None:
+        img = tmp_path / "cover.jpg"
+        img.write_bytes(b"fake")
+        raw = "<think>Ich suche den Barcode...</think>\n4006408262121"
+        with patch("httpx.post", return_value=_mock_response(raw)):
+            result = extract_barcode_from_image(img)
+        assert result == "4006408262121"
+
+    def test_extracts_digits_from_surrounding_text(self, tmp_path: Path) -> None:
+        img = tmp_path / "cover.jpg"
+        img.write_bytes(b"fake")
+        raw = "Der EAN-Barcode lautet: 0028943753227."
+        with patch("httpx.post", return_value=_mock_response(raw)):
+            result = extract_barcode_from_image(img)
+        assert result == "0028943753227"
+
+    def test_returns_none_when_no_digits(self, tmp_path: Path) -> None:
+        img = tmp_path / "cover.jpg"
+        img.write_bytes(b"fake")
+        with patch("httpx.post", return_value=_mock_response("Kein Barcode erkannt.")):
+            result = extract_barcode_from_image(img)
+        assert result is None
+
+    def test_returns_none_on_empty_response(self, tmp_path: Path) -> None:
+        img = tmp_path / "cover.jpg"
+        img.write_bytes(b"fake")
+        with patch("httpx.post", return_value=_mock_response("")):
+            result = extract_barcode_from_image(img)
+        assert result is None
+
+    def test_returns_none_on_exception(self, tmp_path: Path) -> None:
+        img = tmp_path / "cover.jpg"
+        img.write_bytes(b"fake")
+        with patch("httpx.post", side_effect=Exception("connection refused")):
+            result = extract_barcode_from_image(img)
+        assert result is None
+
+    def test_sends_correct_model_and_url(self, tmp_path: Path) -> None:
+        img = tmp_path / "cover.jpg"
+        img.write_bytes(b"fake")
+        with patch("httpx.post", return_value=_mock_response("1234567890123")) as mock_post:
+            extract_barcode_from_image(img, model="my-model", base_url="http://myhost:11434")
+        url, = mock_post.call_args.args
+        assert url == "http://myhost:11434/api/chat"
+        assert mock_post.call_args.kwargs["json"]["model"] == "my-model"
+
+    def test_uses_ean_prompt(self, tmp_path: Path) -> None:
+        img = tmp_path / "cover.jpg"
+        img.write_bytes(b"fake")
+        with patch("httpx.post", return_value=_mock_response("9783161484100")) as mock_post:
+            extract_barcode_from_image(img)
+        messages = mock_post.call_args.kwargs["json"]["messages"]
+        assert messages[0]["content"] == EAN_PROMPT
+
+    def test_image_is_base64_encoded_in_request(self, tmp_path: Path) -> None:
+        img = tmp_path / "cover.jpg"
+        img.write_bytes(b"test image data")
+        with patch("httpx.post", return_value=_mock_response("0000000000000")) as mock_post:
+            extract_barcode_from_image(img)
+        messages = mock_post.call_args.kwargs["json"]["messages"]
+        import base64
+        expected_b64 = base64.b64encode(b"test image data").decode()
+        assert messages[0]["images"] == [expected_b64]