no headlines in window{% if active_include or active_exclude %} (after tag filter){% endif %}
{% else %}
{% for h in headlines %}
{{ h.age }}
{{ h.source }}
{{ h.title }}
+
+ {% for t in h.tags or [] %}{{ tag_labels.get(t, t) }}{% endfor %}
+
{% if h.iso %}
{% else %}
diff --git a/tests/test_news_tagging.py b/tests/test_news_tagging.py
new file mode 100644
index 0000000..e4f9bff
--- /dev/null
+++ b/tests/test_news_tagging.py
@@ -0,0 +1,130 @@
+"""Tests for the deterministic half of news_tagging: vocabulary filtering
+and JSON-response parsing. The LLM call itself isn't exercised."""
+from __future__ import annotations
+
+import pytest
+
+from app.services.news_tagging import (
+ MAX_TAGS_PER_HEADLINE,
+ TAG_LABELS,
+ TAG_VOCABULARY,
+ _parse_batch_response,
+ _validate_tags,
+)
+
+
+# ---------------------------------------------------------------------------
+# Vocabulary integrity
+# ---------------------------------------------------------------------------
+
+
+def test_every_vocab_tag_has_a_label():
+ """Display labels must cover every tag — missing keys would render
+ the raw machine-name in the UI."""
+ for t in TAG_VOCABULARY:
+ assert t in TAG_LABELS, f"missing label for {t}"
+
+
+def test_other_is_the_fallback_tag():
+ assert "other" in TAG_VOCABULARY
+
+
+# ---------------------------------------------------------------------------
+# _validate_tags
+# ---------------------------------------------------------------------------
+
+
+def test_validate_drops_unknown_tags():
+ out = _validate_tags(["markets", "wibble", "tech"])
+ assert out == ["markets", "tech"]
+
+
+def test_validate_normalises_spaces_to_hyphens():
+ """Common drift: model returns 'monetary policy' instead of
+ 'monetary-policy'. We normalise."""
+ out = _validate_tags(["monetary policy"])
+ assert out == ["monetary-policy"]
+
+
+def test_validate_normalises_case():
+ out = _validate_tags(["MARKETS", "Geopolitics"])
+ assert out == ["markets", "geopolitics"]
+
+
+def test_validate_caps_at_max_tags():
+ out = _validate_tags(["markets", "tech", "china", "economy", "energy"])
+ assert len(out) == MAX_TAGS_PER_HEADLINE
+
+
+def test_validate_dedupes():
+ out = _validate_tags(["markets", "markets", "tech"])
+ assert out == ["markets", "tech"]
+
+
+def test_validate_rejects_non_list():
+ assert _validate_tags(None) == []
+ assert _validate_tags("markets") == []
+ assert _validate_tags({"tag": "markets"}) == []
+
+
+def test_validate_skips_non_string_entries():
+ out = _validate_tags(["markets", 42, None, "tech"])
+ assert out == ["markets", "tech"]
+
+
+# ---------------------------------------------------------------------------
+# _parse_batch_response
+# ---------------------------------------------------------------------------
+
+
+def test_parse_basic_json_array():
+ raw = '[{"id": 1, "tags": ["markets", "tech"]}, {"id": 2, "tags": ["china"]}]'
+ out = _parse_batch_response(raw, {1, 2})
+ assert out == {1: ["markets", "tech"], 2: ["china"]}
+
+
+def test_parse_strips_leading_prose():
+ """Models occasionally prepend 'Here is the output:' before the JSON."""
+ raw = 'Sure! Here are the tags:\n[{"id": 1, "tags": ["markets"]}]'
+ out = _parse_batch_response(raw, {1})
+ assert out == {1: ["markets"]}
+
+
+def test_parse_strips_markdown_fences():
+ raw = "```json\n[{\"id\": 1, \"tags\": [\"tech\"]}]\n```"
+ out = _parse_batch_response(raw, {1})
+ assert out == {1: ["tech"]}
+
+
+def test_parse_drops_unexpected_ids():
+ raw = '[{"id": 99, "tags": ["markets"]}, {"id": 1, "tags": ["tech"]}]'
+ out = _parse_batch_response(raw, {1, 2})
+ assert out == {1: ["tech"]}
+
+
+def test_parse_empty_tags_falls_back_to_other():
+ """An item whose tags list ends up empty after validation gets
+ tagged 'other' so the row is marked tagged, not left NULL."""
+ raw = '[{"id": 1, "tags": ["nonsense"]}]'
+ out = _parse_batch_response(raw, {1})
+ assert out == {1: ["other"]}
+
+
+def test_parse_unparseable_returns_empty():
+ """Garbage in → empty out. The caller leaves those rows untagged
+ so they get retried on the next run."""
+ assert _parse_batch_response("nope, no JSON here", {1}) == {}
+ assert _parse_batch_response("[invalid json", {1}) == {}
+
+
+def test_parse_ignores_non_dict_items():
+ raw = '[{"id": 1, "tags": ["markets"]}, "lol", null, {"id": 2, "tags": ["tech"]}]'
+ out = _parse_batch_response(raw, {1, 2})
+ assert out == {1: ["markets"], 2: ["tech"]}
+
+
+def test_parse_handles_string_id_coercion():
+ """Some models render the id as a string. We coerce."""
+ raw = '[{"id": "1", "tags": ["markets"]}]'
+ out = _parse_batch_response(raw, {1})
+ assert out == {1: ["markets"]}