feat: locks/replace/compare/permalinks; perf: virtualization, LQIP, caching, diagnostics; add tests, docs, and issue/PR templates (flags OFF)

code/tests/test_compare_diffs.py

@@ -0,0 +1,52 @@
+import os
+import tempfile
+from pathlib import Path
+import importlib
+from starlette.testclient import TestClient
+
+
+def _write_csv(p: Path, rows):
+    p.write_text('\n'.join(rows), encoding='utf-8')
+
+
+def test_compare_diffs_with_temp_exports(monkeypatch):
+    with tempfile.TemporaryDirectory() as tmpd:
+        tmp = Path(tmpd)
+        # Create two CSV exports with small differences
+        a = tmp / 'A.csv'
+        b = tmp / 'B.csv'
+        header = 'Name,Count,Type,ManaValue\n'
+        _write_csv(a, [
+            header.rstrip('\n'),
+            'Card One,1,Creature,2',
+            'Card Two,2,Instant,1',
+            'Card Three,1,Sorcery,3',
+        ])
+        _write_csv(b, [
+            header.rstrip('\n'),
+            'Card Two,1,Instant,1',  # decreased in B
+            'Card Four,1,Creature,2',  # only in B
+            'Card Three,1,Sorcery,3',
+        ])
+        # Touch mtime so B is newer
+        os.utime(a, None)
+        os.utime(b, None)
+
+        # Point DECK_EXPORTS at this temp dir
+        monkeypatch.setenv('DECK_EXPORTS', str(tmp))
+        app_module = importlib.import_module('code.web.app')
+        client = TestClient(app_module.app)
+
+        # Compare A vs B
+        r = client.get(f'/decks/compare?A={a.name}&B={b.name}')
+        assert r.status_code == 200
+        body = r.text
+        # Only in A: Card One
+        assert 'Only in A' in body
+        assert 'Card One' in body
+        # Only in B: Card Four
+        assert 'Only in B' in body
+        assert 'Card Four' in body
+        # Changed list includes Card Two with delta -1
+        assert 'Card Two' in body
+        assert 'Decreased' in body or '( -1' in body or '(-1)' in body