fix(frontend): Weekly view must always send an explicit date to /grade

frontend/tests/unit/test_app_js_grade_date.py

@@ -0,0 +1,57 @@
+"""Regression guard for the grade-URL "today" date bug: runGrade() in app.js used
+to omit `date` from the /api/v2/grade request whenever the selected date equaled
+the viewer's local today, so the backend fell back to ITS OWN UTC today
+(api_grade's `date` param default in backend/web/app.py) -- a day behind local
+midnight for any viewer east of UTC. Reported from Kaunas (UTC+3): asking for
+the Weekly tab on 7/26 rendered 7/25.
+
+There is no JS/DOM test harness in this repo to drive app.js and assert on the
+real fetch() URL it builds: static/package.json declares zero dependencies (no
+jest/playwright/node test runner), no such runner is wired into scripts/test.sh
+or any workflow, and server/**/*_test.go (the Go suite CI actually gates on)
+covers the Go SSR layer only, never static/*.js's runtime behavior. So this
+can't be a behavioral test. What it CAN do, hermetically, through the same
+served-asset route test_pages.py already exercises (`GET {B}/app.js`), is treat
+the real shipped source as data and assert the structural property the fix
+guarantees: runGrade() builds exactly one grade URL and always includes an
+explicit `date=`, rather than branching on whether the selected date is "today"
+and omitting it in that case.
+
+This fails against the pre-fix source and passes against the fixed source --
+a source guard, not a substitute for a real behavioral test.
+"""
+import re
+
+B = "/thermograph"  # matches THERMOGRAPH_BASE set in tests/conftest.py
+
+
+def _run_grade_body(client) -> str:
+    r = client.get(f"{B}/app.js")
+    assert r.status_code == 200
+    src = r.text
+    m = re.search(r"async function runGrade\(\) \{\n(.*?)\n\}\n", src, re.DOTALL)
+    assert m, "runGrade() not found in app.js -- update this test if it moved/was renamed"
+    return m.group(1)
+
+
+def test_run_grade_always_sends_explicit_date(client):
+    """The historical bug: `dateInput.value === todayISO() ? grade?q : grade?q&date=...`
+    omitted `date` for "today", so the backend's own UTC-today fallback rendered the
+    previous day for any UTC+ viewer between their local midnight and UTC midnight."""
+    body = _run_grade_body(client)
+    assert not re.search(r"dateInput\.value\s*===\s*todayISO\(\)", body), \
+        "runGrade() still branches on today to decide whether to send date="
+    assert body.count("grade?") == 1, \
+        "runGrade() should build exactly one grade URL, not two divergent branches"
+    assert re.search(r"date=\$\{[^}]+\}", body), \
+        "runGrade() must always build the URL with an explicit date= param"
+
+
+def test_run_grade_never_sends_an_empty_date(client):
+    """A cleared native date field reports dateInput.value === "" (day.js guards the
+    same input for the same reason). An empty date= hits the identical server-UTC
+    fallback this fix exists to avoid, so runGrade() must fall back to the viewer's
+    own local today rather than ever send the param empty."""
+    body = _run_grade_body(client)
+    assert re.search(r"dateInput\.value\s*\|\|\s*todayISO\(\)", body), \
+        "runGrade() should fall back to todayISO() when dateInput.value is empty"