From 4f3fe64cad09606f3aeaccdcceb14f220d2785f5 Mon Sep 17 00:00:00 2001
From: Experiments DB Dev <dev@experiments-db.local>
Date: Sun, 19 Jul 2026 15:18:56 -0400
Subject: [PATCH] test(export): stale-group + same-date ordinal coverage;
 comment/guard polish

---
 frontend/src/components/ExportDataModal.jsx |  2 +-
 frontend/src/lib/dataExport.js              |  4 +++-
 frontend/tests/ExportDataModal.test.jsx     | 11 +++++++++++
 frontend/tests/dataExport.test.js           | 10 ++++++++++
 4 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/frontend/src/components/ExportDataModal.jsx b/frontend/src/components/ExportDataModal.jsx
index c97eedc..56c0eb2 100644
--- a/frontend/src/components/ExportDataModal.jsx
+++ b/frontend/src/components/ExportDataModal.jsx
@@ -44,7 +44,7 @@ export default function ExportDataModal({
     return () => { alive = false; };
   }, [experimentId]);
 
-  const params = useMemo(() => listExportableParams(dailyTemplate, statuses), [dailyTemplate, statuses]);
+  const params = useMemo(() => listExportableParams(dailyTemplate ?? [], statuses), [dailyTemplate, statuses]);
   const effDataId = dataId ?? params[0]?.id ?? null;
   const dataParam = params.find((p) => p.id === effDataId) ?? params[0] ?? null;
 
diff --git a/frontend/src/lib/dataExport.js b/frontend/src/lib/dataExport.js
index 27e5ed6..6ca80d3 100644
--- a/frontend/src/lib/dataExport.js
+++ b/frontend/src/lib/dataExport.js
@@ -207,7 +207,7 @@ function escapeCsvCell(value) {
 }
 
 // Serialize a matrix to an RFC-4180-ish CSV string (LF line endings):
-//   <pinned label>,<pinned value>
+//   Data,<metric>
 //   (blank line)
 //   [Group,<group per subject column>]    -- only when groupAxis === 'col'
 //   <corner>[,Group?],<column headers...>
@@ -222,6 +222,8 @@ export function toCSV(matrix) {
     lines.push(groupRow.map(escapeCsvCell).join(','));
   }
 
+  // toCSV is a general serializer; the subject-series builder never emits groupAxis
+  // === 'row' (only 'col' or null), but the branch is retained for that generality.
   const header = matrix.groupAxis === 'row'
     ? ['Group', matrix.corner, ...matrix.columns.map((c) => c.label)]
     : [matrix.corner, ...matrix.columns.map((c) => c.label)];
diff --git a/frontend/tests/ExportDataModal.test.jsx b/frontend/tests/ExportDataModal.test.jsx
index 2cdd755..de741fc 100644
--- a/frontend/tests/ExportDataModal.test.jsx
+++ b/frontend/tests/ExportDataModal.test.jsx
@@ -110,4 +110,15 @@ describe('ExportDataModal', () => {
     expect(text).toMatch(/^Group,Control,Drug$/m);
     await dl.restore();
   });
+
+  it('a stale/unset group field coerces to None (no Group row in the export)', async () => {
+    const dl = mockDownload();
+    renderModal({ groupField: 'ghost-field' });
+    await screen.findByLabelText('X axis (rows)');
+    await waitFor(() => expect(screen.getByText(/2 rows/i)).toBeInTheDocument());
+    fireEvent.click(screen.getByText('Export CSV'));
+    const text = await readBlobText(dl.getBlob());
+    expect(text).not.toMatch(/^Group,/m);
+    await dl.restore();
+  });
 });
diff --git a/frontend/tests/dataExport.test.js b/frontend/tests/dataExport.test.js
index 4ecd091..0ea0add 100644
--- a/frontend/tests/dataExport.test.js
+++ b/frontend/tests/dataExport.test.js
@@ -237,6 +237,16 @@ describe('buildSampleIndex', () => {
     expect(idx.get('a1').get(250).date).toContain('2026-07-01');
     expect(idx.get('a1').get(260).date).toContain('2026-07-03');
   });
+  it('# days reach counts per-status, not per-distinct-date (same-day statuses get separate ordinals)', () => {
+    const sameDay = [
+      { animal_id: 'z1', date: '2026-07-01T08:00:00Z', analysis_summary: { total: 1 } },
+      { animal_id: 'z1', date: '2026-07-01T20:00:00Z', analysis_summary: { total: 2 } },
+    ];
+    const idx = buildSampleIndex(sameDay, '__days__', []);
+    expect(idx.get('z1').has(1)).toBe(true);
+    expect(idx.get('z1').has(2)).toBe(true);
+    expect(idx.get('z1').has(3)).toBe(false);
+  });
 });
 
 import { buildSubjectSeriesMatrix } from '../src/lib/dataExport';