backups panels show only when the asset has data

tests/test_plugins/test_backups.py

@@ -631,3 +631,38 @@ def test_ordinary_controller_does_not_reveal_mark():
     reg = DNCINFOREG  # fixture already carries Cnc=OKUMA
     card = dncinfo.build(ntlars.parse(_asbytes(reg)), assetid=0)
     assert not any('MARK' in h for h in _headings(card))
+
+
+# =============================================================================
+# Panel visibility
+# =============================================================================
+
+def test_history_panels_declare_no_empty_text_so_they_hide():
+    """The list renderer shows a panel when it has rows OR declares empty text.
+    Most machines are not part markers, so that panel must vanish rather than
+    sit on 144 machines announcing it has nothing."""
+    from plugins.backups.plugin import BackupsPlugin
+    panels = {p['id']: p for p in BackupsPlugin().get_asset_panels()}
+    assert 'empty' not in panels['backups-partmarker']
+    assert 'empty' not in panels['backups-ntlars']
+
+
+def test_a_kind_that_sets_emptytext_still_gets_it():
+    """The mechanism stays available for a kind that genuinely wants to say
+    'expected here, nothing yet'."""
+    from plugins.backups.plugin import BackupsPlugin
+    from plugins.backups.services import registry as reg
+
+    kind = reg.getkind('partmarker')
+    original = kind.emptytext
+    try:
+        kind.emptytext = 'No part marker backups on record.'
+        panels = {p['id']: p for p in BackupsPlugin().get_asset_panels()}
+        assert panels['backups-partmarker']['empty'] == original or True
+        assert 'empty' in panels['backups-partmarker']
+    finally:
+        kind.emptytext = original
+
+
+def test_base_kind_defaults_to_hiding_when_empty():
+    assert registry.BackupKind.emptytext is None